Merck & Co.

Merck & Co., Inc. (NYSE: MRK), d.b.a. Merck Sharp & Dohme (MSD) outside the United States and Canada, is an American pharmaceutical company and one of the largest pharmaceutical companies in the world.

The company was established in 1891 as the United States subsidiary of the German company Merck, which was founded in 1668 by the Merck family. Merck & Co. was nationalized by the US government during World War I and subsequently established as an independent American company in 1917. It is the world's seventh largest pharmaceutical company by market capitalization and revenue. Its headquarters is located in Kenilworth, New Jersey.

Merck publishes The Merck Manuals, a series of medical reference books for physicians, nurses, and technicians. These include the Merck Manual of Diagnosis and Therapy, the world's best-selling medical reference. The Merck Index, a compendium of chemical compounds, was formerly published by Merck & Co. before being acquired by the Royal Society of Chemistry in 2012.