Under Sanford I. Weill, Willumstad helped to steer the 1998 merger of Travelers Group and Citicorp. From 2000 to 2003, he was the chairman and CEO of Citigroup's Global Consumer Group. He was named President of Citigroup in 2002, and assumed the post of Chief Operating Officer in 2003, while continuing to serve as CEO and President of Citibank North America.[1] Some suggested that he had been passed over for CEO in favour of Charles Prince, despite being in charge of Citi's largest business.[2][3]
Willumstad left Citigroup in July 2005, saying that he wanted to run a major company, after CEO Charles Prince decided to take back control of operations.[4]
Willumstad served as the chairman of the board of directors of AIG from 2006 until 2008, after Maurice R. Greenberg was forced to resign.
Willumstad became CEO on June 15, 2008, after Martin J. Sullivan was ousted.[4] One of Willumstad's initiatives was to repair the rift with Greenberg.[6] In September 2008, Edward M. Liddy succeeded [7] Willumstad to oversee the company's government-financed asset sale.[8] Willumstad refused a $22 million severance payment for his three months' work at AIG[9][10] since he was never able to enact his strategy. AIG's stock price declined 97% during his short tenure due to preexisting company conditions.[citation needed]