Table of Contents ENPHASE ENERGY, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS The following table presents assets and liabilities measured at fair value on a recurring basis using the above input categories: December 31, 2023 December 31, 2022 (In thousands) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Assets: Cash and cash equivalents: Money market funds $ 132,037 $ — $ — $ 165,407 $ — $ — Certificates of deposit — 750 — — — — Commercial paper — 1,694 — — 50,764 — Corporate notes and bonds — 462 — — — — U.S. Treasuries — — — — 4,094 — Marketable securities: Certificates of deposit — 55,162 — — 31,757 — Commercial paper — 69,743 — — 97,907 — Corporate notes and bonds — 405,634 — — 165,576 — U.S. Treasuries — 327,891 — — 297,131 — U.S. Government agency securities — 547,856 — — 547,228 — Other assets Investments in debt securities — — 79,855 — — 56,777 Total assets measured at fair value $ 132,037 $ 1,409,192 $ 79,855 $ 165,407 $ 1,194,457 $ 56,777 Liabilities: Warranty obligations Current $ — $ — $ 28,667 $ — $ — $ 30,740 Non-current — — 133,126 — — 75,749 Total warranty obligations measured at fair value — — 161,793 — — 106,489 Total liabilities measured at fair value $ — $ — $ 161,793 $ — $ — $ 106,489 Notes due 2028, Notes due 2026 and Notes due 2025 The Company carries the Notes due 2028 and Notes due 2026 at face value less unamortized debt issuance costs on its consolidated balance sheets. The Company carries the Notes due 2025 at face value less unamortized debt discount and issuance costs on its consolidated balance sheets. As of December 31, 2023, the fair value of the Notes due 2028, Notes due 2026 and Notes due 2025 was $511.8 million, $568.8 million and $147.7 million, respectively. The fair value as of December 31, 2023 was determined based on the closing trading price per $100 principal amount as of the last day of trading for the period. The Company considers the fair value of the Notes due 2028, Notes due 2026 and Notes due 2025 to be a Level 2 measurement as they are not actively traded. Investments in debt securities In January 2021, the Company invested approximately $25.0 million in a privately-held company. The Company concluded the investment qualifies as an investment in a debt security, as it accrues interest and principal plus accrued interest becomes payable back to the Company at certain dates unless it is converted to equity at a pre-determined price. As the investment includes a conversion option, the Company has elected to account for this investment under the fair value option and any change in fair value of the investment is recognized in “Other income (expense), net” in the Company’s consolidated statement of operations for that period. Further, the Company has concluded that the Company’s investment in a debt security is considered to be a Level 3 measurement due to the use of significant unobservable inputs in the valuation model. The fair value was determined using discounted cash flow methodology and assumptions include implied yield and change in estimated term of investment being held-to- maturity. Enphase Energy, Inc. | 2023 Form 10-K | 97