CISS C3is Inc

As filed with the U.S. Securities and Exchange Commission on December 10, 2024.

Registration No. 333-276868

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

POST-EFFECTIVE AMENDMENT NO. 2

TO

Form F-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

C3is Inc.

(Exact name of registrant as specified in its charter)

331 Kifissias Avenue

Erithrea 14561 Athens, Greece

(Address of principal executive offices)

Dr. Diamantis Andriotis

331 Kifissias Avenue

Erithrea 14561, Athens, Greece

Telephone: (011) (30) (210) 625 0001

Facsimile: (011) (30) (210) 625 0018

(Name, Telephone, E-mail and/or Facsimile number and Address of Company Contact Person)

Puglisi & Associates

850 Library Avenue, Suite 204

Newark, Delaware 19711

(302) 738-6680

(Name, address and telephone number of agent for service)

Copies to:

Finn Murphy, Esq.

Goodwin Procter LLP

The New York Times Building

620 Eighth Avenue

New York, New York 10018

(212) 459-7257

Approximate date of commencement of proposed sale to the public:

From time to time after this Registration Statement becomes effective.

If any of the securities being registered on this Form are being offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933.

Emerging growth company. ☒

If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards† provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☒

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE

This Post-Effective Amendment No. 2 to Form F-1 (this “Post-Effective Amendment”) is being filed to update the Registration Statement on Form F-1 (Registration No. 333-276868) (the “Original Registration Statement”), which became effective on March 14, 2024, as amended by Post-Effective Amendment No. 1 to Form F-1 filed with the U.S. Securities and Exchange Commission (the “SEC”), to incorporate by reference the Registrant’s Annual Report on Form 20-F for the fiscal year ended December 31, 2023 (the “Annual Report”), which was filed with the SEC on April 30, 2024, and the Registrant’s Current Report on Form 6-K filed with the SEC on September 30, 2024 (the “Current Report”). Accordingly, this Post-Effective Amendment amends the Original Registration Statement. Prior to the filing of the Current Report, (1) the underwritten offering (the “Underwritten Offering”) to which the Original Registration Statement related was completed, including the partial exercise of the underwriters’ overallotment option, and (2) Class C-1 Warrants were exercised for an aggregate of $5,020,300 of shares of common stock and Class C-2 Warrants were exercised for an aggregate of $1,578,198. Accordingly, this Post-Effective Amendment relates only to the exercise of the remaining Class C-1 Warrants which are exercisable for up to an aggregate of $38,439 of shares of common stock, and Class C-2 Warrants which are exercisable for up to an aggregate of $9,888,306 of shares of common stock, on a split-adjusted basis, that were issued as a component of the units in the Underwritten Offering.

The applicable registration fee was paid in connection with the filing of the Original Registration Statement on February 5, 2024.

All share information in this Post-Effective Amendment No. 1 reflects the 1-for-100 reverse stock split of the Company’s common stock effected at 11:59 p.m., Eastern Time, on April 11, 2024.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

PROSPECTUS

SUBJECT TO COMPLETION PRELIMINARY

PROSPECTUS DATED DECEMBER 10, 2024

Up to $9,926,745 of Common

Shares issuable upon the exercise of

outstanding Class C-1 Warrants and Class C-2 Warrants

C3IS INC.

This prospectus relates to the issuance of up to $9,926,745 shares of common stock issuable upon the exercise of outstanding Class C-1 Warrants to purchase common stock with an aggregate exercise price of $38,439, which we refer to as the Class C-1 Warrants, and outstanding Class C-2 Warrants to purchase common stock with an aggregate exercise price of $9,888,306, which we refer to as the Class C-2 Warrants. The Class C-1 Warrants and Class C-2 Warrants were issued in connection with our underwritten public offering which closed on March 19, 2024, each currently have an exercise price of $1.2573 per common share and are currently exercisable for an aggregate of 30,572 and 7,864,715 shares of common stock, respectively. The exercise price and number of shares of common stock issuable upon exercise of the Class C-1 Warrants and the Class C-2 Warrants each may be adjusted upon the occurrence of certain events; however, the aggregate exercise price of such warrants shall not be increased.

