Merck & Co., Inc. (MRK)

Merck & Co., Inc. is a global health care company that delivers innovative health solutions through prescription medicines, including biologic therapies, vaccines and animal health products. Its operations are managed principally on a product basis. In 2025 the company reported total sales of $65.0 billion, compared with $64.2 billion in 2024 and $60.1 billion in 2023.

The company has two reportable segments. The Pharmaceutical segment (2025 sales of $58.1 billion) covers human health pharmaceuticals and vaccines. Its largest product is Keytruda (anti-PD-1 therapy for many cancers, including the subcutaneous Keytruda Qlex), with $31.7 billion of sales. Other products include the Gardasil/Gardasil 9 HPV vaccines, Januvia/Janumet for type 2 diabetes, the ProQuad/M-M-R II/Varivax vaccines, Bridion, Winrevair for pulmonary arterial hypertension, Prevymis, Vaxneuvance and Capvaxive pneumococcal vaccines, and Welireg. It also books alliance revenue from Lynparza and Lenvima. The portfolio further includes HIV treatments (Isentress, Delstrigo, Pifeltro), Belsomra for insomnia, Enflonsia for RSV prevention, and cardiometabolic and respiratory products such as Adempas, Verquvo and Ohtuvayre. The Animal Health segment (2025 sales of $6.4 billion) discovers, develops, manufactures and markets veterinary pharmaceuticals, vaccines, and health management solutions and services. It also offers digitally connected identification, traceability and monitoring products. Livestock sales were $3.9 billion and companion animal sales $2.5 billion. Products include the Bravecto and Sentinel parasite control lines, Nobivac vaccines, Numelvi, and Allflex and Sure Petcare identification and monitoring solutions.

Pharmaceutical products are sold primarily to drug wholesalers and retailers, hospitals, government agencies, and managed health care providers such as health maintenance organizations and pharmacy benefit managers. Vaccines are sold mainly to physicians, wholesalers, distributors and government entities. Animal health products are sold to veterinarians, distributors, animal producers, farmers and pet owners. The company obtains regulatory approvals in major markets including the U.S., the European Union, China and Japan, and collaborates with other companies on certain products, such as Pfizer and Astellas on Keytruda combinations.