Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2025

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

4. Fair Value of Financial Instruments

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. In order to increase consistency and comparability of fair value measurements, financial instruments are categorized based on a hierarchy that prioritizes observable and unobservable inputs used to measure fair value into three broad levels, which are described below:

•Level 1 — Inputs are unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

•Level 2 — Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.) and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs).

•Level 3 — Unobservable inputs that reflect the Company’s estimates about the assumptions that market participants would use in pricing the asset or liability. The Company develops these inputs based on the best information available, including its own data.

The Company’s financial assets and liabilities that are measured at fair value on a recurring basis consist of money market funds, deferred compensation plan liabilities, contingent consideration liabilities and equity investments.

The Company invests excess cash from its operating cash accounts in overnight investments and reflects these amounts in cash and cash equivalents in the condensed consolidated balance sheets at fair value using quoted prices in active markets for identical assets.

The tables below present information about the Company’s assets and liabilities measured at fair value on a recurring basis:

			June 30, 2025
	Total Fair
(in thousands)	Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	533,320	$	533,320	$	—	$	—
Investment securities		44,235		44,235		—		—
Total assets	$	577,555	$	577,555	$	—	$	—
Liabilities:
Deferred compensation plan liabilities	$	777	$	777	$	—	$	—
Contingent consideration liabilities		43,042		—		—		43,042
Total liabilities	$	43,819	$	777	$	—	$	43,042
			December 31, 2024
	Total Fair
(in thousands)	Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	682,209	$	682,209	$	—	$	—
Investment securities		39,489		39,489		—		—
Total assets	$	721,698	$	721,698	$	—	$	—

Nonqualified Deferred Compensation Plan

The Company maintains the Lantheus Nonqualified Deferred Compensation Plan (the “LDCP”) for the benefit of certain key, highly-compensated employees and non-employee directors. The assets of the LDCP are currently invested in corporate-owned life insurance ("COLI") at June 30, 2025. There were no assets or liabilities balances in the LDCP at December 31, 2024. The liabilities of the LDCP are presented in other long-term liabilities in the Company’s condensed consolidated balance sheets. See Note 18, “Benefit Plans” for more information on the LDCP.

Perspective Therapeutics Inc. Equity Securities

At June 30, 2025, the Company held 11,677,339 shares of Perspective common stock (“Perspective Shares”). The Company accounts for its investment in Perspective Shares as an equity investment with a readily determinable fair value, as the securities are publicly traded on the New York Stock Exchange (“NYSE”). The fair value of the Perspective Shares is based on its closing price on the NYSE at the end of the fiscal period and is classified within Level 1 of the fair value hierarchy because the equity securities are valued using quoted market prices. The fair value of the Perspective Shares as of June 30, 2025 was approximately $40.2 million based on a closing market price of $3.44 per share on June 30, 2025, resulting in an unrealized gain of $15.3 million and $2.9 million for the three and six months ended June 30, 2025. See Note 19, “Acquisitions” for further discussion of the Perspective transaction.

Radiopharm Theranostics Limited Equity Securities

The Company held 149,625,180 shares of Radiopharm common stock (“Radiopharm Shares”) as of December 31, 2024. In January 2025, the Company purchased via private placement, an additional 133,333,333 Radiopharm Shares for $5.0 million. At June 30, 2025, the Company held 282,958,513 Radiopharm Shares. The Company accounts for its investment in Radiopharm Shares as an equity investment with a readily determinable fair value, as the securities are publicly traded on the Australian Stock Exchange (“ASX”). The fair value of the Radiopharm Shares is based on the closing price on the ASX at the end of the fiscal period and is classified within Level 1 of the fair value hierarchy because the equity securities are valued using quoted market prices. The fair value of the Radiopharm Shares as of June 30, 2025 was approximately $4.1 million based on the converted closing market price of approximately $0.01 per share on June 30, 2025, resulting in an unrealized loss on equity securities of $0.8 million and $3.3 million for the three and six months ended June 30, 2025. See Note 19, “Acquisitions” for further discussion of the Radiopharm transaction.