Each Class C-1 Warrant will expire on March 19, 2029, which is five years from issuance. Each Class C-2 Warrant will expire on March 19, 2029, which is five years from issuance.

Our common stock are traded on the Nasdaq Capital Market under the symbol “CISS.” The last reported sale price of our common stock on the Nasdaq Capital Market on December 9, 2024, was $0.74 per share.

Investing in our securities involves risks. See “Risk Factors” beginning on page 9 of this prospectus and the “Risk Factors” section of our Annual Report on Form 20-F that is incorporated by reference into this prospectus before you make an investment in our securities.

We are an “emerging growth company” as that term is used in the Securities Act of 1933, as amended (the “Securities Act”), and, as such, we may elect to comply with certain reduced public company reporting requirements. See “Risk Factors” and “Prospectus Summary—Implications of Being an Emerging Growth Company.”

Neither the U.S. Securities and Exchange Commission (the “SEC”) nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Prospectus dated    , 2024. 

TABLE OF CONTENTS

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ABOUT THIS PROSPECTUS

You should rely only on the information contained in this prospectus and in any free writing prospectus filed with the SEC, as well as any amended prospectus and any prospectus supplement, together with additional information described under the headings “Additional Information” and “Incorporation of Certain Information By Reference. We have not, and the underwriters have not, authorized anyone to provide you with different information or to make representations other than those contained in this prospectus. If anyone provides you with different or inconsistent information, you should not rely on it. We are not, and the underwriters are not, making an offer to sell these securities in any jurisdiction where the offer is not permitted. You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front of this prospectus.

Unless otherwise indicated, references to “C3is,” the “Company,” “we,” “our,” “us” or similar terms refer to the registrant, C3is Inc., and its subsidiaries, except where the context otherwise requires.

WHERE YOU CAN FIND ADDITIONAL INFORMATION

We have filed with the SEC a registration statement on Form F-1 regarding the securities being offered pursuant to this prospectus. This prospectus does not contain all of the information found in the registration statement. For further information regarding us and the securities offered by this prospectus, you may wish to review the full registration statement, including its exhibits.

We are subject to the information requirements of the Securities Exchange Act of 1934, and, in accordance therewith, we will be required to file with the SEC annual reports on Form 20-F within four months of our fiscal year-end, and provide to the SEC other material information on Form 6-K. These reports and other information may be inspected and copied at the public reference facilities maintained by the SEC or obtained from the SEC’s website as provided above. We expect to make our periodic reports and other information filed with or furnished to the SEC available, free of charge, through our website as soon as reasonably practicable after those reports and other information are electronically filed with or furnished to the SEC.

As a foreign private issuer, we are exempt under the Exchange Act from, among other things, certain rules prescribing the furnishing and content of proxy statements, and our executive officers, directors and principal shareholders are exempt from the reporting and short-swing profit recovery provisions contained in Section 16 of the Exchange Act. In addition, we will not be required under the Exchange Act to file periodic reports and financial statements with the SEC as frequently or as promptly as U.S. companies whose securities are registered under the Exchange Act, including the filing of quarterly reports or current reports on Form 8-K. However, we intend to furnish or make available to our shareholders annual reports containing our audited financial statements prepared in accordance with U.S. GAAP and make available to our shareholders quarterly reports containing our unaudited interim financial information for the first three fiscal quarters of each fiscal year. Our annual report will contain a detailed statement of any transactions between us and our related parties.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” the information we file with the SEC. This means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be part of this prospectus.

This prospectus incorporates by reference the following documents:

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We will provide, free of charge upon written or oral request, to each person to whom this prospectus is delivered, including any beneficial owner of the securities, a copy of any or all of the information that has been incorporated by reference into this prospectus, but which has not been delivered with the prospectus. Copies of these documents also may be obtained on the “Investors” section of our website at http://c3is.pro. The information contained on or linked to or from our website is not incorporated by reference into this prospectus and should not be considered part of this prospectus. Requests for such information should be made to us at the following address:

C3is Inc.

