SAC Capital's January performance also lags that of other prominent stock-trading funds, including Omega Advisors and Jana Partners, both of which were up about 5 percent, according to people who have reviewed their numbers.
However modest, SAC's upside in January extended what has proved to be a remarkable winning streak for the $14 billion money manager who helms SAC. It also comes during a period in which the firm has come under legal and investor fire.
Under founder Steve Cohen, SAC over the years has embraced a rapid-fire trading style fueled by heavy analysis of companies, sectors, and the market environment. Yet a series of cases filed by U.S. prosecutors, which have already resulted in three former employees pleading guilty to insider-trading charges, suggest that SAC's success was also fueled in part by illegally-obtained stock tips.
Some of the hedge fund's investors,spooked by a new Justice Department complaint implicating Cohen personally in a situation involving alleged insider trading, have pulled money from the firm in recent months.
The trader charged in that case, Mathew Martoma, has pleaded not guilty, and Cohen has said in statements that both he and his company acted appropriately.
(Read more: SAC Capital's Martoma Pleads Not Guilty)
Ahead of a looming Feb. 15 first-quarter redemption deadline,SAC is reportedly expecting at least an additional $1 billion in investor clawbacks.