Amgen Faces Added IRS Penalties in Profits Dispute

The Internal Revenue Service is seeking further penalties from Amgen over tax years 2016 through 2018, Amgen disclosed in a quarterly report.

Updated on Nov. 4, 2026 in Taxes

Isometric editorial illustration of identical steel drums stacked on a concrete pallet beside a low industrial wall with palm silhouettes, evoking the scale of a multi-year corporate tax liability. — The Internal Revenue Service is seeking further penalties from Amgen over tax years 2016 through 2018, with the drug maker disclosing the proposed penalties in its quarterly report Wednesday. AI Illustration. Upload story photo >

Amgen said the Internal Revenue Service is seeking additional penalties against it in a dispute over profits tied to Puerto Rico. The proposed penalties, first made in September, cover tax years 2016 through 2018 and are substantially similar to those demanded for 2013 through 2015.

Why it matters

The dispute concerns how profits linked to Puerto Rico operations are taxed, and Amgen has acknowledged it may owe the IRS $10.7 billion in taxes, interest and penalties. For U.S. taxpayers and investors tracking large multinational tax disputes, the case shows how the scale of potential liabilities can grow across multiple tax years.

Amgen's quarterly report discloses that it may owe the IRS $10.7 billion in taxes, interest and penalties, a figure the company itself has acknowledged. The final amount of the proposed penalties for 2016 through 2018 has not been determined.

The players

Amgen

Amgen is a major American biotechnology company headquartered in Thousand Oaks, California, known for its large portfolio of biologic medicines.

Internal Revenue Service

The Internal Revenue Service is the U.S. federal agency responsible for administering and enforcing the nation's tax laws.

The details

The IRS proposed penalties in September for tax years 2016 through 2018, matching in substance the penalties sought for 2013 through 2015. Amgen disclosed the proposed penalties in its quarterly report released on Wednesday.

September 2026: IRS proposes penalties against Amgen for tax years 2016-2018.
November 4, 2026: Amgen discloses the further penalty demands in its quarterly report.

Market Dynamics

The IRS's move to apply penalties to tax years 2016 through 2018 extends its earlier demands for 2013 through 2015 in the same Puerto Rico profits dispute. The pattern shows the agency pursuing the issue across successive tax years rather than settling a single period.

For shareholders, the potential $10.7 billion liability could affect Amgen's financial position depending on how the dispute is resolved. Individual investors may want to review the company's quarterly disclosures as the IRS penalty process moves forward.

The takeaway

Large corporate tax disputes can span multiple years, and penalties may be applied period by period. Investors and taxpayers can track these developments through company quarterly filings.