331 Kifissias Avenue

Erithrea 14561, Athens, Greece

Telephone: (011) (30) (210) 625 0001

Facsimile: (011) (30) (210) 625 0018

Attention: Chief Financial Officer

You should assume that the information appearing in this prospectus and any accompanying prospectus supplement, as well as the information we previously filed with the SEC and incorporated by reference, is accurate as of the dates on the front cover of those documents only. Our business, financial condition and results of operations and prospects may have changed since those dates.

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FORWARD-LOOKING STATEMENTS

This prospectus contains forward-looking statements. These forward-looking statements include information about possible or assumed future results of our operations or our performance. Words such as “expects,” “intends,” “plans,” “believes,” “anticipates,” “estimates,” and variations of such words and similar expressions are intended to identify the forward-looking statements. Although we believe that the expectations reflected in such forward-looking statements are reasonable, no assurance can be given that such expectations will prove to have been correct. These statements involve known and unknown risks and are based upon a number of assumptions and estimates which are inherently subject to significant uncertainties and contingencies, many of which are beyond our control. Actual results may differ materially from those expressed or implied by such forward-looking statements. Forward-looking statements include, but are not limited to, statements regarding:

WE UNDERTAKE NO OBLIGATION TO PUBLICLY UPDATE OR REVISE ANY FORWARD- LOOKING STATEMENTS CONTAINED IN THIS PROSPECTUS OR THE DOCUMENTS TO WHICH WE REFER YOU IN THIS PROSPECTUS, TO REFLECT ANY CHANGE IN OUR EXPECTATIONS WITH RESPECT TO SUCH STATEMENTS OR ANY CHANGE IN EVENTS, CONDITIONS OR CIRCUMSTANCES ON WHICH ANY STATEMENT IS BASED, EXCEPT AS REQUIRED BY LAW.

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MARKET DATA

The Company uses market data throughout this prospectus. The Company has obtained certain market data from publicly available information and industry publications. These sources generally state that the information they provide has been obtained from sources believed to be reliable, but the accuracy and completeness of the information are not guaranteed. The forecasts and projections are based on industry surveys and the preparers’ experience in the industry, and there is no assurance that any of the projections or forecasts will be achieved. The Company believes that the surveys and market research others have performed are reliable, but the Company has not independently verified this information.

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RISK FACTORS

Any investment in our securities involves a high degree of risk. In addition to the other information included or incorporated by reference in this prospectus, you should consider carefully the following factors and the factors set forth under the heading “Item 3. Key Information-Risk Factors” in our Annual Report on Form 20-F for the year ended December 31, 2023, filed with the SEC on April 30, 2024 and incorporated herein by reference, before making an investment in our securities. Any of the described risks could significantly and negatively affect our business, financial condition, operating results and prices of our securities. The following risk factors describe the material risks that are presently known to us.

Risks Related to this Offering

Sales of our common stock by shareholders may have an adverse effect on the then prevailing market price of our common stock.

Sales of a substantial number of our common stock in the public market following this offering, including upon exercise of our currently outstanding Class A Warrants, Class B-1 Warrants, Class B-2 Warrants, Class C-1 Warrants and Class C-2 Warrants, could cause the market price of our common stock to decline and could impair our ability to raise capital through the sale of additional equity securities. We cannot predict the effect that future sales of our common stock or other equity-related securities would have on the market price of our common stock.

We have broad discretion in the use of the net proceeds from this offering and may use the net proceeds in ways with which you disagree.

Our management will have broad discretion in the application of the net proceeds from this offering and could spend the proceeds in ways that do not improve our results of operations or enhance the value of our securities. You will be relying on the judgment of our management with regard to the use of these net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the net proceeds are being used appropriately. The failure by our management to apply these funds effectively could result in financial losses that could have a material adverse effect on our business, cause the price of our securities to decline. Pending the application of these funds, we may invest the net proceeds from this offering in a manner that does not produce income or that loses value.

