Fair Value of Financial Instruments

3 Months Ended

Mar. 31, 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 a 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 assets (which currently consist of mutual funds) and deferred compensation plan 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. Investment in equity securities resulting from the Perspective Therapeutics, Inc. (“Perspective”) and Radiopharm Theranostics Limited (“Radiopharm”) strategic agreements are recorded at fair value and adjusted for price changes observable in the market each quarter.

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

	March 31, 2025
(in thousands)	Total Fair Value		Level 1		Level 2
Assets:
Money market funds	$	489,966	$	489,966	$	—
Mutual funds	684		684		—
Investment securities	29,691		29,691		—
Total assets	$	520,341	$	520,341	$	—
Liabilities:
Deferred compensation plan liabilities	$	621	$	—	$	621
Total liabilities	$	621	$	—	$	621

    

	December 31, 2024
(in thousands)	Total Fair Value		Level 1		Level 2
Assets:
Money market funds	$	682,209	$	682,209	$	—
Investment securities	39,489		39,489		—
Total assets	$	721,698	$	721,698	$	—

During the three months ended March 31, 2025, there were no transfers into or out of Level 3.

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 currently represent investments in mutual funds at March 31, 2025 that are classified as Level 1. There were no assets or liabilities balances in the LDCP at December 31, 2024. The assets are held in a rabbi trust and are presented in investment in equity securities on the Company’s condensed consolidated balance sheets. The related liabilities of the LDCP are presented in other long-term liabilities and accrued expenses and other liabilities in the Company’s condensed consolidated balance sheets. Changes to the LDCP assets are charged to investment in equity securities – unrealized loss (gain) while the changes to the LDCP liabilities are charged to compensation expense in the in the Company’s condensed consolidated statements of operations. See Note 17, “Benefit Plans” for more information on the LDCP.

Perspective Therapeutics Inc. Equity Securities

At March 31, 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 March 31, 2025 was approximately $24.9 million based on a closing market price of $2.13 per share on March 31, 2025, resulting in an unrealized loss of $12.4 million for the three months ended March 31, 2025. See Note 18, “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 March 31, 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 March 31, 2025 was approximately $4.8 million based on the converted closing market price of approximately $0.02 per share on March 31, 2025, resulting in an unrealized loss on equity securities of $2.5 million for the three months ended March 31, 2025. See Note 18, “Acquisitions” for further discussion of the Radiopharm transaction.

Contingent Consideration

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 March 31, 2025 and December 31, 2024.