(Reuters) - Former SAC Capital Advisors portfolio manager Mathew Martoma said the government is impeding his ability to defend against criminal insider trading charges by trying to link him to an alleged long-running conspiracy for which it has only "vague" details.
In papers filed on Monday night in U.S. District Court in Manhattan, Martoma said he was seeking more information about federal prosecutors' case against him.
The previous week, authorities issued subpoenas seeking testimony from others at SAC Capital, including its founder, billionaire Steven Cohen.
Several current and former SAC employees have been linked to insider trading for periods when they worked at the Stamford, Connecticut-based firm. Martoma and Michael Steinberg, an SAC Capital portfolio manager on leave from the firm, have pleaded not guilty to criminal charges.
Prosecutors accused Martoma of helping SAC avoid millions of dollars of losses by recommending that it sell shares of Elan Corp
In his filing, Martoma said the government's case focuses only on alleged wrongful trades that took place over seven days in July 2008.
But he said prosecutors in recent court papers purposely conflated these trades with an alleged conspiracy described "in vague terms" and "stretching back in time to late 2006" that gave him "an edge."
Martoma said that to defend against this alleged conspiracy, he would effectively be forced to prove the legality of thousands of other Elan and Wyeth trades by him and SAC, which are not part of the government's criminal case.
"The result is that the government proclaims its allegations are narrow and that it need only particularize the limited information relevant to July 2008, but simultaneously accuses Mr. Martoma of much more extensive conduct," the filing said. "The government should not be allowed to have it both ways."
A spokeswoman for U.S. Attorney Preet Bharara in Manhattan declined to comment.
Martoma said he agrees with a July 31 deadline for the government to disclose names of all known co-conspirators, so long as it does not withhold disclosures for strategic reasons.
SAC agreed in March to pay $616 million to settle two U.S. Securities and Exchange Commission civil lawsuits linked to alleged insider trading.
Cohen has not been accused of wrongdoing. It is unclear how the subpoenas will affect outside investors who control roughly $6 billion of SAC's $15 billion of assets. Investors have this year asked to redeem $1.7 billion, and have until June 3 to submit another withdrawal request.
The case is U.S. v. Martoma, U.S. District Court, Southern District of New York, No. 12-cr-00973.
(Reporting by Jonathan Stempel in New York; Editing by David Gregorio)