Securities and Exchange Commission Weighs Suing SAC Capital Federal regulators are preparing a civil fraud case against SAC Capital Advisors, the $14 billion hedge fun run by the billionaire investor Steven A. Cohen, according to a call that the fund held with its investors on Wednesday morning. SAC said that it had received a so-called Wells notice from the Securities and Exchange Commission, an indication that the agency is considering an enforcement action against the hedge fund. Last week federal prosecutors accused Mathew Martoma, a former SAC portfolio manager, with corrupting a doctor who provided him with confidential data on a drug trial. The secret information, authorities say, allowed SAC to earn millions and avoid losses totaling $276 million. For the first time in the government's years of investigating SAC over improper trading, the charges connected Mr. Cohen to questionable trades. The S.E.C. also filed a parallel civil case against Mr. Martoma and CR Intrinsic, the SAC unit that employed Mr. Martoma. A spokesman for SAC Capital, Jonathan Gasthalter, has said, "Mr. Cohen and SAC are confident that they have acted appropriately and will continue to cooperate with the government's inquiry." On the call, Tom Conheeney, the president of the SAC, said that Mr. Cohen had been deposed by the S.E.C. related to this matter earlier in the year, and been responsive to all of the commission's questions. A Wells notice from the S.E.C. relates to possible civil action does not imply that the Justice Department is preparing a criminal case against SAC or Mr. Cohen.