JPMorgan Chase chief Jamie Dimon insisted yesterday that his bank is solid and that there was no need for rules to block the derivatives trading that dealt it a shock $2 billion loss last month.

In the hot seat in the US Senate over accusations that the giant bank was taking excessive risks in “out of control” proprietary trading, Mr Dimon conceded the loss was a bad management error but also a one-off event that did not require any broad regulatory action.

“We are doing what a bank is supposed to do. We do it every single day,” Mr Dimon told the Senate Banking Committee.

“All of our lines of business remain profitable and continue to serve consumers and businesses,” he said.

“While there are still two weeks left in our second quarter, we expect our quarter to be solidly profitable.”

He said the bank’s capital cushion was large and that global capital rules and some new regulations had plugged the weaknesses in the financial system overall.

Other recent and proposed regulations – including the “Volcker Rule” that would ban active trading of bank assets to generate greater profits – were not so necessary, and were in fact burdens, Mr Dimon said.

“I thought it was unnecessary when it was added on top of the other stuff,” he said of the controversial Volcker Rule, still under consideration by US regulators. With the massive public-funded bailouts of the 2008 financial crisis still fresh in mind, senators questioned Dimon over the kind of risks he was taking with the country’s largest bank.

On May 10, JPMorgan shocked investors in revealing a $2 billion loss in derivatives trading over just six weeks and said an additional $1 billion loss was possible by the end of June.

The New York Times reported that the losses could rise to $5 billion. “Where were the risk controls?” at “a bank renowned for its risk management,” asked the committee chairman, Senator Tim Johnson.

Mr Johnson noted that in April Mr Dimon had downplayed reports of the loss as a “tempest in a teapot.”