Appendix Enphase Energy, Inc. reconciliation of GAAP nancial measures to non-GAAP nancial measures Enphase Energy, Inc. reconciliation of GAAP nancial measures to non-GAAP nancial measures (continued) In thousands, except per share data and percentages Year ended In thousands, except per share data and percentages Year ended 2023 2022 2018 2023 2022 2018 Gross prot (GAAP) $ 1,058,388 $ 974,595 $ 94,445 Net income (loss) per share, basic (GAAP) $ 3.22 $ 2.94 $ (0.12) Stock-based compensation 13,357 13,097 1,071 Stock-based compensation 1.56 1.60 0.11 Acquisition related amortization 7,580 6,324 - Acquisition related expenses and amortization 0.17 0.17 0.02 Gross prot (Non-GAAP) $ 1,079,325 $ 994,016 $ 95,516 Restructuring and asset impairment charges 0.12 0.02 0.04 Reserve for non-recurring legal matter - - 0.02 Gross margin (GAAP) 46.2 % 41.8 % 29.9 % Non-cash interest expense 0.06 0.06 0.03 Stock-based compensation 0.6 % 0.5 % 0.3 % Non-GAAP income tax adjustment (0.63) (0.01) - Acquisition related amortization 0.3 % 0.3 % - % Net income per share, basic (Non-GAAP) $ 4.50 $ 4.78 $ 0.10 Gross margin (Non-GAAP) 47.1 % 42.6 % 30.2 % Shares used in per share calculation, basic and 136,376 135,349 99,619 Operating expenses (GAAP) $ 612,647 $ 526,334 $ 92,849 diluted (GAAP and Non-GAAP) Stock-based compensation (199,500) (203,705) (10,361) Net income (loss) per share, diluted (GAAP) $ 3.08 $ 2.77 $ (0.12) Acquisition related expenses and amortization (15,317) (16,521) (1,614) Stock-based compensation 1.57 1.55 0.11 Restructuring and asset impairment charges (15,715) (2,384) (4,128) Acquisition related expenses and amortization 0.16 0.16 0.02 Reserve for non-recurring legal matter - - (1,765) Restructuring, asset impairment and other charges 0.11 0.02 0.04 Operating expenses (Non-GAAP) $ 382,115 $ 303,724 $ 74,981 Reserve for non-recurring legal matter - - 0.02 Operating expense % of revenue 16.7 % 13.0 % 23.7 % Non-cash interest expense 0.06 0.06 0.03 Income from operations (GAAP) $ 445,741 $ 448,261 $ 1,596 Non-GAAP income tax adjustment (0.57) 0.06 - 1 $ 4.41 $ 4.62 $ 0.10 Stock-based compensation 212,857 216,802 11,432 Net income per share, diluted (Non-GAAP) Acquisition related expenses and amortization 22,897 22,845 1,614 Shares used in per share calculation (GAAP) 143,290 144,390 99,619 Restructuring and asset impairment charges 15,715 2,384 4,128 Shares used in per share calculation (Non-GAAP) 139,214 140,315 111,696 Reserve for non-recurring legal matter - - 1,765 Income from operations (Non-GAAP) $ 697,210 $ 690,292 $ 20,535 Income-based government grants (GAAP) $ 53,470 $ - $ - Net income (loss) (GAAP) $ 438,936 $ 397,362 $ (11,627) Incremental cost for manufacturing in U.S. (11,603) - - Stock-based compensation 212,857 216,802 11,432 Net IRA benet (Non-GAAP) $ 41,867 $ - $ - Acquisition related expenses and amortization 22,897 22,845 1,614 Net cash provided by operating activities (GAAP) $ 696,780 $ 744,817 $ 16,132 Restructuring and asset impairment charges 15,715 2,384 4,128 Purchases of property and equipment (110,401) (46,443) (4,151) Reserve for non-recurring legal matter - - 1,765 Free cash ow (Non-GAAP) $ 586,379 $ 698,374 $ 11,981 Non-cash interest expense 8,380 8,169 2,701 Non-GAAP income tax adjustment (85,544) (138) - Net income (Non-GAAP) $ 613,241 $ 647,424 $ 10,013 1 Calculation of non-GAAP diluted net income per share for the year ended December 31, 2023, 2022, and 2018, excludes convertible notes due 2023 expense, net of tax of approximately $0.1 million, $0.1 million, and $0.7 million, respectively, from non-GAAP net income. 42 ENPHASE CEO LETTER TO SHAREHOLDERS 2023 43