Fair Value Measurements

12 Months Ended

Dec. 31, 2025

Fair Value Disclosures [Abstract]

Fair Value Measurements

Note 8: Fair Value Measurements

The tables below present information about our assets and liabilities that are regularly measured and carried at fair value and indicate the level within the fair value hierarchy of the valuation techniques we utilized to determine such fair value:

	Fair Value Measurements on a Recurring Basis
	As of December 31, 2025
(In millions)	Total		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	2,233.2	$	—	$	2,233.2	$	—
Marketable debt securities:
Corporate debt securities	537.6		—		537.6		—
Government securities	648.8		—		648.8		—
Mortgage and other asset backed securities	52.7		—		52.7		—
Marketable equity securities	118.1		118.1		—		—
Other current assets:
Derivative contracts	10.0		—		10.0		—
Other non-current assets:
Convertible notes(1)	35.0		—		—		35.0
Plan assets for deferred compensation	52.2		—		52.2		—
Derivative contracts	0.4		—		0.4		—
Total	$	3,688.0	$	118.1	$	3,534.9	$	35.0
Liabilities:
Other current liabilities:
Derivative contracts	$	56.7	$	—	$	56.7	$	—
Other non-current liabilities:
Derivative contracts	2.2		—		2.2		—
Contingent consideration obligations	246.4		—		—		246.4
Total	$	305.3	$	—	$	58.9	$	246.4

(1) Convertible notes includes a $30.0 million convertible note we invested in as part of our strategic research arrangement with City Therapeutics during 2025, as well as a $5.0 million convertible note we invested into Neela Therapeutics, Inc. during 2025. We elected the fair value option for both convertible notes. For additional information on the arrangement with City Therapeutics, please read Note 19, Collaborative and Other Relationships, to these consolidated financial statements.

	Fair Value Measurements on a Recurring Basis
	As of December 31, 2024
(In millions)	Total		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	1,664.9	$	—	$	1,664.9	$	—
Marketable equity securities	179.7		179.7		—		—
Other current assets:
Derivative contracts	62.5		—		62.5		—
Other non-current assets:
Plan assets for deferred compensation	42.8		—		42.8		—
Total	$	1,949.9	$	179.7	$	1,770.2	$	—
Liabilities:
Other current liabilities:
Derivative contracts	$	11.7	$	—	$	11.7	$	—
Contingent consideration obligations	291.2		—		—		291.2
Other non-current liabilities:
Contingent consideration obligations	221.6		—		—		221.6
Total	$	524.5	$	—	$	11.7	$	512.8

Our marketable equity securities represent investments in publicly traded equity securities. Our ability to liquidate our investments in Denali may be limited by the size of our interest, the volume of market-related activity, our concentrated level of ownership and potential restrictions resulting from our status as a collaborator. Therefore, we may realize significantly less than the current value of such investments. For additional information on our investments in Denali common stock, please read Note 9, Financial Instruments, and Note 18, Other Consolidated Financial Statement Detail, to these consolidated financial statements.

There have been no material impairments of our assets measured and carried at fair value as of December 31, 2025 and 2024. In addition, there have been no changes to our valuation techniques as of December 31, 2025 and 2024.

For a description of our validation procedures related to prices provided by third-party pricing services and our option pricing valuation model, please read Note 1, Summary of Significant Accounting Policies - Fair Value Measurements, to these consolidated financial statements.

Level 3 Assets and Liabilities Held at Fair Value

The following tables present quantitative information, as of the dates indicated, about the valuation techniques and significant unobservable inputs used in the valuation of our Level 3 financial assets and liabilities measured at fair value on a recurring basis:

	Quantitative Information about Level 3 Fair Value Measurements
	As of December 31, 2025
(In millions)	Fair Value		Valuation Technique	Significant Unobservable Input(s)	Range	Weighted Average
Liabilities:
Contingent consideration obligations	$	246.4	Discounted cash flow	Discount rate	5.3% - 5.4%	5.4%
				Expected timing of achievement of development milestones	2028 - 2030	—

	Quantitative Information about Level 3 Fair Value Measurements
	As of December 31, 2024
(In millions)	Fair Value		Valuation Technique	Significant Unobservable Input(s)	Range	Weighted Average
Liabilities:
Contingent consideration obligations	$	512.8	Discounted cash flow	Discount rate	6.2% - 6.3%	6.2%
				Expected timing of achievement of development milestones	2025 - 2030	—

The weighted average discount rates were calculated based on the relative fair values of each distinct contingent consideration obligation related to our acquisition of HI-Bio in July 2024. In addition, we apply various probabilities of technological and regulatory success to the valuation models to estimate the fair values of these contingent consideration obligations, which ranged from approximately 70.0% to 95.0% as of December 31, 2025.

