Weill, Sanford I. (wĪl) [key], 1933–, American business executive, b. Brooklyn, N.Y. A graduate of Cornell (1955), Sandy Weill went to work for a New York brokerage house, and in 1960 helped found a small brokerage firm that grew into the second largest securities brokerage firm, Shearson Loeb Rhoades, before being acquired by American Express in 1981. Weill became president of American Express but lost a power struggle with the company's chairman and resigned in 1985. In 1986 he became CEO of Commercial Credit, a financial and insurance firm that he grew through acquisitions and mergers into the world's largest financial services, insurance, and brokerage conglomerate, Citigroup, Inc., by 1998. He retired as Citigroup's CEO in 2003, but remained chairman until 2006. The complexities of managing the huge international financial "supermarket" that Citigroup became under Weill's leadership contributed to the company's financial difficulties in 2007.