Citigroup said on Monday that Vice Chairman Michael Klein would leave the largest U.S. bank by assets to pursue other opportunities.
Klein's departure came four months after Citigroup Chief Executive Vikram Pandit installed former Morgan Stanley colleague John Havens as chief executive of the institutional clients group.
Klein, 44, became chairman of that group, but no longer had day-to-day responsibility for businesses.
The 23-year Citigroup veteran was once considered a potential candidate to eventually become the company's chief executive, a job Pandit took in December.
Before becoming vice chairman, Klein was co-chief executive of Citigroup's markets and banking unit, which included investment banking.
Citigroup in March granted Klein $19.3 million in deferred cash and stock awards as an incentive to keep him.
Klein is the latest of many top Citigroup executives to depart since Pandit became chief executive.
Pandit has overhauled top management as he tries to shed assets, slash costs, and stem write-downs tied to sub prime mortgages, other debt and consumer credit.
Citigroup on Friday posted a milder-than-expected $2.5 billion second-quarter loss.
In a statement, Pandit called Klein "a uniquely talented individual and partners" who has made "invaluable contributions" to the bank.
Klein in a statement said "it has been particularly important for me to assist the company during this challenging year in the markets and in the management succession at the firm." Citigroup executives were not immediately available for comment, a spokeswoman said.