The FBI has opened an investigation into the losses racked up at JPMorgan Chase, increasing the pressure on the bank, which is already has Wall Street regulators looking at last week's massive trading losses.
Revelation of the move by the US Justice Department came as Jamie Dimon was given a bloody nose by investors yesterday as 40 per cent of JPMorgan Chase's shareholders voted to strip him of the bank's chairmanship.
The inquiry into potential wrongdoing at JPMorgan, which is at an early stage, is expected to look at the bank's accounting methods and public statements.
Facing his investors for the first time since announcing a $2.3bn (£1.4bn) loss on complex derivatives on Thursday, the previously unassailable chairman and chief executive of JPMorgan faced a torrent of criticism at the company's annual meeting in Tampa, Florida.
Mr Dimon's vociferous opposition to greater banking regulations and his determination to swim against the corporate governance tide by clinging to JPMorgan's top two roles were among the shareholders' biggest bugbears. Both stances made the kind of loss JPMorgan had just seen more likely, they argued.
The Reverend Seamus Finn, representing shareholders from the Catholic organisation Missionary Oblates of Mary Immaculate, said that investors were getting used to hearing Mr Dimon apologise – even if it has previously been about the continuing crisis in the US housing market. "We heard the same refrain: We have learnt from our mistakes. This will never be allowed to happen again. I can't help wondering if you are listening," Mr Finn said.
Another shareholder accused Mr Dimon and other banks of doing his best to "demoralise the major regulators" by consistently challenging their proposals. Another urged the chairman and chief executive to "very publicly switch direction to become a strong advocate of financial regulation".
Mr Dimon defended his right to "engage" with the regulators and insisted he "believes in strong, simple, good regulation".
Lisa Lindsley, who favoured stripping Mr Dimon of his chairmanship, said independent board leadership was in the investors' best interest. "An all-powerful CEO is his own boss. Looking for an infallible CEO is a fool's errand."
The California Public Employees' Retirement System (Calpers), the largest pension fund in the US, led calls to relieve Mr Dimon of his chairmanship yesterday.
Some shareholders praised the record of JPMorgan, while Mr Dimon reiterated that "this is an egregious error," before adding: "but at the end of the day we have a fabulous company."
Mr Dimon's $23m (£14m) pay package for 2011 was also voted through by 91.5 per cent of investors. But he held open the prospect of "clawing back" some executive bonuses in the light of the trading loss. Ina Drew, who resigned as chief investment officer this week following the trading loss, is thought to be a key contender for such a move.
Noting that JPMorgan "is one of the best managed banks," US President Barack Obama told ABC's The View: "You could have a bank that isn't as strong, isn't as profitable, making those same bets and we might have had to step in. Which is exactly why Wall Street reform is so important."