The five year statute of limitations on insider trading is soon to expire for trades made July 21, 2008, by SAC Capital Advisors LP, Cohen's hedge fund, the Journal reported Friday.
Authorities allege trades that began that day were based on confidential information that helped SAC avoid losses of $276 million.
The insider information allegedly came from a neurologist who was aware negative results in drug trials were about to send the share prices of two companies lower.
A trial over the case charging Cohen associate Mathew Martoma with insider trading is scheduled to begin Nov. 4, but so far Martoma has yet to provide authorities with information that implicates Cohen, sources told the Journal.
Martoma's case involves transactions having to do with drug companies Elan and Pfizer's Wyeth, CNNMoney reported.
Rapid growth and unusually positive trading results brought suspicion on SAC, which has become part of a prolonged insider trading investigation that has included 73 convictions and guilty pleas among 81 persons charged with various trading violations.
Among the cases that have reached their conclusions, six have ended with guilty pleas or convictions of former SAC employees. In addition to Martoma, two other SAC employees have been charged and are expected to contest the charges in court, the Journal said.
Regulators could still charge Cohen on civil charges in which the burden of proof can be based on a preponderance of evidence, as opposed to a criminal case, which requires proof beyond a reasonable doubt to reach a guilty verdict.