Pfizer, Inc. is an American multinational pharmaceutical corporation headquartered in New York City, and with its research headquarters in Groton, Connecticut, United States. It is the world’s largest pharmaceutical company by revenues. Pfizer was founded by cousins Charles Pfizer and Charles Erhart in New York City in 1849 as a manufacturer of fine chemicals. Pfizer’s discovery ofTerramycin (oxytetracycline) in 1950 put it on a path towards becoming a research-based pharmaceutical company. Pfizer has made numerous acquisitions, including of Warner–Lambert in 2000, Pharmacia in 2003 and Wyeth in 2009, the latter acquired for US$68 billion. Pfizer is listed on the New York Stock Exchange and its shares have been a component of the Dow Jones Industrial Average since April 8, 2004.