After Multibillion-Dollar Loss, JPMorgan Continues to Revamp Two senior executives at JPMorgan Chase are expected to leave by the end of the year, in the latest round of management reshuffling after the bank's multibillion-dollar trading loss. Irene Tse -- who headed up the North American arm of the chief investment office, the powerful but previously little known unit at the center of the trading mishap -- is leaving to start her own hedge fund. Barry Zubrow, who currently runs the bank's regulatory affairs, is expected to cede his current position by January, according to several current and former executives with knowledge of the move. The exits come in the aftermath of trading blunder, which stemmed from a soured credit bet. The losses have been a rare black eye for Jamie Dimon, JPMorgan's chief executive, once considered among the most skilled risk managers on Wall Street. As chief risk officer at the bank from 2007 to January 2012, Mr. Zubrow has been associated with the trading losses. Ms. Tse, meanwhile, joined the bank in early 2011 from hedge fund Duquesne Capital Management to take over as head of the North American trading desk. News of Mr. Zubrow's move was previously reported by the Wall Street Journal. As it works to move beyond the trading losses and reassure skittish investors, JPMorgan has revamped parts of its organization. The bank has appointed a new head of the chief investment unit to succeed Ina Drew, one of the most notable casualties of the trading mess. The bank has also promoted a number of younger executives, including Mike Cavanagh and Daniel Pinto to head up a united corporate and investment bank. Mr. Cavanagh is leading the cleanup operation. During Mr. Dimon's nearly six-year reign, the bank has undergone a number of management shuffles. Few of the executives who made up Mr. Dimon's inner circle during the financial crisis - including Bill Winters, Steve Black and Heidi Miller - remain. A spokesman for the bank declined to comment.