The SEC sends a Wells notice to a company or an individual after its staff has determined that sufficient wrongdoing has occurred to warrant civil claims being filed. The notice gives the recipient a chance to try to dissuade the SEC from taking action. In some cases, the SEC has decided to refrain from filing a complaint after sending a Wells notice. Under a provision of the Dodd-Frank bill, the SEC must bring an action within 180 days, though the director of enforcement can extend the deadline with agreement of the recipient of the notice.

Evidence Rules

The SEC, which is a civil enforcement agency, typically coordinates with federal prosecutors who pursue criminal claims in insider-trading cases, said former SEC lawyers and prosecutors. While the SEC often brings insider-trading claims using circumstantial evidence, criminal prosecutors face a higher burden of proof at trial, which can prolong investigations as they seek to pin down needed corroborating witnesses.

“The Justice Department’s interest is keeping its cards close to its chest, said David Gourevitch, a former SEC attorney now practicing securities law and white-collar defense in New York.

Civil cases allow broad discovery of depositions and documents that could give defendants a preview of the evidence for the government’s potential criminal case, Gourevitch said.

Gilman Cooperates

Prosecutors say Martoma received illegal inside information on the trial of an Alzheimer’s drug being conducted by Elan and Wyeth from Sidney Gilman, 80, a doctor involved in the tests. Gilman has reached a non-prosecution agreement with the government and will testify against Martoma, prosecutors said. Gilman earlier this week quit his neurology research position at the University of Michigan, Pete Barkey, a spokesman for the school in Ann Arbor, said in an e-mail.

‘‘It appears they’ve got substantial evidence against Martoma, so he would be looking to cut as good a deal as he can, and that’s through cooperation,” said William Mateja, a former federal prosecutor who is now a principal at law firm Fish & Richardson P.C. in Dallas. “There’s always been smoke around Cohen,” he said, referring to the involvement of former SAC Capital employees in other cases. “But there’s never been the direct link. Criminal prosecutors need that direct link.”

Cohen was deposed by the SEC earlier this year about trades in Elan and Wyeth that he and the firm made, Tom Conheeney, SAC president, told investors on Wednesday’s call. Cohen answered all the SEC’s questions, he said.

“Mathew Martoma was an exceptional portfolio manager who succeeded through hard work and the dogged pursuit of information in the public domain,” his lawyer, Charles Stillman, said last week in an e-mailed statement, adding that he expected Martoma to be fully exonerated.