VSM Versum Materials Inc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE

SECURITIES EXCHANGE ACT OF 1934

Filed by the Registrant  ☒                             Filed by a party other than the Registrant  ☐

Check the appropriate box:

VERSUM MATERIALS, INC.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

Dear Stockholder:

On April 12, 2019, Versum Materials, Inc., which is referred to as Versum, entered into a definitive Agreement and Plan of Merger, as it may be amended from time to time, which is referred to as the merger agreement, with Merck KGaA, Darmstadt, Germany, a German corporation with general partners, which is referred to as Parent, and EMD Performance Materials Holding, Inc., a Delaware corporation and a wholly-owned subsidiary of Parent, which is referred to as Merger Sub. Pursuant to the terms of the merger agreement, Merger Sub will merge with and into Versum, with Versum surviving and continuing as the surviving corporation in the merger and a wholly-owned subsidiary of Parent, which transaction is referred to as the merger.

Upon successful completion of the merger, our stockholders will have the right to receive $53.00 per share in cash, without interest and less any applicable withholding tax, for each share of common stock, par value $1.00 per share, of Versum, which is referred to as Versum common stock, that they own immediately prior to the effective time of the merger (other than shares (i) owned by Versum, Parent, Merger Sub or any other direct or indirect wholly-owned subsidiary of Parent, and in each case excluding any such shares owned by a benefit plan of Versum or held on behalf of third parties, and (ii) shares owned by stockholders who have not voted in favor of the merger and have demanded, perfected and not withdrawn or lost the right to demand, appraisal rights pursuant to Section 262 of the General Corporation Law of the State of Delaware).

Versum will hold a special meeting of stockholders of Versum in connection with the proposed merger, which is referred to as the special meeting.

At the special meeting, Versum stockholders will be asked to consider and vote on (1) the proposal to adopt the merger agreement, which is referred to as the merger agreement proposal, (2) the proposal to approve, on a non-binding advisory basis, specific compensatory arrangements between Versum and its named executive officers relating to the merger and (3) the proposal to adjourn the special meeting to solicit additional proxies if there are not sufficient votes to approve the merger agreement proposal or to ensure that any supplement or amendment to the accompanying proxy statement is timely provided to Versum stockholders. The board of directors of Versum unanimously recommends that Versum stockholders vote “FOR” each of the proposals to be considered at the special meeting.

We cannot complete the merger unless Versum stockholders approve the merger agreement proposal. Your vote on these matters is very important, regardless of the number of shares you own. Whether or not you plan to attend the special meeting in person, please promptly mark, sign and date the accompanying proxy and return it in the enclosed postage-paid envelope or authorize the individuals named on your proxy card to vote your shares by calling the toll-free telephone number or by using the Internet as described in the instructions included with your proxy card.

The accompanying proxy statement provides you with important information about the special meeting, the merger, and each of the proposals. We encourage you to read the entire document carefully.

We look forward to the successful completion of the merger.

Sincerely,

Guillermo Novo

President and Chief Executive Officer

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of the merger or determined if the accompanying proxy statement is accurate or complete. Any representation to the contrary is a criminal offense.

The accompanying proxy statement is dated May 13, 2019 and, together with the enclosed form of proxy, is first being mailed to Versum stockholders on or about May 14, 2019.

Versum Materials, Inc.

8555 South River Parkway

Tempe, Arizona 85284

(602) 282-1000

Whether or not you plan to attend the special meeting in person, Versum urges you to please promptly mark, sign and date the accompanying proxy and return it in the enclosed postage-paid envelope, call the toll-free telephone number or use the Internet as described in the instructions included with the proxy card, so that your shares may be represented and voted at the special meeting. If you hold your shares through a broker, bank or other nominee in “street name” (instead of as a registered holder) and you wish to vote in person at the special meeting, you must obtain a legal proxy from your bank, broker or other nominee and bring the legal proxy to the meeting in order to vote in person at the special meeting. You will need to bring identification along with either your notice of special meeting or proof of stock ownership to enter the special meeting. The use of video, still photography or audio recording at the special meeting is not permitted. For the safety of attendees, all bags, packages and briefcases are subject to inspection.

If you have any questions about the merger, please contact Versum at (602) 282-1000 or write to Versum Materials, Inc., Attn: Corporate Secretary, 8555 South River Parkway, Tempe, Arizona 85284.

If you have any questions about how to vote or direct a vote in respect of your shares of Versum common stock, you may contact Versum’s proxy solicitor, Innisfree M&A Incorporated, toll-free at (877) 456-3463 or call collect at (212) 750-5833.

Tempe, Arizona

Dated: May 13, 2019

TABLE OF CONTENTS

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QUESTIONS AND ANSWERS

The following are some questions that you, as a stockholder of Versum, may have regarding the merger and the other matters being considered at the special meeting of Versum’s stockholders, and brief answers to those questions. You are urged to carefully read this proxy statement and the other documents referred to in this proxy statement in their entirety because this section may not provide all the information that is important to you regarding these matters. Additional important information is contained in the annexes to, and the documents incorporated by reference into, this proxy statement. You may obtain the information incorporated by reference in this proxy statement, without charge, by following the instructions under the section entitled “ Where You Can Find More Information ” beginning on page 122.

In order to complete the merger, among other things, Versum stockholders must adopt the merger agreement in accordance with the DGCL.

Versum is holding the special meeting to obtain approval of the merger agreement proposal. Versum stockholders will also be asked to approve, on an advisory (non-binding) basis, the merger-related executive officer compensation payments that will or may be paid by Versum to its named executive officers in connection with the merger, and to approve the proposal to adjourn the special meeting to solicit additional proxies if there are not sufficient votes at the time of the special meeting to adopt the merger agreement or to ensure that any supplement or amendment to this proxy statement is timely provided to Versum stockholders.

Your vote is very important, regardless of the number of shares that you own. The adoption of the merger agreement is a condition to the obligations of Versum and Parent to complete the merger. Neither of the approvals of the compensation proposal or the adjournment proposal are conditions to the obligations of Versum or Parent to complete the merger.

If you choose to vote your shares in person at the special meeting, please bring required documentation in accordance with the section entitled “ The Special Meeting—Attending the Special Meeting ” beginning on page 32. The use of video, still photography or audio recording at the special meeting is not permitted. For the safety of attendees, all bags, packages and briefcases are subject to inspection.

Even if you plan to attend the special meeting, Versum recommends that you vote your shares in advance as described below so that your vote will be counted if you later decide not to attend or become unable to attend the special meeting. Shares held in “street name” may be voted in person by you only if you obtain a signed legal proxy from your bank, broker or other nominee giving you the right to vote the shares.

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If you do not return or submit your proxy or vote at the special meeting as provided in this proxy statement, the effect will be the same as a vote “ AGAINST ” the merger agreement proposal, and will have no effect on the compensation proposal or the adjournment proposal. The Versum board of directors unanimously recommends that you vote “ FOR ” the merger agreement proposal, “ FOR ” the compensation proposal and “ FOR ” the adjournment proposal.

We entered into the Parent merger agreement following a determination by the Versum board of directors that the proposal submitted by Parent on April 6, 2019 to acquire Versum for $53.00 per share in cash, without interest and less any applicable withholding taxes, represented a “Superior Proposal” as defined in the Entegris merger agreement.

For more information regarding the background of the merger, see the section entitled “ The Merger—Background of the Merger ” beginning on page 34.

Your votes are very important. You are encouraged to read this proxy statement carefully and return or submit your proxy promptly or vote at the special meeting in accordance with this proxy statement.

For more information regarding the merger consideration to be received by Versum stockholders if the merger is completed, see the section entitled “ The Merger Agreement—Merger Consideration ” beginning on page 82.

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At the effective time, each outstanding RSU award and each outstanding PSU award will be canceled in exchange for the right of the RSU award holder or PSU award holder, as applicable, to receive a deferred cash payment equal to the product of (i) the number of shares of Versum common stock underlying such RSU award or PSU award and (ii) the merger consideration. For PSU awards, the number of shares in the immediately preceding sentence will be determined based on actual performance through a shortened performance period ending immediately prior to the effective time, as determined in the good faith discretion of the compensation committee of the Versum board of directors. The deferred cash payments will (i) vest and settle on terms (including acceleration events) at least as favorable as were applicable to the corresponding RSU award or PSU award, as applicable, immediately prior to the effective time, except that deferred cash payments relating to PSU awards will no longer be subject to performance-based vesting criteria and (ii) other than RSU awards that were converted from equity-based awards granted by Air Products in connection with the spinoff, accrue interest at a rate equal to LIBOR plus 2.0% per annum, computed in accordance with the terms of the applicable award agreement evidencing such RSU award or PSU award, as applicable. Each deferred cash payment will vest in full on the original vesting date or, if the holder experiences a “covered termination” following the effective time and prior to the original vesting date, on the date of such “covered termination,” with the deferred cash payment settled in cash as soon as practicable, but in no event later than 10 business days, following such “covered termination,” or such later time as required to comply with Section 409A of the Code. For employees of Versum and its subsidiaries, a “covered termination” means a termination by Versum or one of its subsidiaries or their successor in interest without “cause” or, to the extent good reason rights are provided for in the award agreement (or employment or similar agreement) applicable to the corresponding RSU award or PSU award, a resignation by the employee for “good reason” (as such terms are defined in the applicable agreement), in either case, during the 24-month period following the effective time. For non-employee directors of Versum, a “covered termination” means the termination of their service as a director for any reason at or following the effective time.

At the effective time, each DSU award under the Director DCP will be fully vested and be converted into the right to receive a cash amount equal to (i) the number of shares of Versum common stock covered by the DSU award and (ii) the merger consideration, with such cash payment made to the holder no later than 30 business days following the effective time.

In considering the recommendations of the Versum board of directors, Versum stockholders should be aware that Versum directors and executive officers have interests in the merger that are different from, or in addition to, their interests as Versum stockholders. These interests may include, among others, the payment of severance benefits and acceleration of outstanding equity awards upon certain terminations of employment or service, the payment of retention bonuses and the combined company’s agreement to indemnify Versum directors and officers against certain claims and liabilities. For a more complete description of these interests, see the information provided in the section entitled “ The Merger—Interests of Versum’s Directors and Executive Officers in the Merger ” beginning on page 64.

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A “broker non-vote” occurs on an item when (a) a bank, broker or other nominee has discretionary authority to vote on one or more proposals to be voted on at a meeting of stockholders, but is not permitted to vote on other proposals without instructions from the beneficial owner of the shares and (b) the beneficial owner fails to provide the bank, broker or other nominee with such instructions.

Proposal 2: compensation proposal . Assuming a quorum is present, approval of the compensation proposal requires the affirmative vote of a majority of the votes cast at the special meeting on this proposal. Accordingly, a Versum stockholder’s abstention from voting, a broker non-vote or the failure of a Versum stockholder to vote (including the failure of a Versum stockholder who holds shares in “street name” through a bank, broker or other nominee to give voting instructions to that bank, broker or other nominee) will have NO EFFECT on the compensation proposal.

Proposal 3: adjournment proposal . The special meeting may be adjourned to solicit additional proxies if there are not sufficient votes at the time of the special meeting to approve the merger agreement proposal or to ensure that any supplement or amendment to this proxy statement is timely provided to Versum stockholders. Whether or not a quorum is present, the affirmative vote of a majority of the votes entitled to be cast who are present in person or represented by proxy at the special meeting is required to adjourn the special meeting. Accordingly, a Versum stockholder’s abstention from voting will have the same effect as a vote “ AGAINST ” the adjournment proposal, while a broker non-vote or the failure of a Versum stockholder to vote (including the failure of a Versum stockholder who holds shares in “street name” through a bank, broker or other nominee to give voting instructions to that bank, broker or other nominee) will have NO EFFECT on the adjournment proposal. The chairman of the special meeting may also adjourn the special meeting, whether or not there is a quorum.

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Shares in “street name.” Shares held in “street name” may be voted in person by you only if you obtain a signed legal proxy from your bank, broker or other nominee giving you the right to vote the shares. If you choose to vote your shares in person at the special meeting, please bring required documentation in accordance with the section entitled “ The Special Meeting—Attending the Special Meeting ” beginning on page 32.

Even if you plan to attend the special meeting, Versum recommends that you vote your shares in advance as described below so that your vote will be counted if you later decide not to attend or become unable to attend the special meeting. The use of video, still photography or audio recording is not permitted at the special meeting. For the safety of attendees, all bags, packages and briefcases are subject to inspection. Your compliance is appreciated.

Additional information on attending the special meeting can be found under the section entitled “ The Special Meeting ” beginning on page 28.

Additional information on voting procedures can be found under the section entitled “ The Special Meeting ” beginning on page 28.

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If your shares of Versum common stock are held by a bank, broker or other nominee, you are considered the beneficial owner of shares held in “street name,” and your bank, broker or other nominee is considered the stockholder of record with respect to those shares. Your bank, broker or other nominee will send you, as the beneficial owner, a package describing the procedure for voting your shares. You should follow the instructions provided by them to vote your shares. You are invited to attend the special meeting; however, you may not vote these shares in person at the special meeting unless you obtain a signed legal proxy, executed in your favor, from your bank, broker or other nominee that holds your shares, giving you the right to vote the shares at the special meeting.

The effect of not instructing your bank, broker or other nominee how you wish to vote your shares will be the same as a vote “ AGAINST ” the merger agreement proposal, but will not be counted as “ FOR ” or “ AGAINST ” and, assuming a quorum is present at the special meeting, will have NO EFFECT on, the compensation proposal or the adjournment proposal.

Record Holders . For shares held directly, please complete, sign, date and return each proxy card (or cast your vote by telephone or Internet as provided on each proxy card) or otherwise follow the voting instructions provided in this proxy statement in order to ensure that all of your shares of Versum common stock are voted.

Shares in “street name.” For shares held in “street name” through a bank, broker or other nominee, you should follow the procedures provided by your bank, broker or other nominee to vote your shares.

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Execution or revocation of a proxy will not in any way affect your right to attend the special meeting and vote in person. Written notices of revocation and other communications with respect to the revocation of proxies should be addressed to:

Versum Materials, Inc.

Attn: Corporate Secretary

8555 South River Parkway,

Tempe, Arizona 85284

For more information, see the section entitled “ The Special Meeting—Revocability of Proxies ” beginning on page 31.

If your shares are held in the name of a bank, broker or other nominee and you previously provided voting instructions to your bank, broker or other nominee, you should follow the instructions provided by your bank, broker or other nominee to revoke or change your voting instructions.

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However, in order to receive the merger consideration, you must hold your shares of Versum common stock through the completion of the merger. Consequently, if you transfer your shares of Versum common stock before completion of the merger, you will have transferred your right to receive the merger consideration.

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Innisfree M&A Incorporated

501 Madison Avenue, 20th Floor

New York, New York 10022

Toll-Free: (877) 456-3463

Call Collect: (212) 750-5833

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This proxy statement and the documents to which Versum refers you to in this proxy statement, as well as oral statements made or to be made by Versum, include certain “forward-looking statements” within the meaning of, and subject to the safe harbor created by, Section 21E of the Exchange Act and the Private Securities Litigation Reform Act of 1995. We intend for these forward-looking statements to be covered by the safe harbor provisions of the federal securities laws relating to forward-looking statements. Statements included in or incorporated by reference into this proxy statement, that are not historical facts are forward-looking statements, including statements about the beliefs and expectations of the management of Versum. Words such as “believe,” “continue,” “could,” “expect,” “anticipate,” “intends,” “estimate,” “forecast,” “project,” “should,” “may,” “will,” “would” or the negative thereof and similar expressions are intended to identify such forward-looking statements that are intended to be covered by the safe harbor provisions. Versum cautions investors that any forward-looking statements are subject to known and unknown risks and uncertainties, many of which are outside Versum’s control, and which may cause actual results and future trends to differ materially from those matters expressed in, or implied or projected by, such forward-looking statements, which speak only as of the date of this proxy statement. Investors are cautioned not to place undue reliance on these forward-looking statements. Among the risks and uncertainties that could cause actual results to differ from those described in forward-looking statements are the following:

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See the section entitled “ Where You Can Find More Information ” beginning on page 122 for more information about the SEC filings incorporated by reference into this proxy statement.

All subsequent written or oral forward-looking statements attributable to Versum or any person acting on its or their behalf are expressly qualified in their entirety by the cautionary statements contained or referred to in this section. Versum is under no obligation, and expressly disclaims any obligation, to update, alter, or otherwise revise any forward-looking statements, whether written or oral, that may be made from time to time, whether as a result of new information, future events or otherwise, except as may be required by law.

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THE PARTIES TO THE MERGER

Versum Materials, Inc.

8555 South River Parkway

Tempe, Arizona 85284

(602) 282-1000

Versum is a global provider of innovative solutions to the semiconductor and display industries with expertise in the development, manufacturing, transportation and handling of specialty materials. Versum employs expertise in molecular design and synthesis, purification, advanced analytics, formulation development and containers and delivery systems for the handling of high purity materials to deliver leading-edge solutions and critical process support to Versum’s customers.

Versum common stock is listed on the NYSE under the ticker symbol “VSM.”

For more information about Versum, please visit Versum’s website at http://www.versummaterials.com. The information contained on Versum’s website or accessible through it (other than the documents incorporated by reference herein) does not constitute a part of this proxy statement or any other report or document on file with or furnished to the SEC. Additional information about Versum is included in the documents incorporated by reference into this proxy statement. See the section entitled “ Where You Can Find More Information ” beginning on page 122.

Merck KGaA

Frankfurter Strasse 250

64293 Darmstadt, Germany

+49 (0) 6151-720

Parent is a publicly-traded leading science and technology company, which operates across healthcare, life sciences and performance materials, with major research and development centers in Darmstadt, Boston, Tokyo and Beijing.

Shares of Parent are listed on the Frankfurt Stock Exchange under the ticker symbol “MRK.”

For more information about Parent, please visit Parent’s website at http://www.emdgroup.com. The information contained on Parent’s website or accessible through it (other than the documents incorporated by reference herein) does not constitute a part of this proxy statement or any other report or document on file with or furnished to the SEC.

EMD Performance Materials Holding, Inc.

400 Summit Drive

Burlington, MA 01803

+49 (0) 6151-720

EMD Performance Materials Holding, Inc., or Merger Sub, was formed for the purpose of the acquisition of Versum, including the transactions contemplated by the merger agreement. Upon completion of the merger, Merger Sub will merge with and into Versum, with Merger Sub ceasing to exist and Versum surviving and continuing as the surviving corporation in the merger and a wholly-owned subsidiary of Parent. All of the outstanding shares of capital stock of Merger Sub are, and as of the effective date will be, owned directly or indirectly by Parent.

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THE SPECIAL MEETING

This proxy statement is first being mailed on or about May 14, 2019 and constitutes notice of the special meeting in conformity with the requirements of the DGCL and the amended and restated bylaws of Versum, which are referred to as the Versum bylaws.

This proxy statement is being provided to Versum stockholders as part of a solicitation of proxies by the Versum board of directors for use at the special meeting and at any adjournments or postponements of the special meeting. Versum stockholders are encouraged to read the entire document carefully, including the annexes to and documents incorporated by reference into this document, for more detailed information regarding the merger agreement and the transactions contemplated by the merger agreement.

Date, Time and Place of the Special Meeting

The special meeting is scheduled to be held at 8555 South River Parkway, Tempe, Arizona 85284, on June 17, 2019, beginning at 2:00 p.m., local time.

Matters to Be Considered at the Special Meeting

The purposes of the special meeting are as follows, each as further described in this proxy statement:

Recommendation of the Versum Board of Directors

The Versum board of directors unanimously recommends that Versum stockholders vote:

After careful consideration, the Versum board of directors unanimously (1) determined that the merger agreement, the merger and the other transactions contemplated by the merger agreement are fair to, and in the best interests of, Versum and its stockholders; (2) approved and declared advisable the merger agreement, the merger and the other transactions contemplated by the merger agreement; (3) directed that the merger agreement be submitted for adoption at a meeting of Versum stockholders; and (4) resolved to recommend that Versum stockholders vote in favor of the adoption of the merger agreement.

See also the section entitled “ The Merger—Recommendation of the Versum Board of Directors; Versum’s Reasons for the Merger ” beginning on page 42.

Record Date for the Special Meeting and Voting Rights

The record date to determine who is entitled to receive notice of and to vote at the special meeting or any adjournments or postponements thereof is May 13, 2019. As of the close of business on May 9, 2019, the latest practicable date prior to the date of this proxy statement, there were 109,240,997 shares of Versum common stock issued and outstanding and entitled to vote at the special meeting. Each Versum stockholder is entitled to

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one vote for any matter properly brought before the special meeting for each share of Versum common stock such holder owned at the close of business on the record date. Only Versum stockholders of record at the close of business on the record date are entitled to receive notice of and to vote at the special meeting and any and all adjournments or postponements thereof.

