
	June 30, 2023								December 31, 2022
(in millions)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. treasury securities	$	378	$	—	$	(3)	$	375	$	415	$	—	$	(5)	$	410
U.S. government agencies securities	162		—		(1)		161		36		—		—		35
Non-U.S. government securities	16		—		—		15		34		—		—		34
Certificates of deposit	104		—		—		104		54		—		—		54
Corporate debt securities	1,358		—		(20)		1,338		1,452		—		(26)		1,427
Residential mortgage and asset-backed securities	348		—		(2)		346		335		—		(3)		333
Total	$	2,367	$	—	$	(26)	$	2,341	$	2,325	$	1	$	(34)	$	2,293

The following table summarizes information related to available-for-sale debt securities that have been in a continuous unrealized loss position, classified by length of time:


	June 30, 2023
	Less Than 12 Months				12 Months or Longer				Total
(in millions)	Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value
U.S. treasury securities	$	(2)	$	299	$	(1)	$	46	$	(3)	$	345
U.S. government agencies securities	(1)		149		—		—		(1)		149
Non-U.S. government securities	—		11		—		5		—		15
Corporate debt securities	(6)		522		(14)		647		(20)		1,168
Residential mortgage and asset-backed securities	(1)		266		—		42		(2)		308
Total	$	(10)	$	1,246	$	(16)	$	739	$	(26)	$	1,985


	December 31, 2022
	Less Than 12 Months				12 Months or Longer				Total
(in millions)	Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value
U.S. treasury securities	$	(2)	$	174	$	(3)	$	206	$	(5)	$	379
U.S. government agencies securities	—		21		—		—		—		21
Non-U.S. government securities	—		31		—		3		—		34
Corporate debt securities	(17)		774		(8)		439		(26)		1,213
Residential mortgage and asset-backed securities	(2)		205		(1)		56		(3)		261
Total	$	(22)	$	1,204	$	(12)	$	705	$	(34)	$	1,908

No allowance for credit losses was recognized for investments with unrealized losses as of June 30, 2023 as the unrealized losses were primarily driven by broader change in interest rates with no adverse conditions identified that would prevent the issuer from making scheduled principal and interest payments. We do not currently intend to sell, and it is not more likely than not that we will be required to sell, such investments before recovery of their amortized cost bases.

The following table summarizes the classification of our available-for-sale debt securities in our Condensed Consolidated Balance Sheets:


(in millions)	June 30, 2023		December 31, 2022
Cash and cash equivalents	$	44	$	75
Short-term marketable debt securities	963		973
Long-term marketable debt securities	1,334		1,245
Total	$	2,341	$	2,293


	June 30, 2023
(in millions)	Amortized Cost		Fair Value
Within one year	$	1,014	$	1,007
After one year through five years	1,332		1,313
After five years through ten years	17		16
After ten years	4		4
Total	$	2,367	$	2,341

The following table summarizes the classification of our equity securities measured at fair value on a recurring basis, on our Condensed Consolidated Balance Sheets:


(in millions)	June 30, 2023		December 31, 2022
Cash and cash equivalents	$	4,253	$	3,831
Prepaid and other current assets(1)	431		473
Other long-term assets(1)	1,046		943
Total	$	5,730	$	5,248

________________________________

(1) Prepaid and other current assets and Other long-term assets include our equity method investments in Arcus and Galapagos, respectively, for which we elected and applied the fair value option as we believe it best reflects the underlying economics of these investments. Our investment in Galapagos is classified in Other long-term assets due to certain lock-up provisions in our amended subscription agreement with them, which extend to August 2024.

Equity method investments and other equity investments without readily determinable fair values were $366 million and $423 million as of June 30, 2023 and December 31, 2022, respectively, and were excluded from the table above. These amounts were included in Other long-term assets on our Condensed Consolidated Balance Sheets.

We recognized $69 million net unrealized gains and $187 million net unrealized losses on equity securities for the three and six months ended June 30, 2023, respectively, and $303 million and $399 million net unrealized losses on equity securities for the three and six months ended June 30, 2022, respectively, which were included in Other income (expense), net on our Condensed Consolidated Statements of Income.

During the three months ended June 30, 2022, Gilead donated certain equity securities at fair value to the Gilead Foundation, a California nonprofit public benefit corporation (the “Foundation”). The Foundation is a related party as certain of our officers also serve as directors of the Foundation. The donation expense of $85 million was recorded within Selling, general and administrative expenses on our Condensed Consolidated Statements of Income during the three months ended June 30, 2022.