Sigma-Aldrich, formally known as MilliporeSigma, is an American company specializing in chemicals, life sciences, and biotechnology. Founded in 1975 through the merger of Sigma Chemical Company and Aldrich Chemical Company, it expanded significantly through acquisitions and now employs over 9,600 people. The company operates in about 40 countries and has its U.S. headquarters in St. Louis, Missouri, and Burlington, Massachusetts.
In 2015, Sigma-Aldrich was acquired by the multinational chemical conglomerate Merck Group for $17 billion. It now operates as part of Merck's life science division, MilliporeSigma, headquartered in Burlington, Massachusetts.