Quorum; Abstentions and Broker Non-Votes

A quorum of stockholders is necessary to conduct the special meeting. The presence, in person or by proxy, of the holders of a majority of the shares of Versum common stock entitled to vote at the special meeting is necessary to constitute a quorum. Shares of Versum common stock represented at the special meeting and entitled to vote, but not voted, including shares for which a stockholder directs an “abstention” from voting and broker non-votes, will be counted for purposes of determining a quorum. If a quorum is not present, the special meeting will be postponed until the holders of the number of shares of Versum common stock required to constitute a quorum attend.

Under the NYSE rules, banks, brokers or other nominees who hold shares in “street name” for a beneficial owner of those shares typically have the authority to vote in their discretion on “routine” proposals when they have not received instructions from beneficial owners. However, banks, brokers or other nominees are not allowed to exercise their voting discretion with respect to the approval of matters that the NYSE determines to be “non-routine.” Generally, a broker non-vote occurs on an item when (a) a bank, broker or other nominee has discretionary authority to vote on one or more “routine” proposals to be voted on at a meeting of stockholders, but is not permitted to vote on other “non-routine” proposals without instructions from the beneficial owner of the shares and (b) the beneficial owner fails to provide the bank, broker or other nominee with such instructions. Under the NYSE rules, “non-routine” matters include the merger agreement proposal (Proposal 1), the compensation proposal (Proposal 2) and the adjournment proposal (Proposal 3). Because none of the proposals currently scheduled to be voted on at the special meeting are routine matters for which brokers may have discretionary authority to vote, Versum expects there will not be the ability to vote any broker non-votes at the special meeting. As a result, if you hold your shares of Versum common stock in “street name,” your shares will not be represented and will not be voted on any matter unless you affirmatively instruct your bank, broker or other nominee how to vote your shares in one of the ways indicated by your bank, broker or other nominee. It is therefore critical that you cast your vote by instructing your bank, broker or other nominee on how to vote. The NYSE rules governing brokers’ discretionary authority will not permit brokers to exercise discretionary authority regarding any of the proposals to be voted on at the special meeting.

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As of May 9, 2019, the latest practicable date prior to the date of this proxy statement, Versum directors and executive officers, and their affiliates, as a group, owned and were entitled to vote 679,695 shares of Versum common stock, or approximately less than 1% of the total outstanding shares of Versum common stock. Although none of them has entered into any agreement obligating them to do so, Versum currently expects that all of its directors and executive officers will vote their shares “ FOR ” the merger agreement proposal, “ FOR ” the compensation proposal and “ FOR ” the adjournment proposal. See also the section entitled “ The Merger—Interests of Versum’s Directors And Executive Officers In The Merger ” beginning on page 64 and the arrangements described in Part III of Versum’s Annual Report on Form 10-K for the year ended September 30, 2018 and Versum’s Definitive Proxy Statement on Schedule 14A for Versum’s annual meeting filed with the SEC on December 20, 2018, both of which are incorporated into this proxy statement by reference.

As of May 9, 2019, the latest practicable date prior to the date of this proxy statement, Parent, Merger Sub and their subsidiaries, as a group, owned 100 shares of Versum common stock, or less than 0.1% of the total outstanding shares of Versum common stock.

Methods of Voting

If you are a stockholder of record, you may vote by proxy through the Internet, by telephone or by mail, or by voting in person at the special meeting. For shares held through a bank, broker or other nominee in “street name” instead of as a registered holder, you may vote by submitting your voting instructions to your bank, broker or other nominee. In most instances, you will be able to do this over the Internet, by telephone or by mail as indicated below. Please refer to the information from your bank, broker or other nominee on how to submit voting instructions. If you do not provide voting instructions to your bank, broker or other nominee, your shares of Versum common stock will not be voted on any proposal as your bank, broker or other nominee does not have

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discretionary authority to vote on any of the proposals to be voted on at the special meeting; see the section entitled “ The Special Meeting—Quorum; Abstentions and Broker Non-Votes ” beginning on page 29.

Unless revoked, all proxies representing shares entitled to vote that are delivered pursuant to this solicitation will be voted at the special meeting and, where a choice has been specified on the proxy card, will be voted in accordance with such specification. If you are a stockholder of record, proxies submitted over the Internet, by telephone or by mail as described above must be received by 11:59 p.m., Eastern Time, on June 16, 2019. To reduce administrative costs and help the environment by conserving natural resources, Versum asks that you vote through the Internet or by telephone, both of which are available 24 hours a day.

Notwithstanding the above, if you hold your shares in “street name” and you submit voting instructions to your bank, broker or other nominee, your instructions must be received by the bank, broker or other nominee prior to the deadline set forth in the information from your bank, broker or other nominee on how to submit voting instructions.

If you deliver a proxy pursuant to this proxy statement, but do not specify a choice with respect to any proposal set forth in this proxy statement, your underlying shares of Versum common stock will be voted on such uninstructed proposal in accordance with the recommendation of the Versum board of directors. Versum does not expect that any matter other than the proposals listed above will be brought before the special meeting and the Versum bylaws provide that the only business that may be conducted at the special meeting are those proposals brought before the meeting pursuant to this proxy statement.

Revocability of Proxies

Any stockholder giving a proxy has the right to revoke it before the proxy is voted at the special meeting by any of the following actions:

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Only your last submitted proxy card will be considered. Execution or revocation of a proxy will not in any way affect the stockholder’s right to attend the special meeting and vote in person.

Written notices of revocation and other communications with respect to the revocation of proxies should be addressed to:

Versum Materials, Inc.

Attn: Corporate Secretary

8555 South River Parkway

Tempe, Arizona 85284

If your shares are held in “street name” and you previously provided voting instructions to your broker, bank or other nominee, you should follow the instructions provided by your broker, bank or other nominee to revoke or change your voting instructions.

Proxy Solicitation Costs

Versum is soliciting proxies to provide an opportunity to all Versum stockholders to vote on agenda items, whether or not the stockholders are able to attend the special meeting or an adjournment or postponement thereof. Versum will bear the entire cost of soliciting proxies from its stockholders, except that Versum and Parent have agreed to each pay one half of the costs and expenses of filing, printing and mailing this proxy statement and all filing and other similar fees payable to the SEC in connection with this proxy statement. In addition to the solicitation of proxies by mail, Versum will request that banks, brokers and other nominee record holders send proxies and proxy material to the beneficial owners of Versum common stock and secure their voting instructions, if necessary. Versum may be required to reimburse those banks, brokers and other nominees on request for their reasonable expenses in taking those actions.

Versum has also retained Innisfree to assist in soliciting proxies and in communicating with Versum stockholders and estimates that it will pay them a fee of approximately $750,000 plus reimbursement for certain out-of-pocket fees and expenses (relating to this transaction and their work in connection with the Entegris merger). Versum also has agreed to indemnify Innisfree against various liabilities and expenses that relate to or arise out of its solicitation of proxies (subject to certain exceptions). Proxies may be solicited on behalf of Versum or by Versum directors, officers and other employees in person, by mail, by telephone, by facsimile, by messenger, via the Internet or by other means of communication, including electronic communication. Directors, officers and employees of Versum will not be paid any additional amounts for their services or solicitation in this regard.

Attending the Special Meeting

If you wish to attend the special meeting, you must be a stockholder of record of Versum at the close of business on May 13, 2019 (the record date for the special meeting), hold your shares of Versum beneficially in the name of a broker, bank or other nominee as of the record date or hold a valid proxy for the special meeting. If you hold your shares through a broker, bank or other nominee in “street name” (instead of as a registered holder) and you wish to vote in person at the special meeting, you must obtain a legal proxy from your bank, broker or other nominee and bring the legal proxy to the meeting in order to vote in person at the special meeting.

You will need to bring identification along with either your notice of special meeting or proof of stock ownership to enter the special meeting. If your Versum shares are beneficially held in the name of a broker, bank or other nominee and you wish to be admitted to attend the special meeting, you must present proof of your ownership of Versum shares, such as a bank or brokerage statement. The use of video, still photography or audio recording at the special meeting is not permitted. For the safety of attendees, all bags, packages and briefcases are subject to inspection. If you do not provide photo identification or comply with the other procedures outlined above, you might not be admitted to the special meeting.

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If you plan to attend the special meeting and vote in person, Versum still encourages you to vote in advance by the Internet, telephone or (if you received a paper copy of the proxy materials) by mail so that your vote will be counted even if you later decide not to attend the special meeting. Voting your proxy by the Internet, telephone or mail will not limit your right to vote at the special meeting if you later decide to attend in person.

Householding

SEC rules permit companies and intermediaries such as brokers to satisfy delivery requirements for proxy statements and notices with respect to two or more stockholders sharing the same address by delivering a single proxy statement or a single notice addressed to those stockholders. This process, which is commonly referred to as “householding,” provides cost savings for companies. Some brokers household proxy materials, delivering a single proxy statement or notice to multiple stockholders sharing an address unless contrary instructions have been received from the affected stockholders. Once you have received notice from your broker that they will be householding materials to your address, householding will continue until you are notified otherwise or until you revoke your consent. If, at any time, you no longer wish to participate in householding and would prefer to receive a separate proxy statement or notice, or if your household is receiving multiple copies of these documents and you wish to request that future deliveries be limited to a single copy, please notify your broker. You can request prompt delivery of a copy of this proxy statement by writing to: Corporate Secretary, Versum Materials, Inc., 8555 South River Parkway, Tempe, Arizona 85284 or by calling (602) 282-1000.

Tabulation of Votes

A representative of Versum’s mailing and tabulating agent, Broadridge, will tabulate the votes and Versum’s corporate secretary will serve as the inspector of election for the special meeting.

Adjournments

The special meeting may be adjourned if there are not sufficient votes at the time of the special meeting to approve the merger agreement proposal. When the special meeting is adjourned to another place, date or time, written notice need not be given of the adjourned meeting if the place, date and time thereof are announced at the meeting at which the adjournment is taken; provided, however, that if the date of any adjourned meeting is more than 30 days after the date for which the meeting was originally noticed, or if a new record date is fixed for the adjourned meeting, written notice of the place, date and time of the adjourned meeting will be given in conformity herewith.

At any subsequent reconvening of the special meeting at which a quorum is present, any business may be transacted that might have been transacted at the original meeting and all proxies will be voted in the same manner as they would have been voted at the original convening of the special meeting, except for any proxies that have been effectively revoked or withdrawn prior to the time the proxy is voted at the reconvened meeting.

Assistance

If you need assistance voting or in completing your proxy card or have questions regarding the special meeting, please contact Innisfree, the proxy solicitation agent for Versum:

Innisfree M&A Incorporated

501 Madison Avenue, 20th Floor

New York, New York 10022

Stockholders may call toll free: (877) 456-3463

Banks and brokers may call collect: (212) 750-5833

THE MERGER

The following is a description of material aspects of the merger. While Versum believes that the following description covers the material terms of the merger, the description may not contain all of the information that is important to you. You are encouraged to read carefully this entire proxy statement, including the text of the merger agreement attached to this proxy statement as Annex  A , for a more complete understanding of the merger. In addition, important business and financial information about Versum is included in or incorporated by reference into this proxy statement. See “ Where You Can Find More Information ” beginning on page 122.

General

Versum entered into the merger agreement with Parent and Merger Sub, which provides for the merger of Merger Sub with and into Versum. As a result of the merger, the separate existence of Merger Sub will cease and Versum will continue its existence under the laws of the State of Delaware as the surviving corporation and a wholly-owned subsidiary of Parent.

Merger Consideration

At the effective time, each share of Versum common stock (other than the Versum excluded shares) will be converted into the right to receive the merger consideration. After the merger is completed, holders of Versum common stock will have only the right to receive a cash payment in respect of their shares of Versum common stock, and will no longer have any rights as holders of Versum common stock, including voting or other rights.

Background of the Merger

The Versum board of directors and Versum’s senior management regularly review and assess Versum’s operations and financial performance, industry conditions and related developments as they may impact Versum’s long-term strategic plans and objectives. As part of this ongoing evaluation, following Versum’s spin-off from Air Products in 2016, the Versum board of directors, together with Versum’s senior management team, has from time to time considered various potential financial and strategic opportunities to enhance stockholder value.

In furtherance of Versum’s consideration of its strategic direction, Versum has periodically consulted with Lazard over the years, including without any formal engagements, for a number of reasons that include Lazard’s experience and expertise as a financial advisor in a wide variety of transactions and its familiarity with Versum’s business.

On December 8, 2018, Guillermo Novo, Versum’s president and chief executive officer, and Bertrand Loy, Entegris’ president and chief executive officer, met, at Mr. Novo’s invitation, in Tokyo, Japan. During this meeting, Mr. Novo raised the possibility of an all-stock merger of equals between Versum and Entegris. No specific transaction terms were proposed at this meeting. Following that meeting, Messrs. Novo and Loy remained in contact regarding a potential transaction between the two companies.

On January 3, 2019, Versum and Entegris entered into a mutual non-disclosure and standstill agreement allowing for confidential negotiations and due diligence investigations.

On January 4, 2019, Mr. Novo, Seifi Ghasemi, chairman of the Versum board of directors, Mr. Loy and Paul Olson, the chairman of the Entegris board of directors, met in New York City to continue to discuss a potential merger between Versum and Entegris. At the meeting, the parties discussed Versum’s and Entegris’ respective business philosophies, the parties’ mutual desire for an all-stock merger, potential transaction structures and potential governance and management of the combined company that would result from a merger between Versum and Entegris. During this meeting, Messrs. Loy and Olson proposed that Mr. Ghasemi would

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serve as the chairman of the board of the combined company following the Entegris merger, that Mr. Loy would serve as the chief executive officer of the combined company following the Entegris merger and that Gregory Graves, Entegris’ chief financial officer, would serve as the chief financial officer of the combined company following the Entegris merger.

On January 7, 2019, the Versum board of directors authorized the commencement of due diligence and from January 9 through January 27, 2019 Versum and Entegris engaged in mutual due diligence investigations of one another.

On January 12, 2019, at a telephonic meeting of the Versum board of directors, the Versum board of directors discussed, among other things, potential terms of a potential transaction with Entegris, including preliminary views on trading multiples, the potential exchange ratio and certain social issues. The Versum board of directors subsequently authorized Messrs. Novo and Ghasemi to negotiate the potential exchange ratio with representatives of Entegris based on historical trading multiple averages.

On January 17, 2019, prior to the meeting of Messrs. Ghasemi, Novo, Loy and Olson, representatives of Morgan Stanley & Co. LLC, Entegris’ financial advisor, provided representatives of Lazard with a summary of Entegris’ proposed key terms, including (i) as had been previously discussed between the parties, that Mr. Ghasemi serve as chairman of the board of directors of the combined company following the Entegris Merger, that Mr. Loy and Mr. Graves serve as the chief executive officer and chief financial officer of the combined company following the Entegris merger, respectively, and that the board of directors of the combined company include nine members, with four to be designated by Versum, four to be designated by Entegris, in addition to Mr. Loy as chief executive officer of the combined company following the Entegris merger and (ii) an exchange ratio of 1.097, meaning Versum stockholders would receive 1.097 shares of Entegris’ common stock, par value $0.01 per share, which is referred to as Entegris common stock, for each share of Versum common stock held.

Later that day, on January 17, 2019, Messrs. Novo, Ghasemi, Loy and Olson met in Scottsdale, Arizona to discuss the potential transaction between Versum and Entegris and certain key terms. The parties confirmed their continued belief that a merger of the two companies would be beneficial to both Entegris, Versum and their respective stockholders, and reached agreement, subject in both cases to board approval, as to certain terms regarding the governance of the combined company following the Entegris merger. After negotiation during the meeting, the participants agreed to recommend to their respective boards of directors an exchange ratio of 1.120 shares of Entegris common stock to be exchanged for each share of Versum common stock. The Versum board of directors met on January 18 and January 24, 2019, at which meetings, among other things, the Versum board of directors received and discussed updates on the ongoing discussions and negotiations regarding a potential transaction with Entegris, including the potential exchange ratio and certain social issues.

From January 18 through January 27, 2019, Entegris, Versum and their respective financial and legal advisors continued to conduct due diligence on each other and the parties negotiated the terms of the Entegris merger agreement, and ancillary documents and confirmed that Mr. Ghasemi would serve as the chairman of the board of directors of the combined company following the Entegris merger, Mr. Loy would serve as the chief executive officer of the combined company, Mr. Graves would serve as the chief financial officer of the combined company following the Entegris merger and Michael Valente, the general counsel of Versum, would serve as the general counsel of the combined company following the Entegris merger. Both companies held several board meetings with their financial and legal advisors and management during this period.

On January 27, 2019, the Entegris board of directors unanimously approved the Entegris merger agreement, the Entegris merger and the transactions contemplated thereby and resolved to recommend that the holders of shares of Entegris common stock vote in favor of the adoption of the Entegris merger agreement and related matters. Later on the same day, a meeting of the Versum board of directors was held in Scottsdale, Arizona. Mr. Ghasemi updated the Versum board of directors on the status of the negotiations with Entegris and reported

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that the Entegris board of directors had unanimously resolved to approve the potential transaction. A representative of Simpson Thacher & Bartlett LLP, Versum’s legal advisor, which is referred to as Simpson Thacher, reviewed with the Versum board of directors their fiduciary duties under applicable law and the terms of the draft Entegris merger agreement. Representatives of Lazard then reviewed with the Versum board of directors Lazard’s financial analysis of the potential transaction with Entegris. Following further discussion, representatives of Lazard then delivered to the Versum board of directors Lazard’s oral opinion, subsequently confirmed in writing by delivery of Lazard’s opinion dated as of the same date, to the effect that, as of such date, and based upon and subject to the assumptions, procedures, factors, qualifications and limitations set forth in Lazard’s written opinion, the exchange ratio of 1.120 shares of Entegris common stock per share of Versum common stock was fair, from a financial point of view, to the Versum stockholders (other than the holders of Versum excluded shares). After discussions, the Versum board of directors unanimously approved the Entegris merger agreement, the Entegris merger and the transactions contemplated thereby, directed that the Entegris merger agreement be submitted for adoption at a meeting of Versum stockholders and resolved to recommend that the Versum stockholders vote in favor of the adoption of the Entegris merger agreement.

Following the approval of the Entegris merger and the Entegris merger agreement by the Entegris board of directors and the Versum board of directors, Entegris and Versum finalized and executed the Entegris merger agreement on January 27, 2019, and in the morning of January 28, 2019, prior to the opening of trading, issued a joint press release announcing the execution of the Entegris merger agreement.

On February 27, 2019, Dr. Stefan Oschmann, chief executive officer of Parent, placed a call to Mr. Ghasemi to inform him of Parent’s interest in acquiring Versum. Mr. Ghasemi responded that he would discuss the call with the members of the Versum board of directors. Within minutes after such call, on February 27, 2019, Parent sent a letter to the Versum board of directors setting forth a non-binding unsolicited proposal to acquire Versum for $48.00 per share in cash, which is referred to as the initial Parent proposal. In the letter, Parent stated that Parent was required by law to disclose the initial Parent proposal publicly and simultaneously with the delivery of it to Versum.

Later that morning on February 27, 2019, Versum issued a press release that acknowledged receipt of the initial Parent proposal and stated that Versum continues to believe in the strategic and financial rationale of the proposed merger of equals with Entegris and that the Versum board of directors intends to thoroughly review the initial Parent proposal consistent with its fiduciary duties.

On February 27, 2019, the Versum board of directors met telephonically, together with members of Versum’s senior management and representatives of Lazard and Simpson Thacher, to discuss next steps in connection with the review of the initial Parent proposal. After that meeting on February 27, 2019, Entegris issued a press release in response to the initial Parent proposal, stating that Entegris believes the merger of Versum and Entegris will deliver meaningful value to Versum stockholders and Entegris stockholders.

On February 28, 2019, the Versum board of directors met via a telephonic meeting, at which representatives of Versum’s senior management, Lazard and Simpson Thacher were present. Following discussion of the initial Parent proposal and, in light of recent unusual trading activity in the stock of Versum, the Versum board of directors resolved to adopt a limited duration shareholder rights plan, which is referred to as the Versum rights plan, which the Versum board of directors had previously reviewed with Simpson Thacher and which was available to be implemented quickly in response to a specific threat to corporate policymaking, such as the decision to pursue the Entegris merger. Later on February 28, 2019, the Versum board of directors authorized and declared a dividend of one preferred share purchase right for each outstanding share of Versum common stock, payable to Versum stockholders of record on March 11, 2019, pursuant to the Versum rights plan.

