James "Jamie" Dimon (born March 13, 1956, New York City) is an American businessman best known as the chairman and chief executive officer (CEO) of JPMorgan Chase & Co., the largest bank in the United States by assets[1][3]. Dimon began his career as a management consultant at Boston Consulting Group before earning an MBA from Harvard Business School in 1982 and joining American Express, where he worked under financier Sandy Weill, who became his mentor[3]. Dimon’s early leadership roles included serving as chief financial officer and then president of Commercial Credit, which evolved into part of Citigroup. From 1990 to 1998, he was chief operating officer of both Travelers Insurance and its brokerage subsidiary Smith Barney, later becoming president of Citigroup in 1998 after the merger of Travelers and Citicorp[2][3]. Following a leadership conflict, he left Citigroup in 1998. In 2000, Dimon became CEO of Bank One, the fifth-largest U.S. bank at the time, where he focused on revitalization and operational efficiency[3]. Bank One merged with JPMorgan Chase in 2004, and Dimon was named president and chief operating officer of the combined company. He became CEO of JPMorgan Chase on January 1, 2006, and chairman in 2007[1][2][3]. Under Dimon's leadership, JPMorgan Chase expanded significantly through major acquisitions during and after the 2007–08 financial crisis, including Bear Stearns and Washington Mutual, which strengthened its consumer banking and investment banking positions[1][4]. He is credited with steering JPMorgan Chase through turbulent periods, notably helping to stabilize the banking sector during the 2008 crisis and again in 2023 by coordinating a $30 billion effort among major banks to support First Republic Bank following failures of other regional banks[4]. Dimon’s tenure has seen JPMorgan Chase become a leading global financial institution in terms of assets, market capitalization, and stock value, making him one of the most prominent figures in American banking[3][4].