3. Restricted Marketable Securities (Notes)

3. Restricted Marketable Securities

Restricted marketable securities consisted of the following as of September 30, 2026 and December 31, 2025 (in thousands):


	September 30, 2026		December 31, 2025
U.S. debt	$	107,130	$	115,350
Foreign government obligations	50,490		54,156
Supranational debt	27,318		28,276
U.S. government obligations	17,559		19,390
Total restricted marketable securities	$	202,497	$	217,172

Our restricted marketable securities represent long-term investments to fund the estimated future cost of collecting and recycling modules covered under our solar module collection and recycling program. We have established a trust under which funds are put into custodial accounts with an established and reputable bank, for which First Solar, Inc.; First Solar Malaysia Sdn. Bhd.; and First Solar Holdings GmbH are grantors. As of September 30, 2026 and December 31, 2025, such custodial accounts also included noncurrent restricted cash and cash equivalents balances of $13.3 million and $6.9 million, respectively, which were reported within “Other assets.” Trust funds may be disbursed for qualified module collection and recycling costs (including capital and facility related recycling costs), payments to customers for assuming collection and recycling obligations, and reimbursements of any overfunded amounts. Investments in the trust must meet certain investment quality criteria comparable to highly rated government or agency bonds. As necessary, we fund any incremental amounts for our estimated collection and recycling obligations on an annual basis based on the estimated costs of collecting and recycling covered modules, estimated rates of return on our restricted marketable securities, and an estimated solar module life of 25 years, less amounts already funded in prior years. During the nine months ended September 30, 2026 and 2025, we purchased no restricted securities and $5.0 million of restricted securities, respectively, as part of our ongoing management of the custodial accounts.

See Note 8. “Fair Value Measurements” to our condensed consolidated financial statements for information about the fair value of our restricted marketable securities.

The following tables summarize the unrealized gains and losses related to our restricted marketable securities, by major security type, as of September 30, 2026 and December 31, 2025 (in thousands):


	As of September 30, 2026
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. debt	$	141,374	$	—	$	34,244	$	107,130
Foreign government obligations	65,431		—		14,941		50,490
Supranational debt	29,957		72		2,711		27,318
U.S. government obligations	24,202		—		6,643		17,559
Total	$	260,964	$	72	$	58,539	$	202,497


	As of December 31, 2025
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. debt	$	142,790	$	—	$	27,440	$	115,350
Foreign government obligations	67,091		—		12,935		54,156
Supranational debt	30,123		59		1,906		28,276
U.S. government obligations	24,274		—		4,884		19,390
Total	$	264,278	$	59	$	47,165	$	217,172

As of September 30, 2026, the contractual maturities of these securities were between 4 years and 13 years, and restricted marketable securities with unrealized losses had generally been in a loss position for a period of time greater than 12 months. The unrealized losses were primarily due to increases in interest rates relative to rates at the time of purchase, and, based on the underlying credit quality of the investments, we expect to hold such securities until we recover our cost basis.