
	March 31, 2026								December 31, 2025
(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	$	300	$	—	$	(1)	$	298	$	1,222	$	3	$	—	$	1,224
U.S. government agencies securities	—		—		—		—		15		—		—		15
Corporate debt securities	557		—		(2)		555		1,392		7		—		1,398
Residential mortgage and asset-backed securities	144		—		—		144		405		2		—		407
Total	$	1,000	$	1	$	(4)	$	997	$	3,033	$	11	$	(1)	$	3,044

The total gross unrealized losses in the table above relate to available-for-sale debt securities, primarily corporate debt securities and U.S. treasury securities, with an estimated fair value of approximately $669 million and $724 million that have been in a continuous unrealized loss position for less than 12 months as of March 31, 2026 and December 31, 2025, respectively. No allowance for credit losses was recognized for investments with unrealized losses as of March 31, 2026 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. In April 2026, we sold all remaining securities.


	March 31, 2026
(in millions)	Amortized Cost		Fair Value
Within one year	$	15	$	15
After one year through five years	982		979
After five years through ten years	4		4
Total	$	1,000	$	997

The following table summarizes the classification of our equity securities on our Condensed Consolidated Balance Sheets, including certain equity method investments for which we elected and applied the fair value option as we believe it best reflects the underlying economics of these investments:


(in millions)	March 31, 2026		December 31, 2025
Equity securities measured at fair value:
Cash and cash equivalents:
Money market funds	$	5,966	$	6,150
Prepaid and other current assets:
Equity method investment in Galapagos NV (“Galapagos”) – fair value option	504		551
Equity method investment in Arcus Biosciences, Inc. – fair value option	679		749
Other equity method investments – fair value option(1)	155		183
Other	836		499
Other long-term assets	379		386
Equity method investments and other equity securities without readily determinable fair values:
Other long-term assets(2)	308		393
Total	$	8,827	$	8,909

(1) Mostly comprised of our equity interest in Assembly Biosciences, Inc. (“Assembly”), which was approximately 29% of outstanding Assembly stock at the time of our latest purchase of shares.

(2) Mostly comprised of equity interests in certain collaboration partners and investment funds that are considered to be variable interest entities (“VIEs”) for which we are not the primary beneficiary. Our maximum exposure to loss as a result of our involvement in these VIEs is limited to the value of our investment.

The following table summarizes net unrealized gains and losses related to equity securities still held as of the respective ending balance sheet dates for the periods below, included in Other (income) expense, net on our Condensed Consolidated Statements of Operations:


	Three Months Ended
	March 31,
(in millions)	2026		2025
Unrealized loss, net, related to fair value option investments	$	146	$	276
Unrealized (gain) loss, net, related to all other equity investments	(277)		160
Total unrealized (gain) loss, net	$	(131)	$	436

During the three months ended March 31, 2026, we donated certain equity securities to the Gilead Foundation, a California nonprofit public benefit corporation for which certain of our officers serve as directors, and recorded a related expense of $63 million in Selling, general and administrative expenses on our Condensed Consolidated Statements of Operations.