Merck & Co Inc (NYSE: MRK) is a pharmaceutical company that discovers, develops, manufactures, and markets prescription medicines, vaccines, and animal health products. It makes money primarily through direct product sales of patented pharmaceuticals and vaccines, plus alliance revenue from co-commercialization agreements with partners. The company operates two segments: Pharmaceutical and Animal Health. Total sales reached $65.0B in FY2025, up from $64.2B in FY2024 and $60.1B in FY2023. The Pharmaceutical segment generated $58.1B in FY2025 sales, anchored by oncology drug Keytruda/Keytruda Qlex at $31.7B, making it by far the single largest revenue driver. Other material products include Gardasil/Gardasil 9 ($5.2B FY2025), Januvia/Janumet ($2.5B FY2025), Winrevair ($1.4B FY2025), and alliance revenue from Lynparza ($1.5B FY2025) and Lenvima ($1.1B FY2025). The Animal Health segment sells veterinary pharmaceuticals, vaccines, and digital identification and traceability products to veterinarians, distributors, animal producers, farmers, and pet owners.

Revenue model

Transactional product sales of patented prescription drugs, vaccines, and animal health products, supplemented by alliance revenue from co-commercialization agreements (Lynparza, Lenvima). Revenue is recognized at point of sale to wholesalers, distributors, and direct customers.

Products and services

Pharmaceutical: Keytruda/Keytruda Qlex (oncology), Gardasil/Gardasil 9 (HPV vaccine), Januvia/Janumet (diabetes), Winrevair (pulmonary arterial hypertension), Bridion (anesthesia reversal), ProQuad/M-M-R II/Varivax (vaccines), Prevymis (antiviral), alliance products Lynparza and Lenvima. Animal Health: veterinary pharmaceuticals, vaccines, health management solutions, and digitally connected identification, traceability and monitoring products.

Customers and end markets

Pharmaceutical end markets: oncology, infectious disease, cardiovascular, diabetes, and vaccine markets. Animal Health customers include veterinarians, distributors, animal producers, farmers, and pet owners across livestock and companion animal species.

Value-chain role

Vertically integrated drug developer and manufacturer. Conducts internal R&D, manufactures products, and sells directly and through distribution channels. Also acts as alliance partner in co-commercialization arrangements.

Geographic exposure

The filing excerpts do not provide a specific geographic revenue breakdown. The company files with the SEC as a U.S.-domiciled issuer.

Source: SEC 10-K, filed 2026-02-24

Industry: Pharmaceutical Preparations Peers: Bristol-Myers Squibb Co Catalent, Inc. Eli Lilly and Co Johnson & Johnson Organon & Co Pfizer Inc Royalty Pharma PLC Viatris Inc Zoetis Inc