Some of Macris’s bets are now so large that JPMorgan probably can’t unwind them without losing money or roiling financial markets, the former executives said, based on knowledge gleaned from people inside the bank and dealers at other firms. Bruno Iksil, a London-based trader in Macris’s group, gained attention last week after moving markets with his trades, drawing a comparison to Federal Reserve Chairman Ben S. Bernanke’s power in the government-bond market.
“What Bernanke is to the Treasury market, Iksil is to the derivatives market,” Bonnie Baha, head of the global developed credit group at DoubleLine Capital LP in Los Angeles, where she helps oversee $32 billion, said in a telephone interview.