The Business On: Steven Cohen, SAC Capital

The man with the shark?

This titan of the hedge fund industry does indeed have a decomposing shark at home in Connecticut, where his 14-acre estate is home to an astonishing collection of art, including that Damien Hirst to which you refer. But these days his focus is on sharks of a different kind, enemies in the federal government who seem out to get him.

Prosecutors? Politicians?

Yes and yes. SAC Capital, Mr Cohen's firm, has been firmly denying rumours of insider trading for years, but prosecutors in New York, fresh from discovering insider deals at Raj Rajaratnam's Galleon Group, spread their dragnet further and arrested two former SAC traders earlier this year. One pleaded guilty last month. SAC said it was "outraged" to discover the transgressions. Now, on Capitol Hill, Senator Chuck Grassley's Ways and Means Committee has started an investigation, too.

Why so much suspicion?

SAC has been an extraordinarily successful trading operation, and Mr Cohen has been an extraordinarily successful trader. His eponymous SAC Capital grew from $25m under management in 1994 to $12bn now. Mr Cohen himself is worth $8bn.

Any evidence against Mr Cohen personally?

No suggestion of any wrongdoing from any of the current investigations, no. In a bizarre spat with his ex-wife two years ago, her lawsuit against him accused him of insider trading early in his career, but she dropped the suit.

He must be getting fed up with the innuendo

Too right. He even took to the pages of Vanity Fair last summer to give only the second interview in his career and to explain that he was mystified by the rumours. "It was like a circus, a fucking circus. Well, things are finally calming down. The press is moving on. This story will be the last anyone reads about me for a while, I think."

Er, that turned out to be optimistic

Too right. Now, over to Senator Grassley.