Merck & Co., Inc.

Business Overview

Merck & Co., Inc. (Merck or the Company) is a global health care company that delivers innovative health solutions through its prescription medicines, including biologic therapies, vaccines and animal health products. The Company’s operations are principally managed on a product basis and include two operating segments, Pharmaceutical and Animal Health, both of which are reportable segments. The Pharmaceutical segment includes human health pharmaceutical and vaccine products. Human health pharmaceutical products consist of therapeutic and preventive agents, generally sold by prescription, for the treatment of human disorders. The Company sells these human health pharmaceutical products primarily to drug wholesalers and retailers, hospitals, government agencies, and managed health care providers such as health maintenance organizations, pharmacy benefit managers and other institutions. Human health vaccine products consist of preventive pediatric, adolescent and adult vaccines. The Company sells these human health vaccines primarily to physicians, wholesalers, distributors and government entities. The Animal Health segment discovers, develops, manufactures and markets a wide range of veterinary pharmaceutical and vaccine products, as well as health management solutions and services, for the prevention, treatment and control of disease in all major livestock and companion animal species. The Company also offers an extensive suite of digitally connected identification, traceability and monitoring products. The Company sells its products to veterinarians, distributors, animal producers, farmers and pet owners. All product or service marks appearing in type form different from that of the surrounding text are trademarks or service marks owned, licensed to, promoted or distributed by Merck, its subsidiaries or affiliates, except as noted. All other trademarks or service marks are those of their respective owners. Product Sales Total Company sales, including sales of the Company’s top pharmaceutical products, as well as sales of animal health products, were as follows: ($ in millions) 2025 2024 2023 Total Sales $ 65,011 $ 64,168 $ 60,115 Pharmaceutical 58,142 57,400 53,583 Keytruda/Keytruda Qlex 31,680 29,482 25,011 Gardasil/Gardasil 9 5,233 8,583 8,886 Januvia/Janumet 2,544 2,268 3,366 ProQuad/M-M-R II /Varivax 2,451 2,485 2,368 Bridion 1,841 1,764 1,842 Alliance revenue - Lynparza (1) 1,450 1,311 1,199 Winrevair 1,443 419 — Alliance revenue - Lenvima (1) 1,053 1,010 960 Prevymis 978 785 605 Vaxneuvance 825 808 665 Capvaxive 759 97 — Welireg 716 509 218 Animal Health 6,354 5,877 5,625 Livestock 3,896 3,462 3,337 Companion Animal 2,458 2,415 2,288 Other Revenues (2) 515 891 907 (1) Alliance revenue represents Merck’s share of profits, which are product sales net of cost of sales and commercialization costs. (2) Other revenues are primarily comprised of miscellaneous corporate revenues, including revenue hedging activities, as well as revenue from third-party manufacturing arrangements. Pharmaceutical The Pharmaceutical segment includes human health pharmaceutical and vaccine products. Human health pharmaceutical products consist of therapeutic and preventive agents, generally sold by prescription, for the treatment of human disorders. Human health vaccine products consist of preventive pediatric, adolescent and adult vaccines.

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