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USE OF PROCEEDS

We estimate that we would receive net proceeds of approximately $38,439 if all Class C-1 Warrants were exercised on a cash basis. We estimate that we would receive net proceeds of approximately $9,888,306 if all Class C-2 Warrants were exercised on a cash basis. It is possible that some or all of the Class C-1 Warrants and Class C-2 Warrants may expire and may never be exercised or may be exercised on a cashless basis.

We intend to use the net proceeds from the exercise of the warrants for capital expenditures, including the remainder of the purchase price for our recently acquired vessels and acquisitions of additional vessels which we have not yet identified, and for other general corporate purposes.

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CAPITALIZATION

The following table sets forth our consolidated capitalization at September 30, 2024:

Please refer to our Current Report on Form 6-K, filed with the SEC on November 19, 2024 which includes our interim condensed consolidated balance sheet and interim condensed statements of operations and cash flows as of and for the nine-month period ended September 30, 2024, which are incomplete as to notes, incorporated by reference herein.

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COMMON STOCK DIVIDEND POLICY

We currently intend to retain our future earnings, if any, to fund the development and growth of our business. Our board of directors will, however, evaluate our dividend policy consistent with our cash flows and liquidity requirements and we may consider paying dividends on our common stock depending on future performance of our business and financial condition. Declaration and payment of any future dividend is subject to the discretion of our Board of Directors. The timing and amount of dividend payments will be dependent upon our earnings, financial condition, cash requirements and availability, restrictions in our loan agreements, or other financing arrangements, the provisions of Marshall Islands law affecting the payment of distributions to stockholders and other factors, and will be subject to the priority of our Series A Convertible Preferred Stock, which, as described elsewhere in this prospectus, earn dividends at a dividend rate of 5.00% per annum per $25.00 of liquidation preference per share. Because we are a holding company with no material assets other than the stock of our subsidiaries, our ability to pay dividends will depend on the earnings and cash flow of our subsidiaries and their ability to pay dividends to us. Marshall Islands law generally prohibits the payment of dividends other than from surplus or while a company is insolvent or would be rendered insolvent upon the payment thereof.

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TAX CONSIDERATIONS

See “Item 10. Additional Information — E. Tax Considerations” in our Annual Report on Form 20-F for the year ended December 31, 2023 incorporated by reference herein.

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DESCRIPTION OF CAPITAL STOCK

See “Item 10. Additional Information — A. Share Capital” in our Annual Report on Form 20-F for the year ended December 31, 2023 incorporated by reference herein.

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PLAN OF DISTRIBUTION

We will deliver shares of our common stock upon exercise of the Class C-1 Warrants and Class C-2 Warrants. As of the date of this prospectus, the outstanding Class C-1 Warrants were exercisable for a total of 30,572 shares of common stock and the Class C-2 Warrants were exercisable for a total of 7,864,715 shares of common stock. For additional information about the Class C-1 Warrants and Class C-2 Warrants, see “Item 10. Additional Information — A. Share Capital” in our Annual Report on Form 20-F for the year ended December 31, 2023 incorporated by reference herein.

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SERVICE OF PROCESS AND ENFORCEMENT OF CIVIL LIABILITIES

We are a Marshall Islands corporation and our executive office is located outside of the United States in Athens, Greece. Our directors and officers and those of our subsidiaries are residents of countries other than the United States. Substantially all of our and our subsidiaries’ assets and a substantial portion of the assets of our directors and officers are located outside the United States. As a result, it may be difficult or impossible for United States investors to effect service of process within the United States upon us, our directors or officers, our subsidiaries or to realize against us or them judgments obtained in United States courts, including judgments predicated upon the civil liability provisions of the securities laws of the United States or any state in the United States.

