The House Committee on Oversight and Government treated them cordially, even though the hedge fund ­managers stressed that they were not to blame for the crisis. Mr Soros blamed the “financial system itself”, while James Simons, president of Renaissance Technologies, pointed at credit ratings agencies, which he said had facilitated the sale of “sows’ ears as silk purses” through “fanciful” ratings of mortgage-backed securities.

Kenneth Griffin of Citadel said he did not believe greater regulation of hedge funds was required: “We have not seen hedge funds as a focal point of carnage.”

Henry Waxman, the Democratic chairman of the committee, suggested hedge funds’ rapid growth and high leverage posed potential risks to the broader economy, but he stopped short of blaming the funds, or their trading practices, for the current crisis. But he did question “special tax breaks” that allow the majority of earnings to be treated as capital gains, taxed at as little as 15 per cent.