On March 1, 2019, the Versum board of directors met telephonically, together with members of Versum’s senior management and representatives of Lazard and Simpson Thacher, to discuss the initial Parent proposal. Representatives of Lazard reviewed with the Versum board of directors Lazard’s financial analysis of the initial

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Parent proposal. Members of the Versum board of directors then discussed the terms of the initial Parent proposal and the Entegris merger agreement, consulted with representatives of Versum senior management, Lazard and Simpson Thacher, and concluded, after careful review and consideration, that the initial Parent proposal was not a superior proposal for purposes of the Entegris merger agreement. Later that day on March 1, 2019, Versum issued a press release announcing the determination by the Versum board of directors, and stating that Versum remained committed to completing the merger with Entegris, which the Versum board of directors believed will create significant long-term value, and is in the best interests of the Versum stockholders.

On March 2, 2019, the Versum board of directors met telephonically with members of Versum’s senior management and representatives of Simpson Thacher to discuss the desirability of obtaining advice from an additional financial advisor in connection with the initial Parent proposal. Following discussion, the Versum board of directors instructed Versum’s senior management to seek to engage Citi to advise the Versum board of directors with respect to a financial analysis of the initial Parent proposal. Citi was selected on the basis of its experience in the industries in which Versum operates and its familiarity with Versum.

On March 4, 2019, representatives of Parent and its financial advisor proposed to arrange a telephone call between Dr. Oschmann of Parent and Mr. Ghasemi, which Mr. Ghasemi declined following consultation with members of Versum’s senior management and representatives of Simpson Thacher, consistent with the terms of the Entegris merger agreement.

On March 5, 2019, Parent issued an open letter to the Versum stockholders, stating that Parent remains fully committed to pursuing the initial Parent proposal and requesting that the Versum board of directors engage with Parent.

On March 6, 2019, the Versum board of directors met telephonically, together with members of Versum’s senior management and representatives of Citi and Simpson Thacher, to discuss the initial Parent proposal. At the meeting, representatives of Versum’s senior management updated the Versum board of directors on the status of the integration planning meetings between the management teams of Versum and Entegris and the identification of potential additional synergies resulting from the Entegris merger. Representatives of Citi presented to the Versum board of directors Citi’s preliminary financial analysis. Following discussion of the initial Parent proposal and the Entegris merger with representatives of Versum’s senior management, Citi and Simpson Thacher, the Versum board of directors reaffirmed, after careful review and consideration, its previous determination that the initial Parent proposal was not a superior proposal for purposes of the Entegris merger agreement.

On March 8, 2019, Versum and Entegris issued a joint open letter to Versum stockholders and Entegris stockholders, reiterating the value-creation potential and strategic benefits of the Entegris merger and announcing additional expected synergies resulting from the Entegris merger.

Also on March 8, 2019, the Versum board of directors issued a statement reiterating its determination that the initial Parent proposal was not a superior proposal for purposes of the Entegris merger agreement, and reaffirming its commitment to completing the Entegris merger.

On March 11, 2019, Entegris and Versum announced the expiration of the waiting period under the HSR Act, in connection with the Entegris merger, which occurred at 11:59 p.m. EST on March 8, 2019 and satisfied one of the conditions to closing of the Entegris merger.

On March 12, 2019, Parent filed a preliminary proxy statement with the SEC with respect to the solicitation of proxies by Parent in opposition to the Entegris merger.

On March 14, 2019, Versum announced that it had entered into an amendment to the Versum rights plan to remove references to the defined concept of “Acting in Concert” from the Versum rights plan.

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On March 20, 2019, Versum filed a definitive joint proxy statement/prospectus on Schedule 14A with the SEC with respect to the Entegris merger.

On March 21, 2019, Versum issued a press release announcing the commencement of mailing on or about March 22, 2019 of the definitive joint proxy statement/prospectus to Versum stockholders, relating to a special meeting of Versum stockholders to be held on April 26, 2019, to consider the Entegris merger.

On March 22, 2019, a meeting of the Versum board of directors, at which representatives of Versum’s senior management, Lazard, Citi, Simpson Thacher and Innisfree were present, was held in New York, New York. Mr. Loy was also present for a portion of the meeting. At this meeting, Mr. Loy discussed with members of the Versum board of directors and Versum’s senior management his perspective concerning the value maximizing opportunity for the stockholders of Versum and Entegris in pursuing the Entegris merger. After Mr. Loy departed, representatives of Lazard reviewed with the Versum board of directors Lazard’s financial analysis of the Entegris merger and the initial Parent proposal, representatives of Citi reviewed with the Versum board of directors Citi’s financial analysis of the Entegris merger and the initial Parent proposal, representatives of Simpson Thacher reviewed with the members of the Versum board of directors their fiduciary duties under applicable law and representatives of Innisfree discussed with the Versum board of directors Innisfree’s analysis of the upcoming vote of Versum stockholders at the special meeting of Versum stockholders with respect to the Entegris merger. The Versum board of directors discussed next steps with management and Versum’s financial and legal advisors.

Also on March 22, 2019, Parent filed a definitive proxy statement with the SEC with respect to the solicitation of proxies by Parent in opposition to the Entegris merger.

On March 26, 2019, Parent filed with the SEC a Schedule TO and issued a press release announcing that it had commenced a tender offer to purchase all outstanding shares of Versum common stock at $48.00 per share, which is referred to as the Parent tender offer.

Later on March 26, 2019, Versum issued a press release noting that the Versum board of directors would review the Parent tender offer and intended to advise Versum stockholders of its formal position regarding the Parent tender offer within 10 business days by making available to Versum stockholders and filing with the SEC a solicitation/recommendation statement on Schedule 14D-9, and advised its stockholders to take no action at the time in response to the Parent tender offer.

In response to Parent’s publicly stated position that Parent would prefer to engage directly with the Versum board of directors, on March 27, 2019, Versum and Entegris entered into a waiver letter that permitted Versum to engage in discussions with, but not disclose non-public information to, Parent for a 10-day period from the date of such waiver letter.

Later that day, Mr. Ghasemi contacted Dr. Oschmann of Parent to schedule a meeting to discuss the initial Parent proposal and the Parent tender offer.

On March 28, 2019, Mr. Ghasemi and Dr. Oschmann met to discuss the terms of the initial Parent proposal and the Parent tender offer, and Dr. Oschmann conveyed the possibility that Parent would improve the terms of the Parent tender offer upon review by Parent of certain information required for Parent to complete its due diligence.

On March 28, 2019, the Versum board of directors held a telephonic meeting with members of Versum management and representatives of Lazard, Citi and Simpson Thacher in attendance. Representatives of Lazard and Citi confirmed with the Versum board of directors that their respective financial analyses of the initial Parent proposal applied equally to the Parent tender offer price. Representatives of Simpson Thacher reviewed with the members of the Versum board of directors their fiduciary duties under applicable law. The Versum board of

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directors discussed and considered the terms of the Parent tender offer with management and Versum’s financial and legal advisors. Thereafter, the Versum board of directors unanimously determined that the Parent tender offer did not constitute a superior proposal under the terms of the Entegris merger agreement and was not in the best interests of Versum and its stockholders, recommended that Versum stockholders reject the Parent tender offer and not tender their shares of Versum common stock into the Parent tender offer, and reaffirmed the Versum board of directors’ recommendation in favor of the Entegris merger and the transactions contemplated by the Entegris merger agreement. Upon consideration of the March 28, 2019 meeting between Mr. Ghasemi and Dr. Oschmann, the Versum board of directors also unanimously determined, after consultation with its financial and legal advisors, that the initial Parent proposal and the Parent tender offer could reasonably be expected to result in a superior proposal for purposes of the Entegris merger agreement, and authorized Versum’s management and its advisors to engage in further discussions with, and provide non-public information to, Parent.

On March 29, 2019, Versum filed with the SEC a response to the Parent tender offer on a Schedule 14D-9 and issued a press release announcing that the Versum board of directors had unanimously determined to reject the Parent tender offer, unanimously determined that the initial Parent proposal could reasonably be expected to result in a superior proposal for purposes of the Entegris merger agreement, and authorized Versum’s management and its advisors to engage in further discussions with, and provide non-public information to, Parent.

On March 29, 2019, Versum and Parent entered into a confidentiality agreement and Versum provided Parent with access to certain nonpublic due diligence materials.

On March 31, 2019, Versum and plaintiffs in two previously disclosed putative class action lawsuits filed by certain purported stockholders of Versum seeking, among other things, relief declaring that the Versum rights plan was unenforceable and seeking to enjoin the Entegris merger, executed a stipulation dated as of March 31, 2019, pursuant to which such plaintiffs agreed to withdraw their motion seeking to enjoin consummation of the Entegris merger and related expedited discovery demands upon termination of the Versum rights plan.

On April 1, 2019 and April 2, 2019, representatives of Versum held meetings with representatives of Parent, at which representatives of Lazard and Citi and representatives of Guggenheim Securities, LLC, which is referred to as Guggenheim, and Goldman Sachs & Co., which is referred to as Goldman, Parent’s financial advisors, were present, in connection with a due diligence investigation of Versum by Parent.

On April 2, 2019, Versum entered into a rights agreement termination agreement with Broadridge amending the Versum rights plan by accelerating the definition of “Final Expiration Date” from August 30, 2019 to April 2, 2019, such that, as of 11:59 p.m. New York City time on April 2, 2019, the Rights issued pursuant to the Rights Agreement would expire and no longer be outstanding and the Rights Agreement would terminate and be of no further force and effect. Versum also issued a press release announcing the filing of the investor presentation with the SEC on April 1, 2019, and announcing that the Versum board of directors sent a letter to Versum stockholders regarding the Entegris merger, urging Versum stockholders to vote “FOR” the Entegris merger agreement at the special meeting of Versum stockholders with respect to the Entegris merger.

In the late evening on April 2, 2019, at the instruction of Parent, Sullivan & Cromwell LLP, Parent’s legal advisor, which is referred to as Sullivan & Cromwell, provided an initial draft of the Parent merger agreement to Simpson Thacher.

On April 3, 2019, Mr. Ghasemi and Dr. Oschmann met in New York, New York to discuss the Parent tender offer and the status of Parent’s due diligence investigation, and Dr. Oschmann suggested a follow-up meeting later that week.

On April 4, 2019, Messrs. Ghasemi and Loy met in New York, New York with representatives of Simpson Thacher and Wachtell, Lipton, Rosen & Katz, which is referred to as Wachtell Lipton, Entegris’ legal advisor, to discuss the Entegris merger and the Parent tender offer.

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On April 6, 2019, Mr. Ghasemi and Dr. Oschmann met in Munich, Germany. At this meeting, Dr. Oschmann informed Mr. Ghasemi that Parent would be willing to enter into a merger agreement with Versum on substantially the terms reflected in the previously provided draft of the merger agreement, and providing for a merger consideration of $53.00 in cash per share of Versum common stock, which is referred to as the revised Parent proposal.

On April 6, 2019, pursuant to the requirements of the Entegris merger agreement, Versum informed Entegris of the receipt of the revised Parent proposal. Also on April 6, 2019, and on numerous earlier occasions since the receipt of the initial Parent proposal, Versum requested that Entegris consider making a revised offer.

Also on April 6, 2019, at the instruction of Versum, representatives of Simpson Thacher sent a revised draft of the merger agreement to Sullivan & Cromwell.

On April 7, 2019, Sullivan & Cromwell and Simpson Thacher exchanged comments on, and discussed, the draft Parent merger agreement. Parent then submitted a proposal to Versum to acquire Versum for $53.00 per share of Versum common stock pursuant to an enclosed draft of the Parent merger agreement.

In the evening of April 7, 2019, at the instruction of Entegris, representatives of Wachtell Lipton sent a written proposal to representatives of Simpson Thacher, which is referred to as the revised Entegris proposal, pursuant to which, if the termination fee payable by Versum were increased to $215 million, Entegris would agree to certain amendments to the Entegris merger agreement, including an increase in the exchange ratio to 1.236 and the provision of $5 per share in cash consideration to Versum stockholders, and informed representatives of Simpson Thacher that the proposal would automatically be withdrawn if not accepted by midnight that day.

Later in the evening on April 7, 2019, the Versum board of directors met telephonically, together with members of Versum’s senior management and representatives of Lazard, Citi and Simpson Thacher, to discuss the revised Parent proposal and the revised Entegris proposal. Representatives of Simpson Thacher reviewed with the members of the Versum board of directors their fiduciary duties under applicable law. The Versum board of directors discussed and considered the terms of the revised Parent proposal and the revised Entegris proposal with management and Versum’s financial and legal advisors. The Versum board of directors also discussed with its advisors the fact that the revised Entegris proposal had been received less than two hours earlier and was set to expire at midnight, the Versum board of directors’ view that, based on the most recent closing price of Entegris common stock the revised Entegris proposal was lower on its face than the revised Parent proposal, the Versum board of directors’ expectation, upon consultation with Versum’s financial advisors, that the increased exchange ratio and the inclusion of cash consideration would likely adversely impact the price of Entegris common stock, and the fact that the Entegris merger agreement would entitle Entegris to a four business day “match” period, during which Entegris would have an opportunity to make any bona fide proposal to amend the Entegris merger agreement and to provide the Versum board of directors and its advisors with sufficient time to review the terms of any such proposal. Representatives of Lazard reviewed with the Versum board of directors Lazard’s preliminary financial analysis of the revised Parent proposal. Representatives of Citi reviewed with the Versum board of directors Citi’s preliminary financial analysis of the revised Parent proposal. Following discussion of the revised Parent proposal and the Entegris merger with representatives of Versum’s senior management, Lazard, Citi and Simpson Thacher, the Versum board of directors determined, after careful review and consideration, that the revised Parent proposal constituted a “Superior Proposal” as defined in the Entegris merger agreement and instructed Versum’s management and advisors to notify Entegris that the Versum board of directors had made such determination and that the Versum board of directors intended to consider whether to terminate the Entegris merger agreement pursuant to its terms to enter into a definitive merger agreement with respect to the revised Parent proposal. The Versum board of directors also authorized Versum’s management and advisors to negotiate with Entegris (to the extent Entegris wished to negotiate) during the four business day period ending on April 11, 2019 as required by the Entegris merger agreement, pursuant to which Entegris had the right to propose revisions to the Entegris merger agreement during this period, and instructed

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Versum’s management and advisors to inform the Versum board of directors of any proposals received from Entegris during such period. Later on April 7, 2019, representatives of Simpson Thacher notified Entegris of this determination.

On April 8, 2019, Versum issued a press release announcing that the Versum board of directors had determined that the revised Parent proposal constituted a “Superior Proposal” as defined in the Entegris merger agreement. Later on April 8, 2019, Entegris issued a statement that Entegris did not currently intend to propose to revise the terms of the Entegris merger.

On April 10, 2019, the applicable waiting period under the HSR Act in connection with the Parent tender offer expired.

On April 11, 2019, the Versum board of directors held a telephonic meeting, at which representatives of Versum’s senior management, Lazard, Citi and Simpson Thacher, were present. Mr. Ghasemi updated the Versum board of directors on the status of the negotiations with Parent, including that the parties had resolved all significant open substantive issues with respect to the terms of the potential transaction with Parent. The Versum board of directors also discussed with its legal and financial advisors that Entegris had not proposed any amendments to the Entegris merger agreement during the four business day “match” period. Representatives of Lazard then reviewed with the Versum board of directors Lazard’s financial analysis of the potential transaction with Parent. Following further discussion, representatives of Lazard then delivered to the Versum board of directors Lazard’s oral opinion, subsequently confirmed in writing by delivery of Lazard’s opinion dated as of the same date, to the effect that, as of such date, and based upon and subject to the assumptions, procedures, factors, qualifications and limitations set forth in Lazard’s written opinion, the merger consideration of $53.00 per share of Versum common stock was fair, from a financial point of view, to the Versum stockholders (other than the holders of Versum excluded shares). Representatives of Citi then reviewed with the Versum board of directors Citi’s financial analysis of the potential transaction with Parent. Following further discussion, representatives of Citi then delivered to the Versum board of directors Citi’s oral opinion, subsequently confirmed in writing by delivery of Citi’s opinion dated as of the same date, to the effect that, as of such date, and based upon and subject to the assumptions, procedures, factors, qualifications and limitations set forth in Citi’s written opinion, the merger consideration of $53.00 per share of Versum common stock was fair, from a financial point of view, to the Versum stockholders (other than the holders of treasury shares and Parent owned shares). Representatives of Simpson Thacher then reviewed with the Versum board of directors their fiduciary duties under applicable law and the terms of the Parent merger agreement.

After discussions, the Versum board of directors unanimously determined that the Parent merger agreement, the Parent merger and the other transactions contemplated by the Parent merger agreement were fair to, and in the best interests of, Versum and its stockholders, and continued to constitute a superior proposal for purposes of the Entegris merger agreement. The Versum board of directors approved the termination of the Entegris merger agreement and payment of the Entegris termination fee to Entegris, and approved and declared advisable the Parent merger agreement, the Parent merger and the other transactions contemplated by the merger agreement with Parent, directed that the merger agreement be submitted for adoption at a meeting of Versum stockholders and resolved to recommend that the Versum stockholders vote in favor of the adoption of the Parent merger agreement.

Following the approval of the Parent merger and the Parent merger agreement by the Versum board of directors, Parent and Versum finalized the Parent merger agreement.

In the morning of April 12, 2019, prior to the opening of trading, at the instruction of the Versum board of directors, representatives of Simpson Thacher sent a notice to Entegris terminating the Entegris merger agreement. Concurrently with the delivery of the termination notice, Versum paid the Entegris termination fee of $140 million pursuant to the Entegris merger agreement to Entegris, and Parent and Versum executed the Parent merger agreement. Shortly thereafter, on April 12, 2019, Versum and Parent issued a joint press release

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announcing the termination of the Entegris merger agreement and execution of the Parent merger agreement. Parent then filed a final amendment to the previously filed Schedule TO for the Parent tender offer, announcing the termination of the Parent tender offer.

Recommendation of the Versum Board of Directors; Versum’s Reasons for the Merger

At a meeting held on April 11, 2019, the Versum board of directors unanimously:

ACCORDINGLY, THE VERSUM BOARD OF DIRECTORS HAS APPROVED THE MERGER AGREEMENT AND UNANIMOUSLY RECOMMENDS THAT VERSUM STOCKHOLDERS VOTE “FOR” THE PROPOSAL TO ADOPT THE MERGER AGREEMENT.

In reaching its decision to approve and declare advisable the merger agreement, the merger and the other transactions contemplated by the merger agreement, the Versum board of directors, as described in the section entitled “— Background of the Merger ” beginning on page 34, held a number of meetings, consulted with Versum’s senior management and its outside legal and financial advisors, Simpson Thacher and Lazard and Citi, respectively, and considered the business, assets and liabilities, results of operations, financial performance, strategic direction and prospects of Versum. At its meeting held on April 11, 2019, after due consideration and consultation with Versum’s senior management and outside legal and financial advisors, the Versum board of directors unanimously approved and declared advisable the merger agreement, the merger and the other transactions contemplated by the merger agreement and recommended that Versum stockholders vote in favor of the adoption of the merger agreement.

In making its determination, the Versum board of directors focused on a number of factors, including the following:

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The Versum board of directors weighed these advantages and opportunities against a number of potentially negative factors in its deliberations concerning the merger agreement and the merger, including:

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The Versum board of directors considered all of these factors as a whole and, on balance, concluded that it supported a favorable determination to approve the merger agreement and to make its recommendations to Versum stockholders.

In addition, the Versum board of directors was aware of and considered the interests of its directors and executive officers that are different from, or in addition to, the interests of Versum stockholders generally, including the treatment of equity awards held by such directors and executive officers in the merger, the obligation of the combined company to indemnify Versum directors and officers against certain claims and liabilities, the payment of severance benefits and acceleration of outstanding equity awards upon certain terminations of employment or service, and the payment of retention bonuses described in the section entitled “ —Interests of Versum’s Directors and Executive Officers in the Merger ” beginning on page 64.

The foregoing discussion of the information and factors that the Versum board of directors considered is not intended to be exhaustive, but rather is meant to include the material factors that the Versum board of directors considered. The Versum board of directors collectively reached the conclusion to approve the merger agreement, the merger and the other transactions contemplated by the merger agreement in light of the various factors described above and other factors that the members of the Versum board of directors believed were appropriate. In view of the complexity and wide variety of factors, both positive and negative, that the Versum board of directors considered in connection with its evaluation of the merger, the Versum board of directors did not find it practical, and did not attempt, to quantify, rank or otherwise assign relative or specific weights or values to any of the factors it considered in reaching its decision and did not undertake to make any specific determination as to whether any particular factor, or any aspect of any particular factor, was favorable or unfavorable to the ultimate determination of the Versum board of directors. In considering the factors discussed above, individual directors may have given different weights to different factors.

The foregoing description of Versum’s consideration of the factors supporting the merger is forward-looking in nature. This information should be read in light of the factors discussed in the section entitled “ Cautionary Statement Regarding Forward-Looking Statements ” beginning on page 25.

