
	December 31, 2025
(in millions)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. treasury securities	$	1,222	$	3	$	—	$	1,224
U.S. government agencies securities	15		—		—		15
Corporate debt securities	1,392		7		—		1,398
Residential mortgage and asset-backed securities	405		2		—		407
Total	$	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 $724 million that have been in a continuous unrealized loss position for less than 12 months as of December 31, 2025. No allowance for credit losses was recognized for investments with unrealized losses as of December 31, 2025 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.


	December 31, 2025
(in millions)	Amortized Cost		Fair Value
Within one year	$	70	$	70
After one year through five years	2,931		2,941
After five years through ten years	32		32
Total	$	3,033	$	3,044

The following table summarizes the classification of our equity securities on our 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)	December 31, 2025		December 31, 2024
Equity securities measured at fair value:
Cash and cash equivalents:
Money market funds	$	6,150	$	8,502
Prepaid and other current assets:
Equity method investment in Galapagos NV (“Galapagos”) – fair value option	551		462
Equity method investment in Arcus Biosciences, Inc. (“Arcus”) – fair value option	749		448
Other equity method investments – fair value option(1)	183		53
Other	499		614
Other long-term assets	386		327
Equity method investments and other equity securities without readily determinable fair values:
Other long-term assets(2)	393		386
Total	$	8,909	$	10,791

(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 Consolidated Statements of Operations:


	Year Ended December 31,
(in millions)	2025		2024		2023
Unrealized (gain) loss, net, related to fair value option investments	$	(440)	$	377	$	68
Unrealized loss (gain), net, related to all other equity investments	35		(93)		(8)
Total unrealized (gain) loss, net	$	(404)	$	284	$	60

In 2025, we donated certain equity securities at fair value 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 $89 million in Selling, general and administrative expenses on our Consolidated Statements of Operations.