James Dimon is sweating. The JP Morgan Chase chief on Tuesday breathed new life into a longstanding spat between bankers and their regulators, who are trying to rein in the financial sector. Speaking during a televised question-and-answer session after an important speech by Federal Reserve chairman Ben Bernanke, Dimon said he feared an onslaught of regulation is why the economy and job creation are sputtering.

Dimon's real nightmare, though, concerns the future of his own bank. JP Morgan and its too-big-to-fail peers - Bank of America, Citigroup, Goldman Sachs and Morgan Stanley - have found themselves in a battle with regulators that will determine their future shape, size and profitability.