Opinion of Versum’s Financial Advisors

Opinion of Lazard Frères & Co. LLC

Versum retained Lazard to act as its financial advisor in connection with the merger. As part of this engagement, Versum requested that Lazard evaluate the fairness, from a financial point of view, to Versum stockholders (other than holders of Versum excluded shares) of the consideration. At a meeting of the Versum board of directors held to evaluate the merger on April 11, 2019, Lazard rendered an oral opinion to the Versum board of directors, subsequently confirmed in writing by delivery of Lazard’s opinion dated as of the same date, to the effect that, as of such date, and based upon and subject to the assumptions, procedures, factors, qualifications and limitations set forth in Lazard’s written opinion, the consideration was fair, from a financial point of view, to Versum stockholders (other than the holders of Versum excluded shares).

The full text of Lazard’s written opinion, dated April 11, 2019, which sets forth the assumptions made, procedures followed, factors considered and qualifications and limitations on the review undertaken by Lazard in

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connection with its opinion, is attached as Annex B to this proxy statement and is incorporated herein by reference. We encourage you to read Lazard’s opinion carefully and in its entirety. Lazard’s opinion was provided for the use and benefit of the Versum board of directors (in its capacity as such) in its evaluation of the merger, and addressed only the fairness, as of the date of the opinion, from a financial point of view, to Versum stockholders (other than the holders of Versum excluded shares) of the consideration provided for in the merger. Lazard’s opinion is not intended to and does not constitute a recommendation to any stockholder as to how such stockholder should vote or act with respect to the merger or any matter relating thereto.

Lazard’s opinion was necessarily based on economic, monetary, market and other conditions as in effect on, and the information made available to Lazard as of, the date of Lazard’s opinion. Lazard assumed no responsibility for updating or revising its opinion based on circumstances or events occurring after the date of Lazard’s opinion. Lazard’s opinion did not express any opinion as to the price at which shares of Versum common stock may trade at any time subsequent to the announcement of the merger. In connection with its engagement, Lazard was not authorized to, and Lazard did not, solicit indications of interest from third parties regarding a potential transaction with Versum. In addition, Lazard’s opinion does not address the relative merits of the merger as compared to any other transaction or business strategy in which Versum might engage or the merits of the underlying decision by Versum to engage in the merger.

In connection with its opinion, Lazard:

Lazard assumed and relied upon the accuracy and completeness of the foregoing information, without independent verification of such information. Lazard has not conducted any independent valuation or appraisal of any of the assets or liabilities (contingent or otherwise) of Versum or concerning the solvency or fair value of Versum, and Lazard has not been furnished with any such valuation or appraisal. With respect to the financial forecasts utilized in Lazard’s analyses, including the extrapolations, Lazard assumed, with the consent of Versum, that they have been reasonably prepared on bases reflecting the best currently available estimates and judgments as to the future financial performance of Versum. Lazard assumed no responsibility for and expressed no view as to any such forecasts or the assumptions on which they are based.

In rendering its opinion, Lazard assumed, with the consent of Versum, that the merger will be consummated on the terms described in the merger agreement, without any waiver or modification of any material terms or conditions. Representatives of Versum have advised Lazard, and Lazard assumed, that the executed merger agreement conforms to the execution version reviewed by Lazard in all material respects. Lazard also assumed, with the consent of Versum, that obtaining the necessary governmental, regulatory or third party approvals and consents for the merger will not have an adverse effect on Versum or the merger that is material in any respect to

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Lazard’s analysis in connection with its opinion. Lazard did not express any opinion as to any tax or other consequences that might result from the merger, nor does Lazard’s opinion address any legal, tax, regulatory or accounting matters, as to which Lazard understood that Versum obtained such advice as it deemed necessary from qualified professionals. Lazard expressed no view or opinion as to any terms or other aspects (other than the consideration to the extent expressly specified herein) of the merger, including, without limitation, the form or structure of the merger or any agreements or arrangements entered into in connection with, or contemplated by, the merger. In addition, Lazard expressed no view or opinion as to the fairness of the amount or nature of, or any other aspects relating to, the compensation to any officers, directors or employees of any parties to the merger, or class of such persons, relative to the consideration or otherwise.

Summary of Lazard’s Financial Analyses

The following is a summary of the material financial analyses reviewed with the Versum board of directors in connection with Lazard’s opinion, dated April 11, 2019. The summary of Lazard’s analyses and reviews provided below is not a complete description of the analyses and reviews underlying Lazard’s opinion. The preparation of a fairness opinion is a complex process involving various determinations as to the most appropriate and relevant methods of analysis and review and the application of those methods to particular circumstances, and, therefore, is not readily susceptible to summary description.

In arriving at its opinion, Lazard did not draw, in isolation, conclusions from or with regard to any particular factor or analysis considered by it. Rather, Lazard made its determination as to fairness on the basis of its experience and professional judgment after considering the results of all of the analyses. Considering selected portions of the analyses and reviews in the summary set forth below, without considering the analyses and reviews as a whole, could create an incomplete or misleading view of the analyses and reviews underlying Lazard’s opinion.

For purposes of its analyses and reviews, Lazard considered industry performance, general business, economic, market and financial conditions and other matters, many of which are beyond the control of Versum. No company or business used in Lazard’s analyses and reviews as a comparison is identical to Versum, and an evaluation of the results of those analyses and reviews is not entirely mathematical. Rather, the analyses and reviews involve complex considerations and judgments concerning financial and operating characteristics and other factors that could affect the acquisition, public trading or other values of the companies or businesses used in Lazard’s analyses and reviews. The estimates contained in Lazard’s analyses and reviews and the ranges of valuations resulting from any particular analysis or review are not necessarily indicative of actual values or predictive of future results or values, which may be significantly more or less favorable than those suggested by Lazard’s analyses and reviews. In addition, analyses and reviews relating to the value of companies, businesses or securities do not purport to be appraisals or to reflect the prices at which companies, businesses or securities actually may be sold. Accordingly, the estimates used in, and the results derived from, Lazard’s analyses and reviews are inherently subject to substantial uncertainty.

The summary of the analyses and reviews provided below includes information presented in tabular format. In order to fully understand Lazard’s analyses and reviews, the tables must be read together with the full text of each summary. The tables alone do not constitute a complete description of Lazard’s analyses and reviews. Considering the data in the tables below without considering the full description of the analyses and reviews, including the methodologies and assumptions underlying the analyses and reviews, could create a misleading or incomplete view of Lazard’s analyses and reviews.

Except as otherwise noted, the following quantitative information, to the extent that it is based on market data, is based on market data as it existed on or before April 8, 2019, and is not necessarily indicative of current market conditions.

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Financial Analysis

Public Trading Valuation Analysis

Overview

Lazard reviewed and analyzed certain financial information, valuation multiples and market trading data related to Cabot Microelectronics Corporation, which is referred to as Cabot Microelectronics, Entegris and Versum. Lazard reviewed and analyzed such information because it believed, based on its judgment and experience, Cabot Microelectronics and Entegris to be similar to Versum’s operations for purposes of these analyses. Although Cabot Microelectronics and Entegris are not identical or directly comparable to Versum, they were chosen because they are publicly traded companies with certain operations, results, business mixes or product profiles that, for the purposes of analysis, may be considered similar to certain operations, results, business mixes or product profile of Versum.

EV / EBITDA Analysis

Lazard reviewed EV / EBITDA multiples of Versum and Entegris as of January 25, 2019 (the last trading day prior to the announcement of the Entegris merger) based on (1) trading prices on January 25, 2019, (2) 10-trading day volume-weighted average prices as of January 25, 2019 and (3) 20-trading day volume-weighted average prices as of January 25, 2019. Lazard observed a high correlation between the stock prices of Versum and Entegris and the Philadelphia Semiconductor Index, which is referred to as the SOX. Between September 30, 2016 (following Versum’s spin-off) and January 25, 2019, the correlation between the stock prices of Versum and Entegris and the SOX was 87% and 96%, respectively. Given that both the Versum and Entegris stock prices were affected by the announcement of the Entegris merger, the initial Parent proposal and other events after January 25, 2019, Lazard adjusted the stock prices of Versum and Entegris as of January 25, 2019 based on the return in the Philadelphia Semiconductor Index ETF, which is referred to as the SOXX, from January 25, 2019 to April 8, 2019 in order to reflect market movement in the semiconductor sector. The SOXX had a nearly 100% correlation with the SOX over the same time period (September 30, 2016 through January 25, 2019) and was used as a proxy for the SOX in order to calculate returns based on the 10-trading day volume-weighted average price and the 20-trading day volume weighted average price. Financial data of the comparable companies were based on publicly available information and calendarized when necessary.

Based on the above analysis and Lazard’s professional judgment, Lazard selected ranges of multiples to estimated calendar year 2019 management-adjusted EBITDA for Versum included in the projections provided by Versum management and approved for Lazard’s use by Versum management. Lazard applied a selected range of multiples of 9.0x to 11.0x to the estimated calendar year 2019 management-adjusted EBITDA of Versum to calculate an enterprise value range for Versum based on the EV / EBITDA multiples implied by the adjusted 10-trading day volume-weighted average prices and the adjusted 20-trading day volume-weighted average prices for Versum and Entegris, then calculated an equity value range using an estimated net debt position and an estimated noncontrolling interest based on Versum’s estimated March 31, 2019 balance sheet provided by Versum management and approved for Lazard’s use by Versum management. The results of the foregoing analysis indicated the following implied per share equity value reference range for Versum, as compared to the consideration to be received in the merger:

P / E Analysis

Lazard reviewed P / E multiples of Versum and Entegris as of January 25, 2019 (the last trading day prior to the announcement of the Entegris merger) based on (1) trading prices on January 25, 2019, (2) 10-trading day

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volume-weighted average prices as of January 25, 2019 and (3) 20-trading day volume-weighted average prices as of January 25, 2019. As noted above, Lazard observed a high correlation between the stock prices of Versum and Entegris and SOX. Between September 30, 2016 (following Versum’s spin-off) and January 25, 2019, the correlation between the stock prices of Versum and Entegris and the SOX was 87% and 96%, respectively. Given that both the Versum and Entegris stock prices were affected by the announcement of the Entegris merger, the initial Parent proposal and other events after January 25, 2019, Lazard adjusted the stock prices of Versum and Entegris as of January 25, 2019 based on the return in SOXX from January 25, 2019 to April 8, 2019 in order to reflect market movement in the semiconductor sector. The SOXX had a nearly 100% correlation with the SOX over the same time period (September 30, 2016 through January 25, 2019) and was used as a proxy for the SOX in order to calculate returns based on the 10-trading day volume-weighted average price and the 20-trading day volume weighted average price. Financial data of the comparable companies were based on publicly available information and calendarized when necessary.

Based on the above analysis and Lazard’s professional judgment, Lazard selected ranges of multiples to estimated calendar year 2019 management-adjusted EPS for Versum included in the projections provided by Versum management and approved for Lazard’s use by Versum management. Lazard applied a selected range of multiples of 14.0x to 17.0x to the estimated calendar year 2019 management-adjusted EPS of Versum based on the P / E multiples implied by the adjusted 10-trading day volume-weighted average prices and the adjusted 20-trading day volume-weighted average prices for Versum and Entegris. The results of the foregoing analysis indicated the following implied per share equity value reference range for Versum, as compared to the consideration to be received in the merger:

Precedent Transactions Valuation Analysis

Lazard reviewed and analyzed, to the extent publicly available, financial information for selected precedent transactions in the chemical industry that Lazard believed, based on its experience, to be relevant for purposes of this analysis, which are collectively referred to as the Lazard precedent transactions. Although none of the Lazard precedent transactions or the companies party to such transactions is directly comparable to the merger or to Versum, the Lazard precedent transactions were chosen because certain aspects of the transactions, for purposes of this analysis and based on the professional judgment and experience of Lazard, may be considered similar to the merger. The analyses necessarily involve complex considerations and judgments concerning differences in financial and operational characteristics of the companies involved and other factors that could affect the transactions differently than they would affect the merger. The Lazard precedent transactions reviewed were:

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For each of the Lazard precedent transactions, Lazard calculated the transaction value as a multiple of the target’s last twelve months (or LTM) EBITDA as of the time of the announcement of the transaction. The overall low to high LTM EBITDA multiples observed for the Lazard precedent transactions were 9.9x to 18.6x. Based on its professional judgment and experience, and taking into consideration the observed multiples for the Lazard precedent transactions, Lazard then applied a selected range of multiples of 13.0x to 15.5x EV / LTM EBITDA to Versum’s estimated LTM March 31, 2019 management-adjusted EBITDA to derive an implied enterprise value range for Versum. The LTM March 31, 2019 management-adjusted EBITDA of Versum was provided by Versum management and approved for Lazard’s use by Versum management. Lazard then calculated an equity value range using an estimated net debt position and an estimated noncontrolling interest based on Versum’s estimated March 31, 2019 balance sheet provided by Versum management and approved for Lazard’s use by Versum management. Financial data of the Lazard precedent transactions were based on public filings and other information. Financial data of Versum was based on the projections provided by Versum management and approved for Lazard’s use by Versum management.

This precedent transactions valuation analysis indicated the following implied per share equity value reference range for Versum, as compared to the consideration to be received in the merger:

Discounted Cash Flow Analysis

Lazard performed a discounted cash flow analysis of Versum, which is an analysis designed to estimate an implied value of a company by calculating the present value of the estimated future unlevered, after-tax free cash flows of that company over the projection period and the terminal value of that company at the end of the projection period. Lazard performed a discounted cash flow analysis of Versum by calculating the estimated present value (as of March 31, 2019) of the unlevered, after-tax free cash flows that Versum was forecasted to generate through fiscal year 2023 based on the projections provided by Versum management and extrapolations based on discussions with, and guidance from, Versum management and approved for Lazard’s use by Versum management, which were calculated by taking net operating profit after tax and adding depreciation and amortization and pension expense, adjusting for the change in net working capital and subtracting capital expenditures. Lazard also calculated estimated terminal values for Versum by applying a perpetual growth rate of 1.5% to 2.5%, derived using publicly available data and Lazard’s professional judgment. Lazard then discounted to present value (as of March 31, 2019) the unlevered, after-tax free cash flows and estimated terminal values using discount rates ranging from 9.5% to 10.5%, derived (1) using market data as of January 25, 2019 (the last trading day prior to the announcement of the Entegris merger) and (2) from an analysis of the weighted average cost of capital of Versum, Entegris and Cabot Microelectronics, which Lazard performed utilizing the capital asset pricing model with inputs that Lazard determined were relevant based on publicly available data and Lazard’s professional judgment. This analysis indicated an implied enterprise value range for Versum, from which Lazard then calculated an equity value range using an estimated net debt position and an estimated noncontrolling interest based on Versum’s estimated March 31, 2019 balance sheet provided by Versum management and approved for Lazard’s use by Versum management.

This discounted cash flow analysis indicated the following implied per share equity value reference range for Versum, as compared to the consideration to be received in the merger:

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Other Analyses

The analyses and data described below were presented to the Versum board of directors for informational and reference purposes only and did not provide a basis for the rendering of Lazard’s opinion.

Present Value of Future Share Price

Overview

Lazard performed an illustrative analysis of the implied present value of Versum’s future value per Versum common stock. This analysis is designed to provide an indication of the present value of a theoretical future value of a company’s equity as a function of such company’s (1) estimated EBITDA and its assumed EV / EBITDA multiple and (2) estimated earnings per share and its assumed P / E multiple. For this analysis, Lazard utilized projected net debt and noncontrolling interest and included the value of cumulative dividends received, based on projections provided by Versum management and extrapolations based on discussions with, and guidance from, Versum management and approved for Lazard’s use by Versum management.

EV / EBITDA Analysis

To calculate the range of the present value of future share prices for Versum, Lazard used the projections provided by Versum management and extrapolations based on discussions with, and guidance from, Versum management and approved for Lazard’s use by Versum management. Lazard applied a range of illustrative next twelve months (or NTM) EV / EBITDA multiples of 9.0x to 11.0x to forward EBITDA from fiscal year 2019 to fiscal year 2022 to calculate a future enterprise value range for Versum, then calculated an equity value range using an estimated net debt position and an estimated noncontrolling interest based on the projected balance sheet and included the value of cumulative dividends received. Lazard then discounted such figures back to March 31, 2019 using a discount rate of 12.2%, which reflects an estimate of Versum’s cost of equity that was calculated by Lazard based on (1) market data as of January 25, 2019 (the last trading day prior to the announcement of the Entegris merger) and (2) the capital asset pricing model with inputs that Lazard determined were relevant based on publicly available data and Lazard’s professional judgment. This analysis indicated the following implied per share equity value reference range for Versum:

P / E Analysis

To calculate the range of the present value of future share prices for Versum, Lazard used the projections provided by Versum management and extrapolations based on discussions with, and guidance from, Versum management and approved for Lazard’s use by Versum management. Lazard applied a range of illustrative NTM P / E multiples of 14.0x to 17.0x to forward EPS from fiscal year 2019 to fiscal year 2022 and included the value of cumulative dividends received. Lazard then discounted such figures back to March 31, 2019 using a discount rate of 12.2%, which reflects an estimate of Versum’s cost of equity that was calculated by Lazard based on (1) market data as of January 25, 2019 (the last trading day prior to the announcement of the Entegris merger) and (2) the capital asset pricing model with inputs that Lazard determined were relevant based on publicly available data and Lazard’s professional judgment. This analysis indicated the following implied per share equity value reference range for Versum:

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Miscellaneous

In connection with Lazard’s services as financial advisor, Versum agreed to pay Lazard an aggregate fee for such services of $18 million, which is contingent upon the consummation of the merger. In the event that Versum or its affiliates is paid any break-up, termination, topping or similar fee in connection with a potential transaction, Versum has agreed to pay Lazard a fee equal to 20% of such amount net of Versum’s fees and expenses in connection with such potential transaction, provided that the amount payable shall (1) not exceed $15 million and (2) be credited (without duplication) against any amount that may be subsequently paid pursuant to the immediately preceding sentence. Versum also agreed to reimburse Lazard for certain reasonable expenses incurred in connection with Lazard’s engagement and to indemnify Lazard and certain related persons under certain circumstances against certain liabilities that may arise from or relate to Lazard’s engagement.

The financial advisory business of Lazard has in the past provided certain investment banking services to Versum, for which it has received compensation during the past two years in the amount of approximately $250,000 with respect to corporate preparedness matters and $2.0 million with respect to the Entegris merger. In addition, the financial advisory business of Lazard has in the past provided certain investment banking services to Parent, for which it has received compensation during the past two years in the aggregate amount of approximately $8.2 million, including with respect to having advised Parent with respect to certain assets, including a transaction with Intrexon Corporation in 2018 and an alliance with GlaxoSmithKline plc in 2019.

Lazard, as part of its investment banking business, is continually engaged in valuations of businesses and securities in connection with mergers and acquisitions, negotiated underwritings, secondary distributions of listed and unlisted securities, private placements, leveraged buyouts and valuations for other purposes. In addition, in the ordinary course, Lazard and its affiliates and employees may trade securities of Versum, Parent and certain of their respective affiliates for their own accounts and for the accounts of their customers, may at any time hold a long or short position in such securities, and may also trade and hold securities on behalf of Versum, Parent and certain of their respective affiliates. The issuance of Lazard’s opinion was approved by the opinion committee of Lazard.

Lazard prepared these analyses solely for purposes of, and the analyses were delivered to the Versum board of directors in connection with, the provision of its opinion to the Versum board of directors as to the fairness from a financial point of view of the consideration to the Versum stockholders (other than holders of Versum excluded shares). Lazard did not recommend any specific consideration to the Versum board of directors or that any given amount of consideration constituted the only appropriate consideration for the merger. Lazard’s opinion and analyses were only one of many factors taken into consideration by the Versum board of directors in its evaluation of the merger. Consequently, the analyses described above should not be viewed as determinative of the views of the Versum board of directors or Versum’s management with respect to the consideration provided for in the merger or as to whether the Versum board of directors would have been willing to determine that a different consideration was fair.

Lazard is an internationally recognized investment banking firm providing a full range of financial advisory and other services. Lazard was selected to act as investment banker to Versum because of its qualifications, expertise and reputation in investment banking and mergers and acquisitions generally and in the chemicals industry specifically, as well as its familiarity with the business of Versum.

Opinion of Citigroup Global Markets, Inc.

