Lantheus Holdings, Inc. Fair Value Disclosure

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:

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 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 were recorded at fair value by the Company and are adjusted for price changes observable in the market each quarter. The Company recorded the contingent consideration liabilities resulting from the acquisitions of Progenics, Evergreen and Life Molecular at fair value based on inputs that are not observable in the market.

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 invested in corporate-owned life insurance (“COLI”) and mutual funds at December 31, 2025. The mutual funds are classified as Level 1 of the fair value hierarchy because they are valued using quoted market prices. 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 consolidated balance sheets. See Note 18, “Benefit Plans” for more information on the LDCP.

Perspective Therapeutics, Inc. Equity Securities

At December 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 their 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 December 31, 2025 was approximately $32.1 million based on a closing market price of $2.75 per share on December 31, 2025, resulting in an unrealized loss of $5.1 million for the year ended December 31, 2025. The fair value of the Perspective Shares as of December 31, 2024 was approximately $37.3 million based on a closing market price of $3.19 per share on December 31, 2024, resulting in an unrealized loss of $41.0 million for the year ended December 31, 2024. See Note 19, “Acquisitions,” to these consolidated financial statements for further discussion of the Perspective transaction.

Radiopharm Theranostics Limited Equity Securities

At December 31, 2025, the Company held 537,958,513 shares of Radiopharm common stock (“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 their 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 December 31, 2025 was approximately $9.0 million based on the converted closing market price of approximately $0.02 per share on December 31, 2025, resulting in an unrealized loss on equity securities of $3.3 million for the year ended December 31, 2025. The fair value of the Radiopharm Shares as of December 31, 2024 was approximately $2.2 million based on the converted closing market price of approximately $0.01 per share on December 31, 2024, resulting in an unrealized loss on equity securities of $2.6 million for the

year ended December 31, 2024. See Note 19, “Acquisitions” to these consolidated financial statements 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 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 the Company discontinued the production of AZEDRA in the first quarter of 2024 and the Company is not actively advancing 1095. As a result of this assessment, the Company determined the value of the contingent consideration liabilities to be $0 at December 31, 2025 and 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 pay 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 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 DCF approach. The most significant unobservable inputs with respect to these milestone products and Octevy, are the revenue volatility and probabilities of achieving regulatory milestones, respectively. A significant change in probability of payment of the first regulatory milestone payment for Octevy could result in a material fluctuation in the value of the contingent consideration liability.

Life Molecular Imaging Limited

Pursuant to the terms of the Sale and Purchase Agreement (the “LMI Purchase Agreement”) with Life Medical Group Limited (“Life Medical”) in connection with the Company’s acquisition of Life Molecular in July 2025 (see Note 19, “Acquisitions”), the Company is required to make certain earn-out and milestone payments as a percentage of and upon achievement of specified net sales thresholds, respectively, of Neuraceq and certain other imaging and tracing agents in Life Molecular’s pipeline. These contingent cash earn-out and milestone payments total up to $400.0 million.

In addition to the net sales earn-out and milestone payments, the Company also assumed a contingent consideration liability owed to Piramal Holdings SA (“Piramal”), pursuant to an assumed contract (the “Piramal SPA”). The Company is required to make cash payments of up to $30.0 million upon the achievement of specified earnings metrics of Life Molecular, as defined in the Piramal SPA.

The Company estimated the fair value of the contingent consideration liabilities using a Monte Carlo simulation model in a risk-neutral framework, whereby the achievement of the future revenue and other specified earnings metrics associated with the contingent payments were simulated using a geometric Brownian motion model. The most significant unobservable inputs with respect to Neuraceq and other imaging and tracing agents in Life Molecular’s pipeline include revenue volatility and the

probability of commercial success. A significant change in the revenue volatility or forecasted commercial revenue could result in a material fluctuation in the value of the contingent consideration liability.

Unobservable inputs were weighted by the relative fair value of the contingent consideration liability. There were no liabilities with fair values that were measured using Level 3 inputs as of December, 31, 2024.