UNITED States federal prosecutors took a double-barreled approach against hedge fund billionaire Steven A. Cohen yesterday, unveiling criminal fraud charges against his SAC Capital Advisors LP and a separate civil case seeking to freeze assets and money laundering penalties.

The actions cap a seven-year probe, and could imperil the future of SAC, a roughly US$15 billion hedge fund that has posted some of the best returns in its industry and established Cohen, 57, as one of his generation's best traders.

Cohen was not personally charged, but the very rare move by the US Department of Justice could end his career managing outside money, and suggests prosecutors and the FBI found a pervasiveness of wrongdoing at SAC.

A spokesman for SAC and a lawyer for Cohen did not immediately respond to messages for comment yesterday.

Many Wall Street firms that lend money to and trade with SAC are likely to stop because of the criminal case, although the firm might still be able to operate because more than half of its assets belong to Cohen and employees.

The indictment in US District Court in New York accused SAC and various affiliates of four criminal counts of securities fraud and one count of wire fraud. Cohen had been charged last week in a related civil case brought by the Securities and Exchange Commission, and said he'd fight those charges.

Cohen, who lives in Greenwich, Connecticut, is one of the richest men in America. He is among the handful of upper-tier hedge fund managers on Wall Street who pull in about US$1 billion a year.

The indictment accused SAC of "systematic insider trading" that enabled it to generate hundreds of millions of dollars of illegal profits and avoided losses.

It said that the scheme ran from roughly 1999 to 2010, and was designed to boost SAC's returns and fees.

The government said SAC encouraged workers to relentlessly pursue an "information edge" that overwhelmed the firm's "limited" compliance systems.

"There was no meaningful commitment to ensure that such 'edge' came from legitimate research and not inside information," the indictment said. "The predictable and foreseeable result ... was systematic insider trading."