Versum retained Citi as a financial advisor in connection with the merger. In connection with Citi’s engagement, Versum requested that Citi evaluate the fairness, from a financial point of view, of the merger consideration to be received in the merger by holders of shares of Versum common stock (other than treasury shares and Parent owned shares) pursuant to the terms and subject to the conditions set forth in the merger agreement. On April 11, 2019, at a meeting of the Versum board of directors held to evaluate the proposed

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merger and at which the merger agreement was approved, Citi delivered to the Versum board of directors an oral opinion, confirmed by delivery of a written opinion dated April 11, 2019, to the effect that, as of that date and based on and subject to various assumptions made, procedures followed, matters considered and limitations and qualifications on the review undertaken by Citi as set forth in its written opinion, the merger consideration to be received in the merger by holders of Versum common stock (other than treasury shares and Parent owned shares) pursuant to the merger agreement was fair, from a financial point of view, to such holders.

The full text of Citi’s written opinion, dated April 11, 2019, to the Versum board of directors, which sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations and qualifications on the review undertaken by Citi in rendering its opinion, is attached to this proxy statement as Annex C and is incorporated herein by reference in its entirety. The summary of Citi’s opinion set forth below is qualified in its entirety by reference to the full text of Citi’s opinion. Citi’s opinion was provided to the Versum board of directors (in its capacity as such) in connection with its evaluation of the merger and was limited to the fairness, from a financial point of view, as of the date of the opinion, to the holders of Versum common stock (other than treasury shares and Parent owned shares) of the merger consideration. Citi’s opinion did not address any other aspects or implications of the merger or the merger agreement. Citi’s opinion is not intended to be and does not constitute a recommendation to any stockholder as to how such stockholder should vote or act on any matters relating to the proposed merger or otherwise.

In arriving at its opinion, Citi:

The issuance of Citi’s opinion was authorized by Citi’s fairness opinion committee.

In rendering its opinion, Citi assumed and relied, without independent verification, upon the accuracy and completeness of all financial and other information and data publicly available or provided to or otherwise reviewed by or discussed with Citi and upon the assurances of the management of Versum that they were not aware of any relevant information that was omitted or that remained undisclosed to Citi. With respect to the financial forecasts and other information and data relating to Versum provided to or otherwise reviewed by or discussed with Citi, Citi was advised by the management of Versum and Citi assumed, with Versum’s consent, that such forecasts and other information and data were reasonably prepared on bases reflecting the best currently

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available estimates and judgments of the management of Versum as to, and were a reasonable basis upon which to evaluate, the future financial performance of Versum and the other matters covered thereby. Citi expressed no view or opinion as to any financial forecasts and other information or data (or underlying assumptions on which any such financial forecasts and other information or data were based) provided to or otherwise reviewed by or discussed with Citi.

Citi assumed, with Versum’s consent, that the merger would be consummated in accordance with its terms, without waiver, modification or amendment of any material term, condition or agreement, and that, in the course of obtaining the necessary regulatory or third party approvals, consents and releases for the merger, no delay, limitation, restriction or condition would be imposed that would have an adverse effect on Versum or the merger that would be in any way meaningful to Citi’s analysis. Representatives of Versum advised Citi, and Citi further assumed, that the final terms of the merger agreement would not vary materially from those set forth in the execution version reviewed by Citi. Citi did not make and was not provided with an independent evaluation or appraisal of the assets or liabilities (contingent or otherwise) of Versum and nor did Citi make any physical inspection of the properties or assets of Versum. Citi expressed no view or opinion as to any pending or potential litigation, claims or governmental, regulatory or other proceedings or investigations. Citi was not requested to, and Citi did not, solicit third party indications of interest in the possible acquisition of all or a part of Versum, nor was Citi requested to consider, and its opinion did not address, the underlying business decision of Versum to effect the merger, the relative merits of the merger as compared to any alternative business strategies that might exist for Versum or the effect of any other transaction in which Versum might engage. Citi did not express any view as to, and its opinion did not address, the prices at which Versum common stock or any other securities would trade or otherwise be transferable at any time, including following the announcement of the merger. Citi expressed no view as to, and its opinion did not address, the fairness (financial or otherwise) of the amount or nature or any other aspect of any compensation to any officers, directors or employees of any parties to the merger, or any class of such persons, relative to the merger consideration.

Citi’s opinion was necessarily based upon information available to Citi, and financial, stock market and other conditions and circumstances existing, as of the date of its opinion. Although subsequent developments may affect Citi’s opinion, Citi has no obligation to update, revise or reaffirm its opinion. Citi’s opinion addressed only the fairness, from a financial point of view and as of the opinion’s date, of the per share of Versum common stock merger consideration (to the extent expressly specified in such opinion), without regard to individual circumstances of holders of Versum common stock that may distinguish such holders or the securities of Versum held by such holders.

In preparing its opinion, Citi performed a variety of financial and comparative analyses, including those described below. The summary of the analyses below is not a complete description of Citi’s opinion or the analyses underlying, and factors considered in connection with, Citi’s opinion. The preparation of a financial opinion is a complex analytical process involving various determinations as to the most appropriate and relevant methods of financial analysis and the application of those methods to the particular circumstances and, therefore, a financial opinion is not readily susceptible to partial analysis or summary description. Citi arrived at its opinion based on the results of all analyses undertaken by it and factors assessed as a whole, and it did not draw, in isolation, conclusions from or with regard to any one factor or method of analysis for purposes of its opinion. Accordingly, Citi believes that the analyses must be considered as a whole and that selecting portions of such analyses and factors or focusing on information presented in tabular format, without considering all analyses and factors or the narrative description of the analyses, could create a misleading or incomplete view of the processes underlying such analyses and Citi’s opinion.

In its analyses, Citi considered industry performance, general business, economic, market and financial conditions and other matters existing as of the date of its opinion, many of which are beyond the control of Versum. No company, business or transaction used in Citi’s analyses as a comparison is identical or directly comparable to Versum or the merger. An evaluation of these analyses is not entirely mathematical; rather the analyses involve complex considerations and judgments concerning financial and operating characteristics and

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other factors that could affect the acquisition, public trading or other values of the companies, businesses or transactions reviewed or the results of any particular analysis.

The estimates contained in Citi’s analyses and the valuation ranges resulting from any particular analysis are not necessarily indicative of actual values or predictive of future results or values, which may be significantly more or less favorable than those suggested by such analyses. In addition, analyses relating to the value of businesses or securities do not purport to be appraisals or to reflect the prices at which businesses or securities actually may be sold or acquired. Accordingly, the estimates used in, and the results derived from, Citi’s analyses are inherently subject to substantial uncertainty.

Citi was not requested to, and it did not, recommend or determine the specific consideration payable in the merger. The type and amount of consideration payable in the merger was determined through negotiations between Versum and Parent and Versum’s decision to enter into the merger agreement was solely that of the Versum board of directors. Citi’s opinion was only one of many factors considered by the Versum board of directors in its evaluation of the merger and should not be viewed as determinative of the views of the Versum board of directors or the management of Versum with respect to the merger, merger consideration or any other aspect of the transactions contemplated by the merger agreement.

Financial Analyses

The following is a summary of the material financial analyses prepared and reviewed with the Versum board of directors in connection with Citi’s opinion, dated April 11, 2019, to the Versum board of directors. The summary set forth below does not purport to be a complete description of the financial analyses performed by, and underlying the opinion of, Citi, nor does the order of the financial analyses described represent the relative importance or weight given to those financial analyses by Citi. Certain financial analyses summarized below include information presented in tabular format. In order to fully understand the financial analyses, the tables must be read together with the text of each summary as the tables alone do not constitute a complete description of the financial analyses. Considering the data in the tables below without considering the full narrative description of the financial analyses, including the methodologies and assumptions underlying the financial analyses, could create a misleading or incomplete view of such financial analyses. Future results may be different from those described and such differences may be material. For purposes of the financial analyses described below, the term “adjusted EBITDA” generally means earnings before interest, taxes, depreciation and amortization, which is referred to as EBITDA, adjusted to include stock-based compensation expense, and exclude onetime, nonrecurring and non-cash items. Financial data utilized for Versum in the financial analyses described below, to the extent based on internal financial forecasts and estimates of management, were based on certain financial forecasts and other information and data relating to Versum provided to or discussed with Citi by the management of Versum and as further described in the section entitled “— Versum Unaudited Financial Projections ” beginning on page 61. Citi performed its financial analyses using projected financial and operating results for Versum for the calendar year 2019 through calendar year 2023 based on the Versum Projections, which were presented on a fiscal year basis ending September 30 of each year, and as defined and further described in “— Versum Unaudited Financial Projections ” beginning on page 61. Citi calculated calendar year financial data for each year by combining 75% of the applicable item in the Versum Projections from the corresponding fiscal year and 25% of the same item in the Versum Projections from the next succeeding fiscal year. The financial data for the last three months of calendar year 2023 was extrapolated by Citi using the same estimates, judgments, assumptions and limitations used by the management of Versum in calculating the Versum Projections’ fiscal year 2023 financial data. Approximate implied equity value per share reference ranges reflected in the summaries of the financial analyses described below were rounded to the nearest $0.05.

Comparable Companies Analysis

Citi performed a comparable companies analysis, which is an analysis designed to estimate an implied value of a company through an analysis of the public valuation of similar publicly traded companies. Citi reviewed

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financial and stock market information of Versum and the comparable publicly traded companies described below, which are collectively referred to as the comparable companies. No publicly traded company is identical to Versum, but these companies were selected because, among other reasons, they possessed certain financial, operational or business characteristics that, in Citi’s view, were sufficiently comparable to those of Versum or otherwise relevant for purposes of comparison.

Citi reviewed, among other information, firm values of the comparable companies, calculated as fully diluted equity values (based on closing stock prices of the comparable companies on January 25, 2019, the last trading date prior to the announcement of the Entegris merger) plus debt and non-controlling interests (as applicable), as a multiple of calendar year 2019 estimated EBITDA. The observed multiples of firm value to calendar year 2019 estimated EBITDA for Versum and the comparable companies ranged from a low of 8.4x to a high of 10.3x, with such multiple for Versum being 8.4x, for Entegris being 10.2x and for Cabot Microelectronics Corporation being 10.3x. Based on its professional judgment and experience, and taking into consideration the observed multiples for the comparable companies, Citi then applied a selected range of multiples of firm value to calendar year 2019 estimated EBITDA of 8.4x to 11.0x, derived from the comparable companies, to calendar year estimated 2019 adjusted EBITDA of Versum to calculate an implied equity value reference range for Versum for fully diluted shares outstanding. Citigroup selected this range based on Versum’s multiple of firm value to calendar year 2019 estimated EBITDA as of January 25, 2019, the trading date prior to the announcement of the Entegris merger, and Versum’s median multiple to next 12 months EBITDA since September 19, 2016, the first trading date of Versum common stock. Financial data of the comparable companies were based on publicly available Wall Street research analysts’ estimates and other publicly available information and calendarized when necessary. The calendar year 2019 estimated adjusted EBITDA of Versum of $503 million, derived from the fiscal year 2019 and fiscal year 2020 estimated adjusted EBITDA of Versum provided by the management of Versum, was used by Citi at the direction of, the management of Versum. Financial data of Versum was based on public filings and Versum’s forecasts.

This analysis indicated an implied equity value reference range for Versum of approximately $3.6 billion to $4.9 billion, from which, after taking into account, an assumed net debt position of approximately $579 million and, an assumed non-controlling interest of approximately $36 million, in each case, based on Versum’s December 31, 2018 balance sheet, the following approximate equity value per share of Versum common stock reference range for Versum was derived, as compared to the merger consideration to be received in the merger.

Precedent Transactions Analysis

Citi performed a precedent transactions analysis, which is an analysis designed to estimate an implied value of a company through an analysis of the multiples paid in acquisitions of similar companies and businesses. Citi reviewed, to the extent publicly available, financial information for selected precedent transactions in the specialty chemicals industry announced between December 2013 and August 2018, which are collectively referred to as the Citi precedent transactions.

The Citi precedent transactions were chosen because they involved companies with financial, operational or business characteristics that, in Citi’s view, made them sufficiently comparable to Versum and/or the transactions contemplated by the merger agreement or otherwise relevant for purposes of comparison. For each of the Citi

precedent transactions, Citi calculated the firm value as a multiple of the target’s last twelve months (or LTM)

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EBITDA as of the time of the announcement of the transaction. The observed multiples for the Citi precedent transactions are set forth in the table below and ranged from 9.9x to 18.6x (with a median of 13.0x).

Based on its professional judgment and experience, and taking into consideration the observed multiples for the Citi precedent transactions, Citi then applied a selected range of calendar year 2018 EBITDA multiples of 13.0x to 15.3x derived from the median firm value / LTM multiple of the Citi precedent transactions and the firm value / LTM multiple of the BASF SE and Chemetall surface treatment business transaction, respectively, to derive an implied equity value per share of Versum common stock. Financial data of the Citi precedent transactions were based on public filings and other information. Financial data of Versum were based on financial information provided by, and used by Citi at the direction of, the management of Versum.

Citi applied the 13.0x to 15.3x range of firm value / LTM EBITDA multiples to Versum’s calendar year 2018 adjusted EBITDA. The calendar year 2018 adjusted EBITDA of Versum of $453 million, derived from fiscal year 2018 and 2019 adjusted EBITDA of Versum from publicly available information and used by Citi at the direction of, the management of Versum, indicating an implied firm value reference range for Versum of approximately $5.9 billion to $6.9 billion, from which, after taking into account, an assumed net debt position of approximately $579 million and, an assumed non-controlling interest of approximately $36 million, in each case, based on Versum’s December 31, 2018 balance sheet, the following approximate implied equity value per share reference range for Versum was derived, as compared to the merger consideration to be received in the merger:

Discounted Cash Flow Analysis

Citi performed a discounted cash flow analysis of Versum, which is an analysis designed to estimate an implied value of a company by calculating the present value of the estimated future unlevered after-tax free cash flows of that company over the projection period and the terminal value of that company at the end of the projection period. Citi performed this analysis using a mid-year discounting convention, as described below.

Citi performed a discounted cash flow analysis of Versum in which Citi calculated the estimated present value (as of December 31, 2018) of the standalone unlevered after-tax free cash flows that Versum was

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forecasted to generate during calendar year 2019 through calendar year 2023, derived from the fiscal year 2019 through fiscal year 2023 projections provided by the management of Versum and as further described in “— Versum Unaudited Financial Projections ” beginning on page 61, and used by Citi at the direction of the management of Versum. For purposes of the discounted cash flow analysis, Citi used Versum’s unlevered after-tax free cash flows, which were computed by taking net operating profit after tax, and adding depreciation and amortization and pension expense, adjusting for net working capital, and subtracting capital expenditures and pension contributions. Based on its professional judgment and experience, Citi calculated terminal values for Versum by applying a selected range of perpetuity growth rates of 1.5% to 2.5% to the standalone unlevered after-tax free cash flows of Versum for the calendar year ending December 31, 2023. Citi then discounted to present value (as of December 31, 2018) the unlevered after-tax free cash flows and implied estimated terminal value using discount rates ranging from 8.9% to 10.3%, derived from a calculation of the weighted average cost of capital of Versum, which Citi performed utilizing the capital asset pricing model with inputs that Citi determined were relevant based on publicly available data and Citi’s professional judgment. This analysis indicated an implied firm value reference range for Versum of approximately $4.8 billion to $6.4 billion, from which, after taking into account, an assumed net debt position of approximately $579 million and, an assumed non-controlling interest of approximately $36 million, in each case, based on Versum’s December 31, 2018 balance sheet, the following approximate implied equity value per share of Versum common stock reference range for Versum was derived, as compared to the merger consideration to be received in the merger:

Versum and/or certain of its affiliates, including corporate portfolio management services. For the services described above for Versum, Citi and its affiliates received during the two-year period prior to the date of Citi’s opinion aggregate fees of approximately $0.8 million.

As the Versum board of directors also was aware, Citi and its affiliates in the past have provided, currently are providing and in the future may provide certain investment banking, commercial banking and other financial services to Parent and its affiliates unrelated to the proposed merger, for which services Citi and its affiliates have received and expect to receive compensation, including, during the two-year period prior to the date of Citi’s opinion, (i) having acted or acting as a lender to Parent and/or certain of its affiliates and (ii) having provided or providing services to Parent and/or certain of its affiliates, including global foreign exchange management and global credit market services, cash management and treasury services, corporate portfolio management services and other corporate and institutional client group services. For the services described above for Parent, Citi and its affiliates did not receive any fees during the two-year period prior to the date of Citi’s opinion. In the ordinary course of Citi’s business, Citi and its affiliates may actively trade or hold the securities of Versum and Parent for its own account or for the account of its customers and, accordingly, may at any time hold a long or short position in such securities.

Versum selected Citi as a financial advisor in connection with the merger based on Citi’s reputation, experience and familiarity with Versum and its business. Citi is an internationally recognized investment banking firm that regularly engages in the valuation of businesses and their securities in connection with mergers and acquisitions and other purposes.

Versum Unaudited Financial Projections

Versum has historically prepared and provided public guidance as to its projected financial and operational results for its then-current fiscal year in its press releases announcing its financial results for the then-current quarter or year, as applicable. Other than the financial guidance described above, Versum does not as a matter of course make other public projections as to future sales, earnings, or other results, and forecasts for extended periods of time are of particular concern to Versum due to the unpredictability of the underlying assumptions and estimates. However, in connection with the discussions regarding the proposed merger, Versum management prepared certain unaudited prospective financial information for fiscal years 2019 through 2021 for its board of directors, Lazard and Citi, and Parent, Guggenheim and Goldman Sachs, and Lazard prepared, based on discussions with and under the guidance of Versum management, extrapolations thereto, which were not made available to Parent, Guggenheim and Goldman Sachs (except to the extent publicly disclosed in the joint proxy statement/prospectus on Schedule 14A filed with the SEC by Versum on March 20, 2019), for fiscal years 2022 through 2023, which are referred to collectively as the Versum Projections. The Versum Projections were prepared treating Versum on a stand-alone basis, without giving effect to the Entegris merger or the Parent merger including the impact of negotiating or executing the Entegris merger or the Parent merger, the expenses that may be incurred in connection with consummating the Parent merger, including the Entegris termination fee, the potential synergies that may be achieved as a result of the Entegris merger or the Parent merger, the effect of any business or strategic decision or action that has been or will be taken as a result of the merger agreement with Entegris or Parent having been executed, or the effect of any business or strategic decisions or actions which would likely have been taken if the merger agreement with Entegris or Parent had not been executed but which were instead altered, accelerated, postponed or not taken in anticipation of the Entegris merger or the Parent merger.

The accompanying Versum Projections were not prepared with a view toward public disclosure or with a view toward compliance with the published guidelines established by the SEC or the American Institute of Certified Public Accountants for preparation or presentation of prospective financial information, or generally accepted accounting principles, which is referred to as GAAP, but, in the view of Versum’s management, were prepared on a reasonable basis, reflected the best available estimates and judgments at the time of preparation, and presented as of the time of preparation, to the best of management’s knowledge and belief, the expected

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course of action and the expected future financial performance of Versum on a stand-alone basis as described above and subject to the assumptions and limitations described in this section. However, this information is not fact and should not be relied upon as being necessarily indicative of future results, and readers of this proxy statement are cautioned not to place undue reliance on the Versum Projections. Although Versum’s management believes there is a reasonable basis for the Versum Projections, Versum cautions stockholders that future results could be materially different from the Versum Projections. This summary of the Versum Projections is not being included in this proxy statement to influence your decision whether to vote for the merger agreement proposal, but because these Versum Projections were shared between Versum and Parent and provided to Versum’s and Parent’s respective financial advisors and boards of directors for purposes of considering and evaluating the merger and the merger agreement. Versum’s independent registered public accounting firm has not audited, reviewed, examined, compiled nor applied agreed-upon procedures with respect to the Versum Projections and, accordingly, does not express an opinion or any other form of assurance with respect thereto.

The Versum Projections are subject to estimates and assumptions in many respects and, as a result, subject to interpretation. While presented with numerical specificity, the Versum Projections are based upon a variety of estimates and assumptions that are inherently uncertain, though considered reasonable by Versum’s management as of the date of their preparation. These estimates and assumptions may prove to be inaccurate for any number of reasons, including general economic conditions, competition, and the risks discussed in this proxy statement under the sections entitled “ Cautionary Statement Regarding Forward-Looking Statements ” beginning on page 25. See also “ Where You Can Find More Information ” beginning on page 122. The Versum Projections also reflect assumptions as to certain business decisions that are subject to change. Because the Versum Projections were developed for Versum on a stand-alone basis without giving effect to the Entegris merger or the Parent merger, they do not reflect any divestitures or other restrictions that may be imposed in connection with the receipt of any necessary governmental or regulatory approvals, any synergies that may be realized as a result of the merger or any changes to Versum’s operations or strategy that may be implemented after completion of the merger. There can be no assurance that the Versum Projections will be realized, and actual results may differ materially from those shown. Generally, the further out the period to which the Versum Projections relate, the less predictable and more unreliable the information becomes.

