MAXY Maxygen, Inc. (MM)

EXPLANATORY NOTE

As contemplated by the Plan of Complete Liquidation and Dissolution of Maxygen, Inc. (the “Company”), the Company filed a certificate of dissolution with the Secretary of State of the State of Delaware, which became effective on August 29, 2013 and provides for the dissolution of the Company under the General Corporation Law of the State of Delaware (the “Dissolution”). In connection with the Dissolution, all outstanding equity awards granted under or governed by the Company’s equity incentive plans (collectively, the “Plans”), including the Company’s 2006 Equity Incentive Plan (the “2006 Plan”) and the Company’s 1999 Employee Stock Purchase Plan (“ESPP”), have been cancelled and each of the Plans has been terminated.

In accordance with the undertaking in the Registration Statements (as defined below), the Company is hereby filing this Post-Effective Amendment No. 1 to each of the Company’s registration statements on Form S-8 (registration nos. 333-157928, 333-149622 and 333-138898); Post-Effective Amendment No. 2 to each of the Company’s registration statements on Form S-8 (registration nos. 333-141287, 333-57486, 333-44794, 333-38078 and 333-93423) and Post-Effective Amendment No. 3 to each of the Company’s registration statements on Form S-8 (registration nos. 333-132478, 333-123323, 333-113651, 333-104108 and 333-84904) (collectively, the “Registration Statements”) to terminate the effectiveness of each such Registration Statement and to remove from registration all shares of the Company’s common stock that have not been issued and are not subject to issuance pursuant to outstanding equity awards under the Plans, including 9,013,115 shares of the Company’s common stock that have not been issued and are not subject to issuance pursuant to outstanding equity awards under the 2006 Plan and 1,446,179 shares of the Company’s common stock that have not been issued and are not subject to issuance pursuant to the ESPP.