Michael Steinberg became SAC Capital Advisors' longest-serving manager to be convicted of insider trading in a government victory that may increase pressure on his former colleague Mathew Martoma to cooperate in the U.S. investigation of founder Steven A. Cohen.

Steinberg, 41, was convicted of conspiracy and securities fraud after a five-week trial in federal court in Manhattan. A jury found him guilty of using illegal tips on technology stocks provided by his former analyst, Jon Horvath, to reap more than $1.4 million in illicit profits. Steinberg faces as many as 25 years in prison when he is sentenced April 25.

Last month, SAC Capital agreed to plead guilty and pay a record $1.8 billion for perpetrating an insider-trading scheme stretching back to 1999 that reaped hundreds of millions of dollars in illicit profits. Federal prosecutors in New York have brought insider-trading cases against 87 people and won convictions against 76 of them as part of a six-year nationwide probe of fund managers, company insiders and so-called expert network firms.

U.S. Atty. Preet Bharara said after SAC's plea that his investigation of the Stamford, Conn., hedge fund's employees continues as investigators seek evidence to link Cohen, 57, to insider trading.

Martoma, 39, who has declined to cooperate with prosecutors in the past, goes on trial in federal court in Manhattan on Jan. 6 on charges that he used illegal tips tied to pharmaceutical company stocks.

With SAC's landmark plea and Steinberg's conviction, Martoma may see cooperating in the probe as a less risky option than trial, said Anthony Sabino, a law professor at St. John's University in New York.

"He has to decide if he now has a greater chance of losing and going to prison and decide if it's too late for a plea bargain," Sabino said. "This will also strengthen the government's resolve to press him for the most information he can provide them. They could tell him, 'Yes, you can get a deal, but only if you deliver the great white whale who is Steven A. Cohen.'"

Cohen hasn't been charged with a crime.

Martoma, a former fund manager at SAC's CR Intrinsic unit, is accused of using inside information on clinical trials of an Alzheimer's disease drug to earn a profit and avoid losses for a combined benefit of at least $276 million. Martoma has pleaded not guilty.

A spokesman for SAC declined to comment on the verdict.

Steinberg showed no reaction as the verdict was announced. He was allowed to remain seated, having earlier suffered what the judge called a "dizzy spell" when the jury initially entered the courtroom.

U.S. District Judge Richard Sullivan had excused the jurors and asked that an ambulance be called. Steinberg recovered after slumping down in his chair, telling the judge he was OK. He then walked over to the judge's robing room.

"He fainted?" Sullivan asked defense lawyer Barry Berke.

"He had a seizure of some sort," Berke responded.

Sullivan said a courthouse nurse had examined Steinberg and said his blood pressure was normal. The jury returned and delivered its verdict.