The Versum Projections contain certain non-GAAP financial measures that Versum believes are helpful in understanding its past financial performance and future results. Versum management regularly uses a variety of financial measures that are not prepared in accordance with GAAP, including Adjusted EBITDA (defined as net income excluding certain items which Versum does not believe to be indicative of underlying business trends, including interest expense, the write-off of financing costs, non-service components of net periodic pension cost, income tax provision, depreciation and amortization expense, non-controlling interests, and business separation, restructuring and cost reduction actions) for forecasting, budgeting and measuring operating performance. The non-GAAP financial measures are not meant to be considered in isolation or as a substitute for comparable GAAP measures. While Versum believes that these non-GAAP financial measures provide meaningful information to help investors understand Versum’s operating results and to analyze Versum’s financial and business trends on a period-to-period basis, there are limitations associated with the use of these non-GAAP financial measures. These non-GAAP financial measures are not prepared in accordance with GAAP, are not reported by all of Versum’s competitors and may not be directly comparable to similarly titled measures of Versum’s competitors due to potential differences in the exact method of calculation.

Versum has not provided reconciliations of the non-GAAP financial measures included in these projections to the comparable GAAP measure due to no reasonably accessible or reliable comparable GAAP measures for these measures and the inherent difficulty in forecasting and quantifying the measures that are necessary for such reconciliation.

None of Versum or any of its affiliates, advisors, officers, directors or other representatives can provide any assurance that actual results will not differ from the Versum Projections, and none of them undertakes any obligation to update, or otherwise revise or reconcile, the Versum Projections to reflect circumstances existing

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after the date the Versum Projections were generated or to reflect the occurrence of future events even in the event that any or all of the assumptions underlying the Versum Projections, as applicable, are shown to be in error. Except as required by applicable securities laws, Versum does not intend to make publicly available any update or other revision to the Versum Projections, even in the event that any or all assumptions are shown to be in error. Versum has made publicly available its actual results of operations for the year ended September 30, 2018 on Versum’s Annual Report on Form 10-K filed with the SEC on November 21, 2018 and for the quarterly period ended December 31, 2018 on Versum’s Quarterly Report on Form 10-Q filed with the SEC on February 7, 2019. None of Versum or its affiliates, advisors, officers, directors or other representatives has made or makes any representation to any Versum stockholder or other person regarding Versum’s ultimate performance compared to the information contained in the Versum Projections or that forecasted results will be achieved. Versum has made no representation to Parent, in the merger agreement or otherwise, concerning the Versum Projections.

Closing and Effective Time of the Merger

The closing of the merger will take place on the fourth business day following the day on which the last to be satisfied or (to the extent permissible) waived of the conditions for completion of the merger set forth in the merger agreement (other than those conditions that by their nature must be satisfied or waived at the closing (so long as such conditions are reasonably capable of being satisfied), but subject to the satisfaction or waiver of those conditions) is satisfied or (to the extent permissible) waived in accordance with the merger agreement or on such other date as Versum and Parent may mutually agree in writing. Subject to the satisfaction or waiver of the conditions to the closing described in the section entitled “ The Merger Agreement—Conditions to the Completion of the Merger ” beginning on page 105, including the adoption of the merger agreement by Versum stockholders at the special meeting, it is anticipated that the merger will close in the second half of 2019. However, Versum cannot predict the actual date on which the merger will be completed, or if the completion will occur at all, because completion is subject to conditions and factors outside of its and Parent’s control. It is possible that factors outside the control of both companies could result in the merger being completed at a different time, or not at all.

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As soon as practicable following, and on the date of, the closing, Parent and Versum will cause a certificate of merger relating to the merger, which is referred to as the certificate of merger, to be executed, acknowledged and filed with the Secretary of State of the State of Delaware as provided in Section 251 of the DGCL. The merger will become effective at the time when the certificate of merger has been duly filed with and accepted by the Secretary of State of the State of Delaware or at such later date and time as may be agreed by Parent and Versum in writing and specified in the certificate of merger.

Interests of Versum’s Directors and Executive Officers in the Merger

In considering the recommendations of the Versum board of directors, Versum stockholders should be aware that Versum’s directors and executive officers have interests in the merger, including financial interests, that may be different from, or in addition to, the interests of the other Versum stockholders generally. These interests are described in more detail below, and with respect to the named executive officers of Versum, are quantified in the tables below in the section entitled “ —Quantification of Payments and Benefits to Versum ’ s Named Executive Officers ” beginning on page 68. The Versum board of directors was aware of and considered these interests, among other matters, in reaching its decisions to adopt the merger agreement and approve the transactions contemplated thereby and to recommend the adoption of the merger agreement to Versum stockholders. See the sections entitled “ — Background of the Merger ” and “ —Recommendation of the Versum Board of Directors; Versum ’ s Reasons for the Merger ” beginning on pages 34 and 42, respectively.

Executive Officers

For purposes of this proxy statement, Versum’s “named executive officers” are (1) Guillermo Novo, President and Chief Executive Officer, (2) George G. Bitto, Executive Vice President and Chief Financial Officer, (3) Michael W. Valente, Senior Vice President, General Counsel and Secretary, (4) Edward C. Shober, Senior Vice President, Materials, and (5) Patrick F. Loughlin. Mr. Loughlin served as Versum’s Senior Vice President, Operations and Supply Chain, through October 31, 2018. For purposes of this disclosure, Versum’s “executive officers” are its named executive officers, together with (a) Dr. John G. Langan, Senior Vice President and Chief Technology Officer and (b) John J. (“Jeff”) White, Senior Vice President, Delivery Systems and Services.

Stock Options, Time-Based Restricted Stock Units, and Performance-Based Restricted Units; Deferred Stock Units

Pursuant to the merger agreement, at the effective time:

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One member of the Versum board of directors, Ambassador Alejandro D. Wolff, has an account balance under the Director DCP. Each DSU award held in Ambassador Wolff’s Director DCP account shall be fully vested and be canceled and converted into the right to receive a cash amount equal to the product of (i) the number of shares of Versum common stock underlying the DSU award held in Ambassador Wolff’s Director DCP account and (ii) the merger consideration, which cash amount will be paid no later than 30 business days following the effective time.

If the closing of the merger has not taken place by November 15, 2019, Versum may make annual grants of equity awards to its employees and its subsidiaries’ employees in the ordinary course of business consistent with past practice in (i) an aggregate dollar amount that is no more than the aggregate dollar amount granted to its employees and its subsidiaries’ employees in connection with Versum’s fiscal year 2019 ordinary course annual equity grants (excluding any special or one-off equity grants made in Versum’s fiscal year 2019) and (ii) individual dollar amounts that are not materially greater than the individual dollar amounts granted to its employees and its subsidiaries’ employees in connection with Versum’s fiscal year 2019 ordinary course annual equity grants (except that the individual dollar amount of any annual equity grant made to an executive officer shall not exceed the individual dollar amount of the fiscal year 2019 ordinary course annual equity grant, excluding any special or one-off grants, made to such executive officer); provided that no such equity awards granted in fiscal year 2020 will contain “double-trigger” vesting protections relating to the transaction contemplated by the merger agreement. Equity awards granted in fiscal year 2020 may be granted in the form of RSU awards or in the same proportion of RSU awards to PSU awards with respect to fiscal year 2019; provided that, at the effective time, any PSU awards granted in fiscal year 2020 will be converted into a deferred cash payment based on target performance.

For an estimated value of the accelerated deferred cash payments corresponding to RSU awards and PSU awards, as described above, that would be payable to Versum’s named executive officers upon a covered

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termination, please see the section entitled “ —Quantification of Payments and Benefits to Versum’s Named Executive Officers ” beginning on page 68 below. As of the date of this proxy statement, no Versum directors hold options, and all options awarded to Versum’s executive officers are fully vested. The estimated value of the accelerated deferred cash payments corresponding to RSU awards and PSU awards, as described above, payable upon a covered termination of Versum’s executive officers who are not named executive officers (including accrued cash dividends and based on the same assumptions used to determine the named executive officers’ acceleration value in the section entitled “ —Quantification of Payments and Benefits to Versum’s Named Executive Officers ” beginning on page 68) is $6,308,130. The estimated value of the accelerated Versum RSU awards payable to Versum’s non-employee directors upon a covered termination is $825,373. The estimated value of the DSU award (based on an assumed share price of $53.00) is $333,445.

Versum Change in Control Severance

Versum’s executive officers are eligible for enhanced severance benefits under their respective employment agreements if they are terminated following a change in control. Mr. Loughlin served as Versum’s Senior Vice President, Operations and Supply Chain, through October 31, 2018 and is not entitled to enhanced or additional severance benefits under his employment agreement as a result of the merger.

If the employment of Messrs. Novo, Bitto, Valente, Shober, White or Langan is terminated without cause or, in the case of Messrs. Novo, Bitto or Valente, by such executive officer for good reason, following a change in control, each of which is referred to as a qualifying termination, the executive officer will be entitled to, in addition to accrued but unpaid base salary and earned but unpaid prior year annual bonus, the following payments and benefits: (i) a lump sum pro rata portion of any annual bonus based upon actual performance for the fiscal year in which the termination of employment occurs; (ii) a lump sum payment equal to the sum of (x) the executive’s monthly base salary at termination and (y) 1/12th of the executive’s average annual bonus paid with respect to the last three full fiscal years prior to the year of termination, with such sum multiplied by 36 for Mr. Novo, 24 for Messrs. Bitto and Valente and 12 for Messrs. Shober, White and Langan; (iii) healthcare benefits under COBRA for 12 months or, if sooner, until the executive’s COBRA eligibility ceases; (iv) $20,000 for Messrs. Novo, Bitto and Valente and $10,000 for Messrs. Shober, White and Langan, for outplacement services; and (v) an amount equal to the matching and the maximum non-elective contributions to the executive officer’s qualified and non-qualified plans that would have been made based on the executive officer’s most recent deferral elections and base salary, respectively, for the 12 months following such termination.

To receive any of the foregoing cash payments or benefits under the executive officer’s employment agreement, the terminated executive officer must sign (and not revoke) a release of claims and continue to comply with covenants of non-competition, non-solicitation of employees, consultants and independent contractors, non-solicitation and non-interference with business relationships (for a period of three years after the date of termination in the case of Mr. Novo, two years in the case of Messrs. Bitto and Valente and one year in the case of Messrs. Shober, Langan and White), confidentiality and nondisparagement.

Under the employment agreements, if an executive officer’s merger-related payments are subject to Section 4999 of the Code, then the executive officer will either receive all such payments and benefits subject to the excise tax or such payments and benefits will be reduced so that the excise tax does not apply, whichever approach yields the best after tax outcome for the executive officer. Versum may, in consultation with Parent, mitigate the impact of the excise tax under Section 4999 of the Code on the executive officers and the lost deduction to Parent under Section 280G of the Code by (i) accelerating payments of earned or reasonably expected to be earned cash incentive compensation that would be payable in 2020 to December 2019, (ii) accelerating the vesting or settlement of Versum equity awards scheduled to vest after December 31, 2019 and prior to the effective time of the merger and (iii) valuing certain non-compete covenants.

For an estimate of the amounts of severance that would be payable to Versum’s named executive officers upon a qualifying termination, please see the section entitled “ —Quantification of Payments and Benefits to

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Versum’s Named Executive Officers ” beginning on page 68 below. The estimated value of the severance benefits that would be payable to the Versum executive officers who are not named executive officers upon a qualifying termination is $1,634,352 in the aggregate, which is based on the same assumptions used to calculate the estimated payments to Versum’s named executive officers in the section entitled “ —Quantification of Payments and Benefits to Versum’s Named Executive Officers ” beginning on page 68 below.

Versum Deferred Compensation Plan

Versum’s executive officers have account balances under the DCP. As soon as administratively feasible following the effective time, but in no event longer than 90 days thereafter, Versum will pay each participant a single lump-sum cash payment of such participant’s accrued account balance. The executive officers’ account balances under the DCP are fully vested, and none of the executive officers are eligible to receive any additional vesting or enhancements under the DCP upon the merger or termination of employment following the merger. These accrued account balances, as of May 6, 2019, are as follows:

Indemnification; Directors’ and Officers’ Insurance

Pursuant to the terms of the merger agreement, certain directors and officers of Versum and its subsidiaries will be entitled to certain ongoing indemnification and coverage under directors’ and officers’ liability and fiduciary liability insurance policies following the merger. Such indemnification and insurance coverage is further described in the section entitled “ The Merger Agreement—Indemnification; Directors’ and Officers’ Insurance ” beginning on page 104.

Other Compensation Matters

In connection with the merger, Versum has established a cash-based retention program for the benefit of Versum’s and its subsidiaries’ employees, including Versum’s executive officers, with the aggregate retention pool not to exceed $18 million, less any amounts granted under the cash-based retention program previously established in connection with the Entegris merger agreement, and subject to certain additional limitations. Such retention bonuses are payable promptly following the six-month anniversary of the effective time, subject to continued employment through such date or, if earlier, promptly following a qualifying termination of employment. In addition, in connection with the merger, Versum amended retention bonuses previously granted to Messrs. Novo and Bitto in connection with the Entegris merger agreement to provide for payment in connection with the merger. The retention bonuses granted to Versum’s executive officers as of the date of the filing of this proxy statement are as follows:

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Quantification of Payments and Benefits to Versum’s Named Executive Officers

The following information, table and the related footnotes present information about the compensation payable to Versum’s named executive officers in connection with the merger.

Golden Parachute Compensation

The following table sets forth the information required by Item 402(t) of Regulation S-K regarding the compensation for Versum’s named executive officers based on the merger, assuming the following:

The amounts below are based on multiple assumptions that may or may not actually occur or be accurate on the relevant date, including assumptions described in footnotes to the table. The amounts below do not reflect certain compensation actions that may occur before the effective time. The actual amounts payable to Versum’s named executive officers, if any, will depend on whether the named executive officer incurs a qualifying termination, the date of termination of the named executive officer’s employment (if applicable), the closing date of the merger, the manner of termination, and the terms of the plans or agreements in effect at such time. More detail on the included payments and benefits are set forth above in this section entitled “— Interests of Versum’s Directors and Executive Officers in the Merger ” beginning on page 64.

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The amounts reflected in the table above with respect to unvested Versum awards held by a named executive officer assume that the number of shares subject to each PSU award, which such number of shares is converted into a deferred cash payment in accordance with the merger agreement based on the $53.00 per share consideration, held by a named executive officer is equal to the PSU award that would have vested based on an estimate of actual performance through May 6, 2019 as follows:

The amounts reflected in the “Equity” column above include accelerated vesting of accrued cash dividends relating to RSU awards granted in respect of Versum’s 2016 fiscal year and accrued as of May 6, 2019 as follows in the table below.

Mr. Loughlin served as Versum’s Senior Vice President, Operations and Supply Chain, through October 31, 2018 and is therefore not entitled to continued health benefits or outplacement benefits in connection with the merger.

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Financing of the Merger

The consummation of the merger is not subject to any financing conditions. Versum anticipates that the total amount of funds necessary to consummate the merger and the related transactions, not including fees and expenses, will be approximately $6.5 billion, including the estimated funds needed to (i) pay Versum stockholders the merger consideration due to them under the merger agreement; (ii) make payments in respect of outstanding Versum equity awards; and (iii) pay the outstanding net indebtedness of Versum, including amounts payable under the notes issued pursuant to the Versum indenture and under the Versum credit agreement. Versum understands that Parent expects to use cash on hand and/or funds available to it under its facilities agreement.

Facilities Agreement

The facilities agreement provides for the following unsecured term loan facilities in an aggregate principal amount of $6.3 billion:

The interest rate on Facility A is equal to LIBOR or EURIBOR plus an applicable margin that varies from 0.15 to 0.95% per annum, depending on the number of months elapsed after the initial drawdown, and subject to increase or decrease by 0.0167% per annum if and at any time there is any change to any solicited long-term credit rating assigned to Parent as compared to that assigned on the date of the facilities agreement. The interest rate on Facility B is equal to LIBOR or EURIBOR plus an applicable margin that varies from 0.40 to 0.70% per annum, depending on the solicited long-term credit rating assigned to Parent.

The facilities agreement contains representations and warranties, undertakings, and events of default customary for credit facilities of this nature. Upon the occurrence of certain events of default, the lenders may cancel their outstanding commitments and declare all or part of the outstanding obligations to be immediately due and payable. The obligation of the lenders to fund loans under the facilities agreement is conditioned upon, among other things, delivery of certain financial statements and customary certificates and legal opinions, the absence of specified defaults, the accuracy in all material respects of specified representations and warranties and there being no change in control of Parent.

Regulatory Approvals

General

Each of Parent and Versum have agreed to cooperate with each other and use, and to cause their respective subsidiaries to use, their respective reasonable best efforts to take or cause to be taken all actions, and to do or cause to be done all things reasonably necessary, proper or advisable on its part under the merger agreement and applicable law to cause the conditions to closing to be satisfied as promptly as reasonably practicable and advisable (and in any event no later than the outside date) and to consummate and make effective the transactions contemplated by the merger agreement as soon as reasonably practicable, including preparing and filing as promptly as reasonably practicable and advisable all documentation to effect all necessary notices, reports and other filings and to obtain as promptly as reasonably practicable all consents necessary or advisable to be obtained from any third party or any governmental entity in order to consummate such transactions.

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Requisite Regulatory Approvals

The completion of the merger is subject to the receipt of antitrust clearance in the United States, and in Austria, China, Germany, Ireland, Japan, Serbia, South Korea and Taiwan. With respect to the United States, the applicable waiting period under the HSR Act for U.S. antitrust purposes expired on April 10, 2019.

At any time before or after consummation of the merger, notwithstanding the expiration or termination of the applicable waiting period under the HSR Act, the Antitrust Division of the U.S. Department of Justice or the U.S. Federal Trade Commission, or any state, could take such action under the antitrust laws as it deems necessary or desirable in the public interest, including seeking to enjoin the completion of the merger, seeking divestiture of substantial assets of the parties or requiring the parties to license, or hold separate, assets or terminate existing relationships and contractual rights. At any time before or after the completion of the merger, and notwithstanding the expiration or termination of the applicable waiting period under the HSR Act, any state could take such action under the antitrust laws as it deems necessary or desirable in the public interest. Such action could include seeking to enjoin the completion of the merger or seeking divestiture of substantial assets of the parties. Private parties may also seek to take legal action under the antitrust laws under certain circumstances.

The merger cannot be completed until Parent and Versum obtain clearance to consummate the merger or applicable waiting periods have expired or been terminated in Austria, China, Germany, Ireland, Japan, Serbia, South Korea and Taiwan. Parent and Versum, in consultation and cooperation with each other, will file notifications, as required with the antitrust authorities in these jurisdictions, as promptly as practicable after the date of the merger agreement. Parent filed a notification with the antitrust authority in Serbia on April 10, 2019. The relevant filings for Germany were submitted on May 6, 2019 and for Ireland and Austria on May 10, 2019. The antitrust authorities in these, and also in other jurisdictions, could take such actions under the applicable antitrust laws as they deem necessary or desirable, including delaying, enjoining or prohibiting the merger or seeking divestiture of substantial assets of the parties or requiring the parties to license, or hold separate, assets or terminate existing relationships and contractual rights. There is no assurance that Parent and Versum will obtain all required antitrust clearances or approvals on a timely basis, if at all.

Each of Parent and Versum is required under the merger agreement to defend through litigation (excluding any appeals) on the merits of any claim asserted in any court, agency or other proceeding by any person or entity (including any governmental antitrust entity) seeking to delay, restrain, prevent, enjoin or otherwise prohibit consummation of the merger. In addition, each of Parent and Versum is required under the merger agreement to take, effect or agree to any regulatory remedy if such regulatory remedy is reasonably necessary, proper or advisable to permit the consummation of the merger and other transactions contemplated by the merger agreement, although no such regulatory remedy is required if it is not conditioned upon the closing of the merger or if such regulatory remedy, individually or in the aggregate with any other regulatory remedy, would reasonably be expected to have a material adverse effect on the business, operations, financial condition or results of operations of (1) Versum and its subsidiaries, taken as whole from and after the effective time, (2) Parent and its subsidiaries (excluding Versum and its subsidiaries), taken as a whole from and after the effective time, but assuming a company the size of, and having the financial and operating metrics of, Versum and its subsidiaries, taken as a whole, or (3) Parent and its subsidiaries (including Versum and its subsidiaries), taken as a whole from and after the effective time, but assuming a company twice the size of, and having the financial and operating metrics twice the size of, Versum and its subsidiaries, taken as a whole, in each case, not taking into account any proceeds received or expected to be received from effecting any such regulatory remedy. For a description of the parties’ obligations with respect to regulatory approvals related to the merger, see the section entitled “ The Merger Agreement—Cooperation; Efforts to Consummate ” beginning on page 97.

