Two senior Bear Stearns executives who moved to senior positions at JPMorgan Chase just weeks ago are leaving the bank.

The departure of Jeff Mayer and Craig Overlander comes amid questions about the value of the Bear Stearns mortgage book. The two men had been in charge of the fixed income department at Bear Stearns and were named vice-chairmen of JPMorgan’s investment bank soon after it agreed to buy Bear Stearns in mid-March. The promotion of the pair was seen as a sign of JPMorgan’s commitment to integrating Bear Stearns staff.