The one thing that could compel Jamie Dimon to resign immediately

Jamie Dimon has staying power. He stayed with JPMorgan throughout the financial crisis. He stayed with JPMorgan when it became apparent that the CIO had made a huge loss. And he's still at JPMorgan even after the bank set aside $9bn in pre-tax legal expenses, surpassing the previous record at Citigroup under Sandy Weill. Despite all this, Dimon still has the support of JPMorgan board members who still extol him with the moniker, 'the best manager ever."

So, what would it take for Dimon to go on?

Chris Wheeler, a veteran banking analyst and director at Mediobanca in London, thinks he has the answer: Dimon will be obliged to resign instantly if it becomes apparent that he's understated the extent to which JPMorgan itself was involved in selling dodgy mortgage backed securities (mbs) to investors.

So far, JPMorgan has indicated that 80% of the mortgage backed securities under examination were created by Washington Mutual and Bear Stearns, points out Wheeler. However, JPMorgan has yet to reach a conclusive settlement. If the final settlement reveals that JPMorgan was responsible for writing a higher proportion of the contested securities than Dimon has hitherto indicated, his days will be strictly numbered.

"Dimon will be stuffed if litigation reveals that most of the charges relate to JPMorgan rather than Bear Stearns and WaMu," says Wheeler. "If this is JPMorgan-related, it will have happened under Dimon's watch."

Ominously, a JPMorgan employee is said to be 'cooperating' with a U.S. Department of Justice investigation into the sale of residential mortgage backed securities (RMBS) by the bank.

In the meantime, pay at JPMorgan's investment bank appears to be plummeting. Excluding accounting adjustments, compensation in the corporate and investment bank was just 27% of revenues in the past quarter.

"Your bonus accrual must be way down," pointed out UBS analyst Derek De Vries in last week's conference call. DeVries then asked if this was related to the huge litigation expenses. JPMorgan CFO Marianne Lake said it wasn't, but nor did she deny that this year's JPM bonus pool will be the most diminutive for a long, long time.