Federal Bureau of Investigation agents raided the Connecticut offices of two hedge funds, Diamondback Capital Management LLC and Level Global Investors LP, amid a massive insider-trading investigation.

“The FBI is executing court-authorized search warrants in an ongoing investigation,” said Richard Kolko, an FBI spokesman, who declined to comment further.

Both hedge funds are run by former managers of Steve Cohen’s SAC Capital Advisors.

Level Global, based in Greenwich, Conn., is run by David Ganek, a former SAC Capital trader and art collector. He started Level Global in 2003 and earlier this year reported managing about $4 billion in assets.

Diamondback Capital is based in Stamford, Conn., and was started in 2005 by former managers of SAC Capital. Diamondback oversees more than $5 billion in assets, according to SEC filings.

The move by the FBI follows a story by The Wall Street Journal describing a massive insider-trading investigation that is expected to encompass consultants, investment bankers, hedge fund and mutual fund traders. The investigation is said by people close to the situation to eclipse in size and magnitude past insider trading probes.

A spokesman for Level Global said, “We can confirm that agents from the Federal Bureau of Investigations visited our offices this morning as part of what we believe to be a broader investigation of the financial services industry discussed in media reports over the weekend. We are cooperating fully with the authorities and, at the same time, we are fully operational and continue to work diligently for the benefit of our investors.”

Messages left with Richard Schimel, Diamondback’s co-chief investment officer; and Joel Harary, Diamondback’s general counsel, on their office phones weren’t immediately returned.