In 1939, Eric Warburg of the Warburg banking family founded a company under the name E.M. Warburg & Co. Its first address was 52 William Street, New York, the Kuhn Loeb building. Throughout the early post-war period, the firm was a small office of 20 employees. In 1966, E.M. Warburg merged with Lionel I. Pincus & Co, forming a new company that eventually became known as E.M. Warburg, Pincus & Co. In 1965, when Eric Warburg retired to Germany, control was handed to Lionel Pincus, a partner in the Ladenburg Thalmann investment bank, and the working language of the office switched from German to English.