Merck & Co.

The Merck family apothecary opened in Darmstadt, Germany, in 1668. In 1891 George Merck emigrated to the United States to set up the business that became Merck & Co., Inc.⁠[1]

Merck & Co. was founded in the United States on January 1, 1891, and the first Merck Manual was published in 1899.⁠[2]

Merck KGaA states that its U.S. office, founded in 1887, later became a separate entity and was expropriated in 1917 because of World War I. Since then two unaffiliated companies have used the Merck name: Merck & Co., Inc. holds the rights to the MERCK trademark in the United States and Canada and is known as MSD (Merck Sharp & Dohme) outside those two countries.⁠[3]

In 1953 Merck & Co., Inc. merged with Sharp & Dohme to create MSD. Its UK subsidiary, Merck Sharp & Dohme Limited, has no direct connection to the German company Merck KGaA.⁠[1]

In 1987 then-CEO Roy Vagelos committed Merck to donating Mectizan to help eliminate river blindness “as much as needed for as long as needed,” creating the Mectizan Donation Program.⁠[2]

In 1989 the company, known in China as MSD, transferred what was then the world’s most advanced genetically engineered hepatitis B vaccine production technology to China at zero profit. MSD is the trade name of Merck & Co., Inc., Rahway, New Jersey.⁠[4]

On September 30, 2004, Merck announced a voluntary worldwide withdrawal of VIOXX (rofecoxib), based on APPROVe trial data showing an increased relative risk for confirmed cardiovascular events beginning after 18 months of treatment compared with placebo. Then-CEO Raymond V. Gilmartin said, “We are taking this action because we believe it best serves the interests of patients.”⁠[5]

On November 9, 2007, Merck entered into an agreement to pay, if certain conditions were met, a fixed amount of $4.85 billion into a fund for qualifying claims, resolving pending or tolled state and federal myocardial infarction and ischemic stroke claims involving VIOXX in the United States.⁠[6]

On November 3, 2009, Merck and Schering-Plough announced that they would complete their merger that day. Schering-Plough shareholders received 0.5767 shares of the newly combined company and $10.50 in cash for each share. Schering-Plough changed its name to Merck, and the combined company’s common stock would trade under the ticker MRK on the New York Stock Exchange.⁠[7]

On November 30, 2010, Merck’s board elected Kenneth C. Frazier, then president, as chief executive officer and president and a board member effective January 1, 2011, with Richard T. Clark continuing as chairman. Frazier had joined Merck in 1992 and later served as executive vice president and general counsel.⁠[8]

On September 4, 2014, the U.S. Food and Drug Administration granted accelerated approval to KEYTRUDA (pembrolizumab) for patients with unresectable or metastatic melanoma and disease progression following ipilimumab and, if BRAF V600 mutation positive, a BRAF inhibitor. It was the first anti-PD-1 therapy approved in the United States.⁠[9]

On January 15, 2016, Merck KGaA said the English High Court had found that MSD breached an agreement with the company by using “Merck” alone in the United Kingdom. A 1955 pact, revised in 1970, gave Merck & Co. the Merck name only in the United States and Canada. Merck & Co. said it disagreed with the ruling, which “will be appealed.”⁠[10]

In May 2020 Merck, then headquartered in Kenilworth, New Jersey, planned to consolidate its New Jersey campuses into a single headquarters location in Rahway by the end of 2023. It named Organon as the company for the pending spin-off of its women’s health, legacy products and biosimilars businesses, expected to be completed by the end of the first half of 2021.⁠[11]

On February 4, 2021, Merck announced that Kenneth C. Frazier would step down as CEO on June 30, 2021, and serve as executive chairman, and that the board had elected Robert M. Davis, executive vice president and chief financial officer, as his successor effective July 1, 2021. Davis had joined Merck as CFO in 2014 after working at Baxter.⁠[12]

On June 3, 2021, Merck announced that it had completed the spinoff of Organon & Co., whose shares trade on the New York Stock Exchange under the symbol OGN. Merck received a distribution of approximately $9 billion from Organon.⁠[13]

On June 16, 2023, Merck completed its acquisition of Prometheus Biosciences for $200.00 per share in cash, a total equity value of approximately $10.8 billion, making Prometheus a wholly owned subsidiary. Its lead candidate, PRA-023 (MK-7240), is a monoclonal antibody targeting TL1A for ulcerative colitis, Crohn’s disease and other autoimmune conditions.⁠[14]

In October 2025 Merck, through a subsidiary, acquired all outstanding shares of Verona Pharma for $107 per American Depositary Share, a transaction valued at approximately $10 billion. Verona’s Ohtuvayre, a selective dual inhibitor of phosphodiesterase 3 and 4 (PDE3 and PDE4), was approved by the FDA in June 2024 for the maintenance treatment of chronic obstructive pulmonary disease in adults.⁠[15]

The company has two operating segments, Pharmaceutical and Animal Health. In 2025 its China business contracted significantly due to lower sales of Gardasil/Gardasil 9, whose global sales fell to $5,233 million from $8,583 million in 2024. KEYTRUDA patents expire in 2028 in the United States and China and in 2031 in major European Union markets.⁠[16]

As of December 31, 2025, the company had approximately 75,000 employees.⁠[17]

On January 7, 2026, Merck announced the successful completion of its cash tender offer for Cidara Therapeutics at $221.50 per share; Cidara would become a wholly owned subsidiary and its stock would no longer trade on the Nasdaq Global Market. Cidara’s CD388 is an investigational drug-Fc conjugate designed to prevent influenza infection in individuals at higher risk of influenza complications.⁠[18]

On February 3, 2026, Merck announced full-year 2025 worldwide sales of $65.0 billion, up 1% (2% excluding foreign exchange), and KEYTRUDA/KEYTRUDA QLEX sales of $31.7 billion, up 7%. Net income attributable to Merck & Co., Inc. was $18,254 million (2024: $17,117 million), and GAAP earnings per share were $7.28.⁠[19]

In the third quarter of 2026, ended September 30, Merck’s worldwide sales were $18,085 million, up 5% from $17,276 million a year earlier, and net income attributable to Merck & Co., Inc. was $5,065 million, or $2.04 per diluted share. KEYTRUDA sales were $7,771 million, down 5%, with a further $830 million from KEYTRUDA QLEX.⁠[20]