CFIUS

Under Section 721 of Title VII of the Defense Production Act of 1950, as amended, which is referred to as Section 721, the President of the United States, acting on his own or through CFIUS, an inter-agency committee chaired by the Secretary of the Treasury and composed of officials from the Departments of Commerce, Defense, Energy, Homeland Security, Justice, State, Treasury and other Executive Branch offices, is authorized to review transactions involving foreign persons that could result in control of a U.S. business engaged in interstate

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commerce in the United States (or, for certain U.S. businesses, investments by foreign persons that do not result in control of the U.S. business) if the President determines that there is credible evidence that the transaction threatens to impair the national security of the United States, and if other provisions of existing law do not provide adequate and appropriate authority to protect national security. CFIUS may clear a proposed transaction unconditionally or impose mitigation requirements as a condition of such clearance. CFIUS may also recommend that the President issue an executive order prohibiting a transaction or requiring a divestiture.

Pursuant to Section 721, a party or parties to a proposed transaction may voluntarily submit a notification of such transaction to CFIUS. In certain cases, submission of a declaration to CFIUS is mandatory pursuant to the interim rule pertaining to a pilot program to review transactions involving foreign persons and certain U.S. businesses that produce, design, test, manufacture, fabricate, or develop one or more critical technologies made effective on November 10, 2018 by the Treasury Department that implements certain authorities granted by the CFIUS reform legislation enacted in August 2018. The President or CFIUS may also initiate a review of a transaction on their own initiative, without any submission by the parties.

The Parties intend to promptly file with CFIUS a notice of the merger in accordance with Section 721. Once CFIUS has accepted the filing, CFIUS will undertake a 45-day review, commencing from the date that CFIUS first accepts the notice. At the end of the 45-day review period, CFIUS may inform the parties that it has concluded all action under Section 721, at which point the review process is complete. Alternatively, CFIUS may determine to undertake an investigation of the merger. An investigation must be completed within 45 calendar days of its initiation (in extraordinary circumstances, the CFIUS Staff Chairperson may extend the investigation for one 15-day period), and at the end of the investigation, CFIUS will either conclude action under Section 721, or may report the matter for decision to the President. Under Section 721, the President must announce a decision within 15 calendar days of the completion of CFIUS’ investigation. In certain cases, CFIUS may identify a national security concern to the parties during the review or investigation period, and if that concern cannot be resolved by a mitigation agreement or otherwise within the initial review and investigation periods, the parties may request permission to voluntarily withdraw and refile their notification in order to allow more time to address national security concerns, which may include the negotiation of a mitigation agreement or condition with respect to such transaction that will allow CFIUS to conclude action under Section 721. Under Section 721 and related regulations, the President and CFIUS have substantial discretion in conducting national security reviews and investigations.

According to the merger agreement, the merger is conditioned on the receipt of CFIUS clearance, where “CFIUS clearance” means, after submission of a mandatory declaration or written notice by the parties with respect to the merger in accordance with the requirements of Section 721 and its implementing regulations, the CFIUS Staff Chairperson (or other representative of CFIUS) shall have notified the parties (i) of CFIUS’ determination that the merger is not a “covered transaction” within the meaning of Section 721, (ii) that there are no unresolved national security concerns with respect to the merger and CFIUS has concluded all action under Section 721 with respect to the merger, or (iii) CFIUS shall have sent a report to the President of the United States requesting the decision of the President of the United States and the period under Section 721 during which the President may announce his decision to take action to suspend, prohibit or place any limitations on the merger shall have expired without any such action being threatened, announced or taken, or the President of the United States shall have announced a decision not to, or otherwise declined to, take any action to suspend or prohibit the merger.

There can be no assurance that CFIUS will conclude that the merger will not impair the national security of the United States. There can be no assurance regarding the ultimate outcome of CFIUS’ review or investigation of the merger.

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Material U.S. Federal Income Tax Consequences

The exchange of Versum common stock for cash in the merger will be a taxable transaction for U.S. federal income tax purposes and may also be taxable under state and local and other tax laws. In general, a U.S. holder whose shares of Versum common stock are converted into the right to receive cash in the merger will recognize capital gain or loss for U.S. federal income tax purposes in an amount equal to the difference, if any, between the amount of cash received with respect to such shares and the U.S. holder’s adjusted tax basis in such shares.

You should read the section entitled “ Material U.S. Federal Income Tax Consequences ” beginning on page 117 and consult your tax advisors regarding the U.S. federal income tax consequences of the merger to you in your particular circumstances, as well as tax consequences arising under the laws of any state, local or foreign taxing jurisdiction.

Exchange of Shares

Prior to the effective time, Parent will appoint an exchange agent (with Versum’s prior approval) to handle the exchange of shares of Versum common stock for the merger consideration.

At the effective time, each share of Versum common stock (other than the Versum excluded shares) will be converted into the right to receive the merger consideration, in accordance with the merger agreement.

After the effective time, shares of Versum common stock will be cancelled and will cease to be outstanding or exist. Each certificate that previously represented shares of Versum common stock (other than the Versum excluded shares) and each book-entry account formerly representing any non-certified shares of Versum common stock (other than the Versum excluded shares) will represent only the right to receive the merger consideration, in accordance with the merger agreement.

As soon as reasonably practicable (but in any event within three business days) after the effective time, the exchange agent will mail each holder of record of a certificate that immediately prior to the effective time represented outstanding shares of Versum common stock: (a) a notice advising such holders of the effectiveness of the merger, (b) a letter of transmittal specifying that delivery will be effected, and risk of loss and title to a certificate will pass, only upon the surrender of the certificate to the exchange agent and (c) instructions for surrendering the applicable certificate in exchange for the merger consideration. After the completion of the merger, shares of Versum common stock represented by any such certificate will be exchanged for the merger consideration in accordance with the merger agreement.

Holders of shares of Versum common stock in book-entry form will not be required to take any specific actions to exchange shares of Versum common stock for the merger consideration. After the completion of the merger, shares of Versum common stock held in book-entry form will be automatically exchanged for the merger consideration in accordance with the merger agreement.

More information can be found in the section entitled “ The Merger Agreement—Exchange of Shares ” beginning on page 83.

Delisting and Deregistration of Versum Common Stock

If the merger is completed, Versum common stock will be delisted from the NYSE and deregistered under the Exchange Act, and Versum will no longer be required to file periodic reports with the SEC with respect to Versum common stock.

Versum has agreed to cooperate with Parent and use its reasonable best efforts to take, or cause to be taken, all actions, and to do or cause to be done all things, reasonably necessary, proper or advisable on its part under applicable laws and rules and policies of the NYSE to enable the delisting by the combined company of the

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shares of Versum common stock from the NYSE and the deregistration of the shares of Versum common stock under the Exchange Act as promptly as practicable after the effective time.

Appraisal Rights

If the merger is completed, Versum stockholders who do not vote for the merger agreement proposal will be entitled to appraisal rights under Section 262 of the DGCL, provided that they strictly comply with the conditions and requirements established therein.

Under Section 262 of the DGCL, Versum stockholders of record who do not wish to accept the $53.00 per share merger consideration provided for in the merger agreement have the right to demand appraisal of their shares of Versum common stock and to receive payment in cash of the fair value of their shares of Versum common stock as of the effective time of the merger, exclusive of any element of value arising from the accomplishment or expectation of the merger, as determined by the Delaware Court of Chancery, together with interest, if any, to be paid upon the amount determined to be such fair value (or, in certain circumstances described below, on the difference between the amount determined to be the fair value and the amount paid to each stockholder entitled to appraisal prior to the entry of judgment in the appraisal proceeding), provided that they comply with the conditions and requirements established in Section 262 of the DGCL. The “fair value” per share of your shares of Versum common stock as determined by the Delaware Court of Chancery in an appraisal proceeding may be more or less than, or the same as, the merger consideration that you are otherwise entitled to receive under the terms of the merger agreement. Versum stockholders who do not vote in favor of the merger agreement proposal, properly demand appraisal for their shares in compliance with the provisions of Section 262 of the DGCL, do not withdraw such demand or otherwise waive or lose their right to appraisal and comply with the other requirements to exercise appraisal rights under the DGCL will be entitled to appraisal rights under the DGCL. Strict compliance with the statutory procedures in Section 262 of the DGCL is required. Failure to follow precisely any of the statutory requirements may result in the loss of your appraisal rights.

This section is intended only as a brief summary of certain provisions of the Delaware statutory procedures that a stockholder must follow in order to seek and perfect appraisal rights. This summary, however, is not a complete statement of all applicable requirements and the law pertaining to appraisal rights under the DGCL, and is qualified in its entirety by reference to Section 262 of the DGCL, the full text of which is attached to this proxy statement as Annex D and is incorporated into this proxy statement by reference, in its entirety. The following summary does not constitute any legal or other advice, nor does it constitute a recommendation that stockholders exercise their appraisal rights under Section 262 of the DGCL. All references in Section 262 of the DGCL and in this summary to a “stockholder” or a “holder” are to the record holder of the shares of Versum common stock as to which appraisal rights are asserted.

Under Section 262 of the DGCL, where a merger agreement is to be submitted for adoption at a meeting of stockholders, Versum must notify the stockholders who were stockholders of record on the record date for notice of such meeting with respect to shares for which appraisal rights are available, not less than 20 days before the meeting to vote on the merger, that appraisal rights will be available. A copy of Section 262 of the DGCL must be included with such notice. This proxy statement constitutes Versum’s notice to our stockholders that appraisal rights are available in connection with the merger and the full text of Section 262 of the DGCL is attached to this proxy statement as Annex D , in compliance with the requirements of Section 262 of the DGCL. If you wish to consider exercising your appraisal rights, you should carefully review the text of Section 262 of the DGCL contained in Annex D . Failure to comply timely and properly with the requirements of Section 262 of the DGCL may result in the loss of your appraisal rights under the DGCL. Moreover, because of the complexity of the procedures for exercising the right to seek appraisal of shares of Versum common stock, Versum believes that if a stockholder is considering exercising such rights, such stockholder should seek the advice of legal counsel.

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If you wish to demand appraisal of your shares of Versum common stock, you must satisfy each of the following conditions:

If you fail to comply with any of the requirements under Section 262 of the DGCL to perfect your appraisal rights and the merger is completed, your shares of Versum common stock will be converted into the right to receive payment of merger consideration for your shares of Versum common stock as provided for in the merger agreement and you will lose your appraisal rights with respect to your shares of Versum common stock.

A holder of shares of Versum common stock wishing to exercise appraisal rights must hold of record the shares of Versum common stock on the date the written demand for appraisal is made and must continue to hold the shares of Versum common stock of record through the effective time of the merger. A stockholder will lose his, her or its appraisal rights if the stockholder transfers the shares for which it is demanding appraisal rights before the effective time. A proxy that is submitted and does not contain voting instructions will, unless revoked, be voted “ FOR ” the merger agreement proposal, and it will result in the loss of the stockholder’s right of appraisal and will nullify any previously delivered written demand for appraisal. Therefore, a stockholder who submits a proxy and who wishes to exercise appraisal rights must either submit a proxy containing instructions to vote “ AGAINST ” the merger agreement proposal or abstain from voting on the merger agreement proposal. Voting against or failing to vote for the merger agreement proposal by itself does not constitute a demand for appraisal within the meaning of Section 262 of the DGCL. The written demand for appraisal must be in addition to and separate from any proxy or vote on the merger agreement proposal.

All demands for appraisal should be addressed to Versum Materials, Inc., Attention: Corporate Secretary, 8555 South River Parkway, Tempe, Arizona 85284, and must be delivered to Versum before the vote is taken to

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approve the merger agreement proposal at the special meeting, and must be executed by, or on behalf of, the record holder of the shares of Versum common stock for which appraisal is demanded. The demand must reasonably inform Versum of the identity of the stockholder and the intention of the stockholder to demand appraisal of his, her or its shares of Versum common stock in connection with the merger. A stockholder’s failure to deliver to Versum the written demand for appraisal prior to the taking of the vote on the merger agreement proposal at the special meeting will result in the loss of appraisal rights.

Only a holder of record of shares of Versum common stock is entitled to demand an appraisal of the shares registered in that holder’s name. Accordingly, to be effective, a demand for appraisal by a stockholder of Versum common stock must be made by, or on behalf of, the record stockholder. The demand should set forth, fully and correctly, the record stockholder’s name as it appears on the stockholder’s stock certificate(s) or in the transfer agent’s records, in the case of uncertificated shares, should specify the stockholder’s mailing address and the number of shares registered in the stockholder’s name. The demand must state that the stockholder intends thereby to demand appraisal of the stockholder’s shares in connection with the merger. The demand cannot be made by the beneficial owner if he or she does not also hold the shares of Versum common stock of record. The beneficial holder must, in such cases, have the registered owner, such as a bank, brokerage firm or other nominee, submit the required demand in respect of those shares of Versum common stock. If you hold your shares of Versum common stock through a bank, brokerage firm or other nominee and you wish to exercise appraisal rights, you should consult with your bank, brokerage firm or the other nominee to determine the appropriate procedures for the making of a demand for appraisal by the nominee and obtaining notice of the effective date of the merger.

If shares of Versum common stock are owned of record in a fiduciary capacity, such as by a trustee, guardian or custodian, execution of a demand for appraisal must be made in that capacity. If the shares of Versum common stock are owned of record by more than one person, as in a joint tenancy or tenancy in common, the demand must be executed by or for all joint owners. An authorized agent, including an authorized agent for two or more joint owners, may execute the demand for appraisal for a stockholder of record; however, the agent must identify the record owner or owners and expressly disclose the fact that, in executing the demand, he or she is acting as agent for the record owner or owners. A record owner, such as a bank, brokerage firm or other nominee, who holds shares of Versum common stock as a nominee for others, may exercise his, her or its appraisal rights with respect to the shares of Versum common stock held for one or more beneficial owners, while not exercising this right for other beneficial owners. In that case, the written demand should state the number of shares of Versum common stock as to which appraisal is sought. Where no number of shares of Versum common stock is expressly mentioned, the demand will be presumed to cover all shares of Versum common stock held in the name of the record owner. If a stockholder holds shares of Versum common stock through a broker who in turn holds the shares through a central securities depository nominee such as Cede & Co., a demand for appraisal of such shares must be made by or on behalf of the depository nominee and must identify the depository nominee as record owner.

Within 10 days after the effective time of the merger, the surviving corporation in the merger must give notice of the date that the merger became effective to each of Versum’s record stockholders who has demanded appraisal in accordance with Section 262 of the DGCL and who did not vote in favor of the merger agreement proposal. At any time within 60 days after the effective time of the merger, any stockholder who has not commenced an appraisal proceeding or joined a proceeding as a named party may withdraw the stockholder’s demand and accept the consideration specified by the merger agreement for that stockholder’s shares of Versum common stock by delivering to the surviving corporation a written withdrawal of the demand for appraisal. However, any such attempt to withdraw the demand made more than 60 days after the effective time of the merger will require written approval of the surviving corporation. No appraisal proceeding in the Delaware Court of Chancery will be dismissed as to any stockholder without the approval of the Delaware Court of Chancery, with such approval conditioned upon such terms as the Delaware Court of Chancery deems just; provided, however that any stockholder who has not commenced an appraisal proceeding or joined that proceeding as a named party may withdraw such stockholder’s demand for appraisal and to accept the terms offered upon the

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merger within 60 days after the effective date of the merger. If the surviving corporation does not approve a request to withdraw a demand for appraisal when that approval is required, or, if the Delaware Court of Chancery does not approve the dismissal of an appraisal proceeding, the stockholder will be entitled to receive only the “fair value” of his, her or its shares of Versum common stock determined in any such appraisal proceeding by the Delaware Court of Chancery, plus interest, if any, which value could be less than, equal to or more than the consideration offered pursuant to the merger agreement.

Within 120 days after the effective time of the merger, but not thereafter, either the surviving corporation or any stockholder who has complied with the requirements of Section 262 of the DGCL and is entitled to appraisal rights under Section 262 of the DGCL may commence an appraisal proceeding by filing a petition in the Delaware Court of Chancery demanding a determination of the fair value of the shares of Versum common stock held by all such stockholders. Upon the filing of the petition by a stockholder, service of a copy of such petition shall be made upon the surviving corporation. The surviving corporation has no obligation to file such a petition, has no present intention to file a petition and holders should not assume that the surviving corporation will file a petition. Accordingly, it is the obligation of the holders of Versum common stock to initiate all necessary petitions to perfect their appraisal rights in respect of shares of Versum common stock within the time prescribed in Section 262 of the DGCL and the failure of a stockholder to file such a petition within the period specified in Section 262 of the DGCL could nullify the stockholder’s previous written demand for appraisal and result in the loss of appraisal rights. In addition, within 120 days after the effective time of the merger, any stockholder who has properly complied with the requirements of Section 262 of the DGCL and who did not vote in favor of the merger agreement proposal, will be entitled to receive from the surviving corporation, upon written request, a statement setting forth the aggregate number of shares of Versum common stock not voted in favor of the merger agreement proposal and with respect to which demands for appraisal have been received and the aggregate number of holders of such shares. The statement must be mailed within 10 days after such written request has been received by the surviving corporation or within 10 days after the expiration of the period for delivery of demands for appraisal, whichever is later. A person who is the beneficial owner of shares of Versum common stock held either in a voting trust or by a nominee on behalf of such person for which appraisal has been properly demanded may, in such person’s own name, file a petition for appraisal or request from the surviving corporation such statement.

If a petition for appraisal is duly filed by a stockholder and a copy of the petition is delivered to the surviving corporation, then the surviving corporation will be obligated, within 20 days after receiving service of a copy of the petition, to file with the Delaware Register in Chancery a duly verified list containing the names and addresses of all stockholders who have demanded an appraisal of their shares of Versum common stock and with whom agreements as to the value of their shares of Versum common stock have not been reached. After notice to stockholders who have demanded appraisal from the Register in Chancery, if such notice is ordered by the Delaware Court of Chancery, the Delaware Court of Chancery will conduct a hearing upon the petition and determine those stockholders who have become entitled to the appraisal rights provided by Section 262 of the DGCL. Upon application by the surviving corporation or by any stockholder entitled to participate in the appraisal proceeding, the Delaware Court of Chancery may, in its discretion, proceed to trial upon the appraisal prior to the final determination of the stockholders entitled to an appraisal. The Delaware Court of Chancery may require stockholders who have demanded appraisal of their shares of Versum common stock to submit their stock certificates to the Register in Chancery for notation of the pendency of the appraisal proceedings; and if any stockholder fails to comply with that direction, the Delaware Court of Chancery may dismiss the proceedings as to that stockholder. In addition, the Delaware Court of Chancery will dismiss the proceedings as to all holders of such shares who are otherwise entitled to appraisal rights unless (1) the total number of shares of Versum common stock entitled to appraisal exceeds 1% of the outstanding shares of Versum common stock, or (2) the value of the consideration provided in the merger for such total number of shares of Versum common stock exceeds $1 million.

After determination of the stockholders entitled to appraisal of their shares of Versum common stock, the Delaware Court of Chancery will conduct an appraisal proceeding to determine the “fair value” of the shares of

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Versum common stock as of the effective time of the merger after taking into account all relevant factors exclusive of any element of value arising from the accomplishment or expectation of the merger, together with interest, if any, to be paid upon the amount determined to be the fair value (or, in certain circumstances described below, on the difference between the amount determined to be the fair value and the amount paid to each stockholder entitled to appraisal prior to the entry of judgment in the appraisal proceeding). When the fair value has been determined, the Delaware Court of Chancery will direct the payment of such value (with interest, if any) by the surviving corporation to the stockholders entitled thereto, in the case of holders of uncertificated stock forthwith, and in the case of holders of shares represented by certificates upon surrender by those stockholders of the certificates representing their shares of Versum common stock. Unless the Delaware Court of Chancery in its discretion determines otherwise for good cause shown, interest from the effective date of the merger through the date of payment of the judgment shall be compounded quarterly and shall accrue at 5% over the Federal Reserve discount rate (including any surcharge) as established from time to time during the period between the effective time of the merger and the date of payment of the judgment. At any time before the entry of judgment in the proceedings, the surviving corporation may pay to each stockholder entitled to appraisal an amount in cash, in which case interest shall accrue thereafter as described herein only upon the sum of (1) the difference, if any, between the amount so paid and the fair value of the shares as determined by the Delaware Court of Chancery, and (2) interest theretofore accrued, unless paid at that time.

You should be aware that an investment banking opinion as to the fairness from a financial point of view of the consideration to be received in a sale transaction, such as the merger, is not an opinion as to fair value under Section 262 of the DGCL. Although we believe that the per share merger consideration is fair, no representation is made as to the outcome of the appraisal of fair value as determined by the Delaware Court of Chancery and stockholders should recognize that such an appraisal could result in a determination of a value higher or lower than, or the same as, the per share merger consideration. Moreover, none of the surviving corporation, Parent or Merger Sub anticipates offering more than the per share merger consideration to any stockholder exercising appraisal rights and reserve the right to assert, in any appraisal proceeding, that, for purposes of Section 262 of the DGCL, the “fair value” of a share of Versum common stock is less than the per share merger consideration.