There were no transfers of assets or liabilities into or out of Level 3 as of December 31, 2025 and 2024.

Contingent Consideration Obligations

In connection with our acquisition of HI-Bio in July 2024 we agreed to make additional payments based upon the achievement of certain milestone events. The following table provides a roll forward of the fair value of our contingent consideration obligations, which were classified as Level 3 measurements:

	As of December 31,
(In millions)	2025		2024
Fair value, beginning of year	$	512.8	$	—
Contingent consideration resulting from HI-Bio acquisition	—		485.1
Changes in fair value	33.6		27.7
Payments	(300.0)		—
Fair value, end of year	$	246.4	$	512.8

Changes in the fair values of our contingent consideration obligations, other than changes due to payments, are recognized as a (gain) loss on fair value remeasurement of contingent consideration within our consolidated statements of income. The fair values of the contingent consideration liabilities were based on a probability-adjusted discounted cash flow calculation using Level 3 fair value measurements and inputs. For additional information on the valuation techniques and inputs utilized in the valuation of our financial assets and liabilities, please read Note 1, Summary of Significant Accounting Policies, to these consolidated financial statements.

As of December 31, 2025, the total remaining fair value of our contingent consideration obligations of $246.4 million was classified as long-term and reflected as a component of other long-term liabilities within our consolidated balance sheets.

As of December 31, 2024, approximately $291.2 million of the fair value of our total contingent consideration obligations was classified as short-term and reflected as a component of accrued expense and other with the remaining $221.6 million reflected as a component of other long-term liabilities within our consolidated balance sheets.

For the year ended December 31, 2025, changes in the fair value of our contingent consideration obligations were primarily due to changes in interest rates used to revalue our contingent consideration liabilities and the passage of time. For the year ended December 31, 2024, changes in the fair value of our contingent consideration obligations were primarily due to changes in interest rates used to revalue our contingent consideration liabilities, the passage of time and updates to the expected timing of achieving certain milestones which will trigger contingent consideration payments.

During the second quarter of 2025 the first milestone related to the fourth patient dosed in a Phase 3 clinical trial of felzartamab for AMR was achieved, resulting in a $150.0 million milestone payment made to the former shareholders of HI-Bio, which was paid during the third quarter of 2025. In October 2025 the second milestone related to the fourth patient dosed in a Phase 3 clinical trial of felzartamab for IgAN was achieved, resulting in a

$150.0 million milestone payment made to the former shareholders of HI-Bio, which was paid during the fourth quarter of 2025.

Financial Instruments Not Carried at Fair Value

Other Financial Instruments

Due to the short-term nature of certain financial instruments, the carrying value reflected in our consolidated balance sheets for current accounts receivable, due from anti-CD20 therapeutic programs, other current assets, accounts payable and accrued expense and other, approximates fair value.

Debt Instruments

The fair values of our debt instruments, which are Level 2 liabilities, are summarized as follows:

	Fair Value As of December 31,
(In millions)	2025		2024
Current portion:
4.050% Senior Notes due September 15, 2025(1)	$	—	$	1,741.0
Current portion of notes payable	—		1,741.0
Non-current portion:
2.250% Senior Notes due May 1, 2030	1,378.7		1,295.6
5.050% Senior Notes due January 15, 2031(1)	413.0		—
5.750% Senior Notes due May 15, 2035(1)	684.5		—
5.200% Senior Notes due September 15, 2045	1,029.5		1,008.0
3.150% Senior Notes due May 1, 2050	973.0		943.7
3.250% Senior Notes due February 15, 2051	461.8		448.9
6.450% Senior Notes due May 15, 2055(1)	737.6		—
Non-current portion of notes payable	5,678.1		3,696.2
Total notes payable	$	5,678.1	$	5,437.2

(1) In May 2025 we issued our 2025 Senior Notes for an aggregate principal amount of $1.75 billion. In June 2025 we used the net proceeds from the sale of our 2025 Senior Notes to redeem in full our 4.050% Senior Notes due September 15, 2025, prior to maturity. For additional information, please read Note 13, Indebtedness, to these consolidated financial statements.

The fair values of each of our series of Senior Notes were determined through market, observable and corroborated sources. The changes in the fair values of our Senior Notes as of December 31, 2025, compared to 2024, are primarily related to decreases in credit spreads used to value our Senior Notes since December 31, 2024. For additional information related to our Senior Notes, please read Note 13, Indebtedness, to these consolidated financial statements.