In addition, there is uncertainty as to whether the courts of the Marshall Islands would (1) recognize or enforce against us, or our directors or officers judgments of courts of the United States based on civil liability provisions of applicable U.S. federal and state securities laws; or (2) impose liabilities against us or our directors and officers in original actions brought in the Marshall Islands, based on these laws.

You may also have difficulties enforcing in courts outside the United States judgments obtained in the U.S. courts against any of our directors and executive officers or us, including actions under the civil liability provisions of the U.S. securities laws.

LEGAL MATTERS

Certain legal matters with respect to Marshall Islands law have been passed upon for us by Reeder & Simpson P.C. Certain matters of U.S. Federal and New York law have been passed upon for us by Goodwin Procter LLP, New York, New York.

EXPERTS

The combined financial statements of C3is Inc. Predecessor for the period from March 12, 2021 (inception date) to December 31, 2021 and for the period from January 1, 2022 to October 18, 2022, incorporated by reference into this Prospectus by reference to C3is Inc.’s annual report on Form 20-F for the year ended December 31, 2023, have been audited by Deloitte Certified Public Accountants, S.A., an independent registered public accounting firm, as stated in their report. Such financial statements are incorporated by reference in reliance upon the report of such firm given their authority as experts in accounting and auditing.

The consolidated financial statements of C3is Inc. as of December 31, 2022 and 2023 and for the period from July 25 2022 (date of incorporation) to December 31, 2022 and for the year ended December 31, 2023, incorporated by reference into this Prospectus by reference to C3is Inc.’s annual report on Form 20-F for the year ended December 31, 2023, have been audited by Deloitte Certified Public Accountants, S.A., an independent registered public accounting firm, as stated in their report. Such financial statements are incorporated by reference in reliance upon the report of such firm given their authority as experts in accounting and auditing.

The office of Deloitte Certified Public Accountants, S.A. is located at Fragoklissias 3a & Granikou Street, Maroussi, Athens 151 25, Greece.

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OTHER EXPENSES OF ISSUANCE AND OFFERING

The expenses of the offering of the securities to which this prospectus relates were paid in connection with the initial offering of the Class C-1 Warrants and Class C-2 Warrants.

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Up to $9,926,745 of Common Shares

issuable upon the exercise of outstanding Class C-1 Warrants and Class C-2 Warrants

C3IS INC.

PROSPECTUS

    , 2024

PART II: INFORMATION NOT REQUIRED IN THE PROSPECTUS

Item 6. Indemnification of Directors and Officers

The bylaws of the Registrant provide that any person who is or was a director or officer of the Registrant, or is or was serving at the request of the Registrant as a director or officer of another, partnership, joint venture, trust or other enterprise, shall be entitled to be indemnified by the Registrant upon the same terms, under the same conditions, and to the same extent as authorized by Section 60 of the Marshall Islands Business Corporations Act (the “BCA”), if he acted in good faith and in a manner he reasonably believed to be in or not opposed to the best interests of the Registrant, and, with respect to any criminal action or proceeding, had no reasonable cause to believe his conduct was unlawful.

Section 60 of the BCA provides as follows:

Indemnification of directors and officers.

(1) Actions not by or in right of the corporation. A corporation shall have the power to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation) by reason of the fact that he is or was a director or officer of the corporation, or is or was serving at the request of the corporation as a director or officer of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by him in connection with such action, suit or proceeding if he acted in good faith and in a manner he reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe that his conduct was unlawful. The termination of any action, suit or proceeding by judgment, order, settlement, conviction, or upon a plea of no contest, or its equivalent, shall not, of itself, create a presumption that the person did not act in good faith and in a manner which he reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had reasonable cause to believe that his conduct was unlawful.