Contingent Consideration

Progenics

The Company assumed contingent consideration liabilities related to a previous acquisition completed by Progenics in 2013 (“2013 Acquisition”). These contingent consideration liabilities include potential payments of up to $70.0 million if the Company attains certain net

sales targets primarily for AZEDRA and 1095 (also known as 131 I-MIP-1095) and a $5.0 million 1095 commercialization milestone. Additionally, there is a potential payment of up to $10.0 million for a commercialization milestone related to a prostate cancer product candidate the Company refers to as “1404” that was out-licensed to ROTOP Pharmaka GmbH. The Company’s total potential payments related to the 2013 Acquisition are approximately $85.0 million. The Company considers the contingent consideration liabilities relating to the 2013 Acquisition each a Level 3 instrument (one with significant unobservable inputs) in the fair value hierarchy. The estimated fair value of these was determined based on probability adjusted discounted cash flows and Monte Carlo simulation models that included significant estimates and assumptions pertaining to commercialization events and sales targets. The most significant unobservable inputs with respect to 1095 and 1404 are the probabilities of achieving regulatory approval of those development projects and subsequent commercial success.

Significant changes in any of the probabilities of success, the probabilities as to the periods in which sales targets and milestones will be achieved, discount rates or underlying revenue forecasts would result in a higher fair value measurement. The Company records the contingent consideration liabilities at fair value with changes in estimated fair values recorded in general and administrative expenses in the condensed consolidated statements of operations. The Company can give no assurance that the actual amounts paid, if any, in connection with the contingent consideration liabilities, will be consistent with any recurring fair value estimate of such contingent consideration liabilities. The Company estimated that the probability of successfully meeting the sales targets and commercialization milestones described above was zero. As a result of this assessment, the Company determined the value of the contingent consideration liabilities to be $0 at June 30, 2025 and December 31, 2024.

Evergreen Theragnostics, Inc.

Pursuant to the terms of the Agreement and Plan of Merger (the "Evergreen Merger Agreement") with Evergreen and Shareholder Representative Services LLC governing the Company's acquisition of Evergreen in April 2025 (see Note 19, "Acquisitions"), the Company is required to make certain remaining payments of up to $727.5 million in cash upon the achievement of specified milestones in connection with the development and commercialization of certain milestone products, as defined in the Evergreen Merger Agreement, and Octevy (also referred to as LNTH-2501), a registrational-stage positron emission tomography ("PET") diagnostic imaging agent targeting neuroendocrine tumors. The Company records these possible payments as contingent consideration liabilities that are classified within Level 3 of the fair value hierarchy. The Company estimated the fair value of the contingent consideration liabilities associated with the sales milestones using a Monte Carlo simulation in a risk-neutral framework, whereby the achievement of the future revenue associated with the sales milestones was simulated using a geometric Brownian motion model. The Company estimated the fair value of the contingent consideration liability associated with the development and commercialization milestones using a probability-weighted discounted cash flow (“DCF”) approach.

Significant changes in any of the probabilities of success, the probabilities as to the periods in which sales targets and milestones will be achieved, discount rates or underlying revenue forecasts would result in a higher or lower fair value measurement. The Company records the contingent consideration liabilities at fair value with changes in estimated fair values recorded in general and administrative expenses in the condensed consolidated statements of operations. The Company can give no assurance that the actual amounts paid, if any, in connection with the contingent consideration liabilities, will be consistent with any recurring fair value estimate of such contingent consideration liabilities. As a result of this assessment, the Company determined the value of the contingent consideration liabilities to be $43.0 million at June 30, 2025.

The recurring Level 3 fair value measurements of the Company's contingent consideration liabilities include the following significant unobservable inputs (in thousands, except percent data):

	Fair Value at
Contingent Consideration Liability	June 30, 2025		Valuation Technique	Unobservable Inputs	Range	Weighted Average
Development and commercialization milestones		39,888	Discounted cash flow	Payment discount rate	7.8% - 12.1%	7.9%
				Probability of payment	0% - 100%	23.4%
				Range of expected payment dates	2026 - 2037	N/A
Sales milestone		3,154	Scenario analysis	Revenue volatility	37.5%	37.5%
				Revenue discount rate	9.1% - 9.4%	N/A
				Payment discount rate	7.9% - 9.2%	N/A
Total contingent consideration liabilities	$	43,042