Robert Edward Rubin (born August 29, 1938) served as the 70th United States Secretary of the Treasury during both the first and second Clinton administrations. Before his government service, he spent 26 years at Goldman Sachs. His most prominent post-government role was as Director and Senior Counselor of Citigroup, where he performed ongoing advisory and representational roles for the firm. From November to December 2007, he served temporarily as Chairman of Citigroup. On January 9, 2009 Citigroup announced his resignation, after having been criticized for his performance. He received more than $126 million in cash and stock during his eight years at Citigroup.

Born in New York in a Jewish family, Rubin moved to Miami Beach, Florida at an early age and graduated from Miami Beach High School. In 1960, Rubin graduated summa cum laude with a B.A. in economics from Harvard College. He then attended Harvard Law School for three days before leaving to see the world. He later attended the London School of Economics after graduation and received an LL.B. from Yale Law School in 1964.

Rubin began his career as an attorney at the firm of Cleary, Gottlieb, Steen & Hamilton in New York City. He joined Goldman Sachs in 1966 as an associate in the risk arbitrage department . Rubin proved his skills at the intricate art of investing his firm's capital in high-reward arbitrage opportunities and became a general partner in 1971. He joined the management committee in 1980 along with fellow Democrat Jon Corzine, later a U.S. senator and governor of New Jersey. Rubin was Vice Chairman and Co-Chief Operating Officer from 1987 to 1990. From the end of 1990 to 1992, Rubin served as Co-Chairman and Co-Senior Partner along with Stephen Friedman.