Raj Rajaratnam (centre) is accused of insider trading in 2007
A leading US hedge fund boss and five other people have been arrested on charges linked to insider trading.
Raj Rajaratnam, founder of the Galleon Group, and the other defendants, are alleged to have pocketed about $20m (£12m) in illegal profits.
They are said to have secured inside information regarding firms including Google, AMD, and Hilton Hotels.
Forbes magazine has featured Mr Rajaratnam on one of its rich lists and estimated that he was worth $1.3bn.
Prosecutors claimed the insider trading also took place at the New Castle hedge fund and Intel Capital, the investment arm of microchip giant Intel.
The others charged in the case include Rajiv Goel, a director of strategic investments at Intel Capital; and Robert Moffat, senior vice president in the systems and technology division of computer group IBM.
They are joined by Anil Kumar, a director at global management-consulting firm McKinsey & Co; and Danielle Chiesi and Mark Kurland of New Castle Partners.
The insider trading is said to have taken place between January and July 2007.
Mr Rajaratnam's bail was set at $100m (£61m) despite a request by prosecutors to deny bail.
It was argued that Mr Rajaratnam was a flight risk, but his lawyer Jim Walden said: "A court's going to learn there's a lot more to this case. There is no way that this man is going to flee."
Mr Walden, called his client a "citizen of the world", stating he has made more than $20m (£12.2m) in charitable donations in the last five years.
US attorney Preet Bharara told a press conference that it was the largest hedge fund case ever prosecuted.
He added that it also marked the first use of court-authorised wiretaps to capture conversations between suspects.
"Greed is not good," said Mr Bharara. "This case should be a wake-up call for Wall Street."
He added that anyone on Wall Street thinking of breaking the law should now be asking themselves "is law enforcement listening?".
Galleon Group, which has up to $7bn in assets under its management, said it had no knowledge of the investigation and intends to "cooperate fully with relevant authorities".