(2) Actions by or in right of the corporation. A corporation shall have power to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the corporation to procure judgment in its favor by reason of the fact that he is or was a director or officer of the corporation, or is or was serving at the request of the corporation as a director or officer of another corporation, partnership, joint venture, trust or other enterprise against expenses (including attorneys’ fees) actually and reasonably incurred by him or in connection with the defense or settlement of such action or suit if he acted in good faith and in a manner he reasonably believed to be in or not, opposed to the best interests of the corporation and except that no indemnification shall be made in respect of any claim, issue or matter as to which such person shall have been adjudged to be liable for negligence or misconduct in the performance of his duty to the corporation unless and only to the extent that the court in which such action or suit was brought shall determine upon application that, despite the adjudication of liability but in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the court shall deem proper.

(3) When director or officer successful. To the extent that a director or officer of a corporation has been successful on the merits or otherwise in defense of any action, suit or proceeding referred to in subsections (1) or (2) of this section, or in the defense of a claim, issue or matter therein, he shall be indemnified against expenses (including attorneys’ fees) actually and reasonably incurred by him in connection therewith.

(4) Payment of expenses in advance. Expenses incurred in defending a civil or criminal action, suit or proceeding may be paid in advance of the final disposition of such action, suit or proceeding as authorized by the

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board of directors in the specific case upon receipt of an undertaking by or on behalf of the director or officer to repay such amount if it shall ultimately be determined that he is not entitled to be indemnified by the corporation as authorized in this section.

(5) Indemnification pursuant to other rights. The indemnification and advancement of expenses provided by, or granted pursuant to, the other subsections of this section shall not be deemed exclusive of any other rights to which those seeking indemnification or advancement of expenses may be entitled under any bylaw, agreement, vote of stockholders or disinterested directors or otherwise, both as to action in his official capacity and as to action in another capacity while holding such office.

(6) Continuation of indemnification. The indemnification and advancement of expenses provided by, or granted pursuant to, this section shall, unless otherwise provided when authorized or ratified, continue as to a person who has ceased to be a director, officer, employee or agent and shall inure to the benefit of the heirs, executors and administrators of such a person.

(7) Insurance. A corporation shall have the power to purchase and maintain insurance on behalf of any person who is or was a director or officer of the corporation or is or was serving at the request of the corporation as a director or officer against any liability asserted against him and incurred by him in such capacity whether or not the corporation would have the power to indemnify him against such liability under the provisions of this section.

Item 7. Recent Sales of Unregistered Securities

The Company issued 31,826 shares of its common stock and 600,000 shares of its Series A Convertible Preferred Stock to Imperial Petroleum Inc. in exchange for its contribution to the Company of all the outstanding shares of the Company’s two vessel-owning subsidiaries in conjunction with the spin-off transaction completed on June 21, 2023. These issuances were each exempt from registration as a transaction not involving an offering in the United States under Regulation S of the Securities Act.

Item 8. Exhibits and Financial Statement Schedules

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Item 9. Undertakings

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Provided, however, that paragraphs (i), (ii) and (iii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the SEC by the registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form F-1 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Athens, Greece on the 10th day of December, 2024.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities indicated on December 10, 2024.

Authorized Representative

Pursuant to the requirements of the Securities Act of 1933, as amended, the undersigned, the duly authorized representative of the Registrant in the United States, has signed this registration statement on Form F-1 in the City of Newark, State of Delaware, on December 10, 2024.

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement No. 333-276868 on Form F-1 of our report dated April 12, 2023 relating to the combined financial statements of C3is Inc. Predecessor, appearing in the Annual Report on Form 20-F of C3is Inc. for the year ended December 31, 2023. We also consent to the reference to us under the heading “Experts” in such Registration Statement.

/s/ Deloitte Certified Public Accountants S.A.

Athens, Greece

December 10, 2024

Exhibit 23.2

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement No. 333-276868 on Form F-1 of our report dated April 30, 2024 relating to the consolidated financial statements of C3is Inc., appearing in the Annual Report on Form 20-F of C3is Inc. for the year ended December 31, 2023. We also consent to the reference to us under the heading “Experts” in such Registration Statement.

/s/ Deloitte Certified Public Accountants S.A.

Athens, Greece

December 10, 2024