In determining “fair value,” the Delaware Court of Chancery is required to take into account all relevant factors. Section 262 of the DGCL provides that fair value is to be “exclusive of any element of value arising from the accomplishment or expectation of the merger.” In Weinberger v. UOP, Inc., the Delaware Supreme Court discussed the factors that could be considered in determining fair value in an appraisal proceeding, stating that “proof of value by any techniques or methods which are generally considered acceptable in the financial community and otherwise admissible in court” should be considered and that “[f]air price obviously requires consideration of all relevant factors involving the value of a company.” The Delaware Supreme Court has stated that, in making this determination of fair value, the court must consider market value, asset value, dividends, earnings prospects, the nature of the enterprise and any other factors that could be ascertained as of the date of the merger that throw any light on future prospects of the merged corporation. Section 262 of the DGCL provides that fair value is to be “exclusive of any element of value arising from the accomplishment or expectation of the merger.” In Cede & Co. v. Technicolor, Inc., the Delaware Supreme Court stated that such exclusion is a “narrow exclusion [that] does not encompass known elements of value,” but which rather applies only to the speculative elements of value arising from such accomplishment or expectation. In Weinberger, the Delaware Supreme Court construed Section 262 of the DGCL to mean that “elements of future value, including the nature of the enterprise, which are known or susceptible of proof as of the date of the merger and not the product of speculation, may be considered.”

Costs of the appraisal proceeding (which do not include attorneys’ fees or the fees and expenses of experts) may be determined by the Delaware Court of Chancery and imposed upon the surviving corporation and the stockholders participating in the appraisal proceeding by the Delaware Court of Chancery, as it deems equitable in the circumstances. Upon the application of a stockholder, the Delaware Court of Chancery may order all or a portion of the expenses incurred by any stockholder in connection with the appraisal proceeding, including, without limitation, reasonable attorneys’ fees and the fees and expenses of experts used in the appraisal

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proceeding, to be charged pro rata against the value of all shares of Versum common stock entitled to appraisal. Any stockholder who demanded appraisal rights will not, after the effective time of the merger, be entitled to vote shares of Versum common stock subject to that demand for any purpose or to receive payments of dividends or any other distribution with respect to those shares of Versum common stock, other than with respect to payment as of a record date prior to the effective time of the merger. If no petition for appraisal is filed within 120 days after the effective time of the merger, or if the stockholder otherwise fails to perfect, successfully withdraws or loses such holder’s right to appraisal, then the right of that stockholder to appraisal will cease and that stockholder’s shares of Versum common stock will be deemed to have been converted at the effective time of the merger into the right to receive the merger consideration for his, her or its shares of Versum common stock pursuant to the merger agreement.

Failure to comply strictly with all of the procedures set forth in Section 262 of the DGCL will result in the loss of a stockholder’s appraisal rights.

In view of the complexity of Section 262 of the DGCL, Versum stockholders who may wish to pursue appraisal rights should consult their legal and financial advisors.

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THE MERGER AGREEMENT

The following description sets forth the principal terms of the merger agreement, which is attached as Annex A and is incorporated by reference into this proxy statement. The rights and obligations of the parties are governed by the express terms and conditions of the merger agreement and not by this description, which is summary by nature. This description does not purport to be complete and is qualified in its entirety by reference to the complete text of the merger agreement. You are encouraged to read the merger agreement carefully and in its entirety, as well as this proxy statement and any documents incorporated by reference herein, before making any decisions regarding any of the proposals described in this proxy statement. This section is intended to provide you with information regarding the terms of the merger agreement. Accordingly, the representations, warranties, covenants and other agreements in the merger agreement should not be read alone, and you should read the information provided elsewhere in this proxy statement and in the public filings Versum makes with the SEC, as described in the section entitled “ Where You Can Find More Information ” beginning on page 122.

Explanatory Note Regarding the Merger Agreement

The merger agreement and this summary of terms are included to provide you with information regarding the terms of the merger agreement. Factual disclosures about Versum contained in this proxy statement or in the public reports of Versum filed with the SEC may supplement, update or modify the factual disclosures about Versum contained in the merger agreement. The representations, warranties and covenants made in the merger agreement by Parent and Versum were qualified and subject to important limitations agreed to by Parent and Versum in connection with negotiating the terms of the merger agreement. In particular, in your review of the representations and warranties contained in the merger agreement and described in this summary, it is important to bear in mind that the representations and warranties were negotiated with the principal purpose of establishing circumstances in which a party to the merger agreement may have the right not to consummate the merger if the representations and warranties of the other party prove to be untrue due to a change in circumstance or otherwise, and allocating risk between the parties to the merger agreement, and were not intended by the parties to the merger agreement to be a characterization of the actual state of facts or condition of Parent or Versum, except as expressly stated in the merger agreement. The representations and warranties also may be subject to a contractual standard of materiality different from that generally applicable to stockholders and reports and documents filed with the SEC and in some cases were qualified by the matters contained in the confidential disclosures that Parent and Versum each delivered in connection with the merger agreement, which disclosures were not reflected in the merger agreement. Moreover, information concerning the subject matter of the representations and warranties, which do not purport to be accurate as of the date of this proxy statement, may have changed since the date of the merger agreement and subsequent developments or new information qualifying a representation or warranty may have been included in this proxy statement or in the respective public filings made by Versum with the SEC.

Additional information about Parent and Versum may be found elsewhere in this proxy statement and in the public filings Versum makes with the SEC. See the section entitled “ Where You Can Find More Information ” beginning on page 122.

Structure of the Merger

The merger agreement provides for the merger of Merger Sub with and into Versum. At the effective time as a result of the merger, the separate existence of Merger Sub will cease, and Versum will continue its existence under the laws of the State of Delaware as the surviving corporation and become a wholly-owned subsidiary of Parent.

Completion and Effectiveness of the Merger

The closing of the merger will take place on the fourth business day following the day on which the last to be satisfied or (to the extent permissible) waived of the conditions for completion of the merger set forth in the

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merger agreement (other than those conditions that by their nature must be satisfied or waived (to the extent permissible) at the closing (so long as such conditions are reasonably capable of being satisfied), but subject to the satisfaction or waiver of those conditions) is satisfied or waived (to the extent permissible) in accordance with the merger agreement or on such other date as Versum and Parent may mutually agree in writing.

As soon as practicable following, and on the date of, the closing, Parent and Versum will cause a certificate of merger relating to the merger to be executed, acknowledged and filed with the Secretary of State of the State of Delaware as provided in Section 251 of the DGCL. The merger will become effective at the time when the certificate of merger has been duly filed with and accepted by the Secretary of State of the State of Delaware or at such later date and time as may be agreed by Parent and Versum in writing and specified in the certificate of merger.

Parent and Versum are working to complete the merger prior to the outside date of April 13, 2020 (subject to extension in certain circumstances to July 13, 2020 pursuant to the terms of the merger agreement). It is possible that factors outside the control of both companies could result in the merger being completed at a different time, or not at all.

Merger Consideration

At the effective time, by virtue of the merger and without any action on the part of the parties or any holder of any capital stock of Versum, each share of Versum common stock issued and outstanding immediately prior to the effective time (other than Versum excluded shares) will be converted into the right to receive the merger consideration.

At the effective time, all treasury shares and Parent owned shares will be cancelled and will cease to exist, and no payment will be made in respect of such shares.

Treatment of Equity Awards

At the effective time, each stock option that is outstanding immediately prior to the effective time will be canceled for the right of the option holder to receive a cash payment equal to the product of (i) the number of shares of Versum common stock subject to such stock option, and (ii) the excess, if any, of the merger consideration, over the exercise price of such stock option (with outstanding stock options whose exercise price is equal to or greater than the merger consideration canceled for no consideration or payment).

At the effective time, each outstanding RSU award and each outstanding PSU award will be canceled and be converted into the right of the RSU award holder or PSU award holder, as applicable, to receive a deferred cash payment equal to the product of (i) the number of shares of Versum common stock underlying such RSU award or PSU award and (ii) the merger consideration. For PSU awards, the number of shares in the immediately preceding sentence will be determined based on actual performance through a shortened performance period ending immediately prior to the effective time, as determined in the good faith discretion of the compensation committee of the Versum board of directors. The deferred cash payments will (i) vest and settle on terms (including acceleration events) at least as favorable as were applicable to the corresponding RSU award or PSU award, as applicable, immediately prior to the effective time, except that deferred cash payments relating to PSU awards will no longer be subject to performance-based vesting criteria and (ii) other than RSU awards that were converted from equity-based awards granted by Air Products in connection with the spinoff, accrue interest at a rate equal to LIBOR plus 2.0% per annum, computed in accordance with the terms of the applicable award agreement evidencing such RSU award or PSU award, as applicable. Each deferred cash payment will vest in full on the original vesting date or, if the holder experiences a “covered termination” following the effective time and prior to the original vesting date, on the date of such “covered termination,” with the deferred cash payment settled in cash as soon as practicable, but in no event later than 10 business days, following such “covered

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termination,” or such later time as required to comply with Section 409A of the Code. For employees of Versum and its subsidiaries, a “covered termination” means a termination by Versum or one of its subsidiaries or their successor in interest without “cause” or, to the extent good reason rights are provided for in the award agreement (or employment or similar agreement) applicable to the corresponding RSU award or PSU award, a resignation by the employee for “good reason” (as such terms are defined in the applicable Versum agreement), in either case, during the 24-month period following the effective time. For non-employee directors of Versum, a “covered termination” means the termination of their service as a director for any reason at or following the effective time.

At the effective time, each DSU award under the Director DCP will be fully vested and be converted into the right to receive a cash amount equal to (i) the number of shares of Versum common stock covered by the DSU award and (ii) the merger consideration, with such cash payment made to the holder no later than 30 business days following the effective time.

The merger agreement prescribes certain treatment of Versum’s existing equity awards, a summary of which is described in the section entitled “ The Merger—Interests of Versum’s Directors and Executive Officers in the Merger ” beginning on page  64.

Exchange of Shares

Exchange Agent

Parent will deposit or cause to be deposited, by wire transfer of immediately available funds, with an exchange agent selected by Parent (with Versum’s prior approval, which approval will not be unreasonably withheld, conditioned or delayed), for the benefit of the holders of Versum common stock, as promptly as reasonably practicable following the effective time, an aggregate amount of cash in U.S. dollars sufficient for the exchange agent to deliver the amounts required to be delivered in respect of shares of Versum common stock eligible to receive the merger consideration pursuant to the terms of the merger agreement. Such cash is referred to as the exchange fund.

Exchange Procedures

With respect to certificates formerly representing shares of Versum common stock, as promptly as reasonably practicable (but in any event within three business days) after the effective time, Parent will cause the exchange agent to mail to each holder of record of each such certificate:

Upon surrender to the exchange agent of such certificate (or affidavit of loss in lieu of such certificate as provided in the merger agreement) together with a duly executed and completed letter of transmittal and such other documents as may reasonably be required pursuant to such instructions, the holder of such certificate will be entitled to receive as promptly as practicable (but in any event within three business days) a cash amount in immediately available funds (after giving effect to any required tax withholdings as provided in the merger agreement) that such holder has the right to receive pursuant to the merger agreement. Any certificate so surrendered will be cancelled by the exchange agent.

With respect to shares of Versum common stock held in book-entry form not held through DTC, as promptly as reasonably practicable (but in any event within three business days) after the effective time, Parent will cause the exchange agent to mail to each holder of record of any such share:

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Upon surrender to the exchange agent of book-entry shares not held through DTC in accordance with the terms of the letter of transmittal and accompanying instructions, Parent or Merger Sub will cause the exchange agent to pay and deliver to each holder of such book-entry shares not held through DTC, as promptly as reasonably practicable (but in any event within three business days) after the effective time a cash amount in immediately available funds (after giving effect to any required tax withholdings as provided in the merger agreement) that such holder has the right to receive pursuant to the merger agreement.

With respect to shares of Versum common stock held in book-entry form held through DTC, Parent and Versum will cooperate to establish procedures with the exchange agent and DTC to ensure that the exchange agent will transmit to DTC or its nominees as soon as practicable after the effective time, upon surrender of shares of Versum common stock held of record by DTC or its nominees in accordance with DTC’s customary surrender procedures, the merger consideration that such holder has the right to receive pursuant to the merger agreement.

No interest will be paid or accrued on any amount payable for shares of Versum common stock pursuant to the merger agreement.

From and after the effective time, there will be no transfers on the stock transfer books of Versum of the shares of Versum common stock that were outstanding immediately prior to the effective time. From and after the effective time, the holders of certificates formerly representing shares of Versum common stock or shares of Versum common stock held in book-entry form will cease to have any rights with respect to such shares of Versum common stock except as otherwise provided in the merger agreement or by applicable law. If, after the effective time, certificates are presented to the combined company for any reason, they will be cancelled and exchanged as provided in the merger agreement.

Termination of the Exchange Fund

Any portion of the exchange fund that remains unclaimed as of the date that is six months after the closing date will be delivered to Parent. Any holder of shares of Versum common stock who has not by that point complied with the terms of the exchange procedures in the merger agreement may thereafter look only to Parent for delivery of the merger consideration that such holder has the right to receive pursuant to the merger agreement.

None of Parent, Versum, the combined company or the exchange agent will be liable to any person in respect of any portion of the merger consideration delivered to a public official pursuant to any applicable abandoned property, escheat or similar law. If any certificate formerly representing shares of Versum common stock or share of Versum common stock held in book-entry form has not been surrendered prior to seven years after the effective time, or immediately prior to such earlier date on which any cash that a holder of any such shares has the right to receive pursuant to the merger agreement in respect thereof would otherwise escheat to or become property of any governmental entity, any such cash will, to the extent permitted by applicable law, become the property of Parent, free and clear of all claims or interests of any person previously entitled thereto.

Lost, Stolen or Destroyed Share Certificates

In the event that any certificate formerly representing shares of Versum common stock is lost, stolen or destroyed, upon the making of an affidavit of that fact by the person claiming such certificate to be lost, stolen or destroyed and the posting by such person of a bond in customary amount and upon such terms as may be required as indemnity against any claim that may be made against it with respect to such certificate, the exchange agent will issue in exchange for such lost, stolen or destroyed certificate, the merger consideration payable or issuable pursuant to the merger agreement, as if such lost, stolen or destroyed certificate had been surrendered.

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Appraisal Rights

No person who has perfected a demand for appraisal rights pursuant to Section 262 of the DGCL will be entitled to receive the merger consideration with respect to the dissenting shares owned by such person unless and until such person has effectively withdrawn or lost such person’s right to appraisal under the DGCL, at which time such dissenting shares will be treated as if they had been converted into and become exchangeable for the right to receive the merger consideration, without interest and after giving effect to any required tax withholdings as provided in the merger agreement. Versum is required to give Parent (i) prompt notice of any written demands received by Versum for appraisal, attempted withdrawals of such demands, and any other instruments served pursuant to applicable law that are received by Versum relating to stockholders’ rights of appraisal and (ii) the opportunity to participate in all negotiations and proceedings with respect to demand for appraisal under the DGCL. Versum will not, except with the prior written consent of Parent, voluntarily make any payment with respect to any demands for appraisal, offer to settle or settle any such demands or approve any withdrawal of any such demands.

Withholding Rights

Each of Parent, Merger Sub, the combined company, the exchange agent and any other withholding agent will be entitled to deduct and withhold from the consideration otherwise payable pursuant to the merger agreement to any holder of shares of Versum common stock and Versum equity awards such amounts as it is required to deduct and withhold with respect to the making of such payment under the Code, or any other applicable state, local or foreign tax law.

Adjustments to Prevent Dilution

If, from the date of the merger agreement to the effective time, the issued and outstanding shares of Versum common stock or securities convertible or exchangeable into or exercisable for shares of Versum common stock have been changed into a different number of shares or securities or a different class by reason of any reclassification, stock split (including a reverse stock split), stock dividend or distribution, recapitalization, merger, issuer tender or exchange offer, or other similar transaction, or a stock dividend with a record date within such period has been declared, then the merger consideration will be equitably adjusted to provide the holders of shares of Versum common stock the same economic effect as contemplated by the merger agreement prior to such event.

Transfers of Ownership

If a transfer of ownership of shares of Versum common stock is not registered in Versum’s stock transfer books or ledger, or if the merger consideration is to be paid to an individual other than that named in the certificates surrendered or transferred, the merger consideration may be paid to a person other than the person in whose name the certificate so surrendered or transferred is registered in the stock transfer books or ledger only if (i) such certificate is properly endorsed and is otherwise in proper form for surrender and transfer and (ii) the person requesting the payment has paid Parent any transfer taxes required by reason of the payment of the merger consideration to a person other than the registered holder of such certificate, or established to the satisfaction of Parent that such transfer taxes have been paid or are otherwise not payable.

Representations and Warranties

The merger agreement contains representations and warranties made by Versum to Parent and by Parent to Versum. Certain of the representations and warranties in the merger agreement are subject to materiality or material adverse effect qualifications (that is, they will not be deemed to be inaccurate or incorrect unless their failure to be true or correct is material or would result in a material adverse effect on the party making such representation or warranty). In addition, certain of the representations and warranties in the merger agreement are

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subject to knowledge qualifications, which means that those representations and warranties would not be deemed untrue, inaccurate or incorrect as a result of matters of which certain officers of the party making the representation did not have actual knowledge after reasonable inquiry. Furthermore, each of the representations and warranties is subject to the qualifications set forth on the disclosure letter delivered to Parent by Versum, in the case of representations and warranties made by Versum, as well as the reports of Versum filed with or furnished to the SEC during the period from January 1, 2018 through the business day prior to the date of the merger agreement (excluding any disclosures set forth or referenced in any risk factor section or in any other section to the extent they are forward-looking statements or cautionary, predictive or forward-looking in nature).

In the merger agreement, Versum has made representations and warranties to Parent, regarding:

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In the merger agreement, Parent and Merger Sub have made representations and warranties to Versum regarding:

For purposes of the merger agreement, a “material adverse effect” means any effect that is materially adverse to the business, condition (financial or otherwise) or results of operations of Versum and its subsidiaries, taken as a whole; except that none of the following, alone or in combination, will be deemed to constitute a material adverse effect, or be taken into account in determining whether a material adverse effect has occurred or would reasonably be expected to occur:

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Notwithstanding the exceptions listed above, with respect to the first, second, sixth and eighth exceptions listed, such effect will be taken into account in determining whether a material adverse effect has occurred if it disproportionately adversely affects Versum and its subsidiaries, taken as a whole, compared to other companies and their respective subsidiaries, taken as a whole, of comparable size, operating in the industries in which Versum and its subsidiaries operate, but, in such event, only the incremental disproportionate impact of any such effect will be taken into account in determining whether a material adverse effect has occurred.

Conduct of Business Prior to the Effective Time

Versum has agreed as to itself and its subsidiaries that, after the date of the merger agreement and prior to the effective time (except as approved in writing by Parent (which approval may not be unreasonably withheld, conditioned or delayed)) except as otherwise expressly contemplated by the merger agreement or as set forth in Versum’s disclosure letter, the business of Versum and its subsidiaries will be conducted in all material respects in the ordinary course and, to the extent consistent therewith, it and its subsidiaries will use their respective commercially reasonable efforts to preserve their business organizations intact and maintain existing relations and goodwill with governmental entities, customers, suppliers, licensors, licensees, distributors, creditors,

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lessors, employees and business associates and keep available the services of its and its subsidiaries’ present officers, employees and agents.

From the date of the merger agreement until the effective time, subject to certain exceptions and except as expressly contemplated by the merger agreement, required by applicable law, approved in writing by Parent (which approval may not be unreasonably withheld, conditioned or delayed) or set forth in Versum’s disclosure letter, Versum has agreed not to and to cause its subsidiaries not to:

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in each case in response to any unanticipated and subsequently discovered events, occurrences or developments (except that Versum will use its reasonable best efforts to consult with Parent prior to making or agreeing to any such capital expenditure);

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No Solicitation of Acquisition Proposals

Versum has agreed that neither Versum nor any its subsidiaries, will, and that it will cause its and its subsidiaries’ directors, officers and employees not to, and not permit its investment bankers, attorneys, accountants and other advisors or representatives to, which directors, officers, employees, investment bankers, attorneys, accountants and other advisors or representatives are collectively referred to as representatives, directly or indirectly:

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An “acquisition proposal” means:

Notwithstanding the restrictions described above, prior to the time, but not after, the required Versum vote is obtained, in response to an unsolicited, bona fide written acquisition proposal received after the date of the merger agreement that did not arise from or in connection with a breach of the above obligations, Versum may: