Washington:  When bank regulators wanted daily profit and loss statements from JPMorgan Chase's investment division, the bank initially refused. When examiners issued recommendations the bank didn't like, executives yelled and called the federal officials 'stupid'.

At one point, the top brass at the prestigious bank ambushed a junior bank examiner, becoming 'loud and combative' when he disclosed disputed results of an exam.

Those incidents are part of a rare and detailed look into the interactions between Washington regulators and Wall Street, described in congressional testimonies and a Senate report on a massive trading loss at JPMorgan.

The documents and testimonies show a dynamic: Executives at the nation's largest bank at times bullied federal examiners. The examiners at times gave in. In a six-hour hearing on Friday, top officials at the Office of the Comptroller of the Currency (OCC), which regulates the biggest banks, came under fire from lawmakers for tolerating impudent behaviour by JPMorgan executives.

"We had a $157 billion high-risk derivatives portfolio here that the OCC hardly knew existed. And that strikes me as being a hidden financial risk. Is that the way the OCC views it?" questioned Senator Carl Levin, who chairs the Permanent Subcommittee on Investigations, which issued the report on the Wall Street giant's $6.2 billion trading blunder.

"I would view it that way, yes, sir," answered Scott Waterhouse, the primary OCC official in charge of JPMorgan. "Now, is this something that — that OCC has to or is expected to have to ferret out, or is this something that the banks are supposed to disclose?" Levin shot back. Waterhouse responded: "The responsibility would lie first and foremost with management. . . . And then . . . we ought to be informed, receive the regular reports, and understand the risks as they transpire."