Table of Contents ENPHASE ENERGY, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 16. STOCK-BASED COMPENSATION 2011 Plan Under the 2011 Equity Incentive Plan (the “2011 Plan”), the Company could initially issue up to 2,643,171 shares of its common stock pursuant to stock options, stock appreciation rights (“SARS”), restricted stock awards (“RSA”), RSUs, PSUs, and other forms of equity compensation, or collectively, stock awards, all of which may be granted to employees, including officers, and to non-employee directors and consultants. Options granted under the 2011 Plan before August 1, 2012 generally expire 10 years after the grant date and options granted thereafter generally expire seven years after the grant date. Equity awards granted under the 2011 Plan generally vest over a four year period from the date of grant based on continued employment. As of May 19, 2021, no further stock options or other stock awards may be granted under the 2011 Plan. 2021 Plan On May 19, 2021, at the 2021 annual meeting of stockholders of the Company, the stockholders approved the 2021 Equity Incentive Plan (the “2021 Plan”), as the successor to the 2011 Plan. The 2021 Plan provides for the grant of incentive stock options, SARS, RSAs, RSUs, PSUs other stock awards. Eligible participants under the 2021 Plan include Company’s employees, directors and consultants. The 2021 Plan provides, among other things, that the number of shares of the Company’s common stock, $0.00001 par value per share, reserved for issuance under the 2021 Plan (subject to adjustment for certain changes in the Company’s capitalization) is equal to: (A) the sum of (i) 9,100,456 newly reserved shares of the Company’s common stock and (ii) 5,256,517 Returning Shares (as defined below) as such shares become available from time to time as set forth in the 2021 Plan. “Returning Shares” means shares subject to any outstanding award granted under the 2011 Plan (“Prior Plan Award”) that are (i) not issued because such Prior Plan Award or any portion thereof expires or otherwise terminates without all of the shares covered by such Prior Plan Award having been issued, or is settled in cash; (ii) forfeited back to or repurchased by the Company because of a failure to vest; or (iii) reacquired or withheld (or not issued) by the Company to satisfy the purchase price of, or a tax withholding obligation in connection with, a Prior Plan Award that is a Full Value Award (as defined in the 2021 Plan). As a result of the approval of the 2021 Plan, no additional awards may be granted from the 2011 Plan. As of December 31, 2023, 6,059,212 shares remained available for issuance pursuant to future grants under the 2021 Plan. 2011 Employee Stock Purchase Plan The 2011 Employee Stock Purchase Plan (“ESPP”) became effective immediately upon the execution and delivery of the underwriting agreement for the Company’s initial public offering on March 29, 2012. The ESPP authorized the issuance of 669,603 shares of the Company’s common stock pursuant to purchase rights granted to employees. The number of shares of common stock reserved for issuance will automatically increase, on each January 1, by a lesser of (i) 700,000 shares of the Company’s common stock or (ii) 1.0% of the total number of shares of the Company’s common stock outstanding on December 31 of the preceding calendar year, as determined by the Company’s board of directors. In 2022, the Company’s board of directors voted to decline the automatic increase of 700,000 shares that were to be added on January 1, 2023 for issuance under the 2011 ESPP plan. As of December 31, 2023, 1,533,742 shares remained available for future issuance under the ESPP. On January 1, 2024, the shares available for issuance under the ESPP automatically increased by 700,000 shares. The ESPP is implemented by concurrent offering periods and each offering period may contain up to four interim purchase periods. In general, offering periods consist of the 24-month periods commencing on each May 15 and November 15 of a calendar year. Enphase Energy, Inc. | 2023 Form 10-K | 111