Mathew Martoma, a former SAC Capital portfolio manager, arrives at federal court, Thursday, Feb. 6, 2014 in New York. The former SAC Capital Advisors portfolio manager was convicted Thursday of helping his company earn more than a quarter billion dollars illegally through trades based on secrets about the testing of a potential breakthrough Alzheimer's drug. (AP Photo/Mark Lennihan)

NEW YORK (AP) — A former SAC Capital Advisors portfolio manager was convicted Thursday of helping the company owned by billionaire Steven A. Cohen earn more than a quarter-billion dollars illegally through trades based on secrets about the testing of a potential breakthrough Alzheimer's drug.

The verdict capped a monthlong trial that featured testimony from two prominent doctors who confessed to spilling secrets to Mathew Martoma during paid consultations in the summer of 2008.

Martoma was expressionless as the jury forewoman announced he was guilty of two counts of securities fraud and conspiracy to commit securities fraud. Tears streamed down the face of his wife, Rosemary, whose hands were folded on her yellow dress. No sentencing date was set.

When prosecutors announced the case in November 2012, they said it may be the most lucrative insider trading scheme of all time.

The trial also put a spotlight on Cohen, showing he had a 20-minute phone call with Martoma a day before the Stamford, Conn.-based firm began selling a large position in pharmaceutical stocks that enabled what prosecutors said were mammoth illegal profits.

Martoma is the eighth portfolio manager or research analyst at SAC Capital to be convicted or plead guilty to criminal charges in an insider trading case. Despite his conviction, prosecutors appeared no closer to what his lawyer claimed during trial was their chief goal: to prosecute Cohen. Prosecutors, in a press release on the verdict, declined to even name Cohen, referencing him only as the "SAC Owner."

Cohen has not been criminally charged, but the Securities and Exchange Commission has accused him in a civil action of failing to prevent insider trading at the company, which he founded in 1992. He has disputed the allegations.

SAC Capital pleaded guilty in November to fraud charges and agreed to pay $1.8 billion to settle charges that it allowed, if not encouraged, insider trading for more than a decade.

Martoma attorney Richard Strassberg said after the verdict they were disappointed and planned to appeal. Jurors declined to comment outside the Manhattan courthouse shortly before Martoma descended its long staircase, tightly clutching his wife's hand.

In a statement, U.S. Attorney Preet Bharara noted Martoma was the 79th person convicted in a stream of insider trading cases over the last four years. He compared Martoma's actions to buying an answer sheet before an exam.

"As the jury unanimously found, Mathew Martoma cultivated and purchased the confidence of doctors with secret knowledge of an experimental Alzheimer's drug and used it to engage in illegal insider trading," he said. "In the short run, cheating may have been profitable for Martoma, but in the end, it made him a convicted felon."

The verdict came just weeks after another jury convicted former SAC Capital portfolio manager Michael Steinberg on insider trading charges.

During closings, Strassberg said his client was victimized by the testimony of doctors who traded their credibility for plea deals that left them beholden to the government. He said the doctors learned "just how frighteningly scary it can be if you get in the way of a government investigation that's targeting someone like Steve Cohen."

Sidney Gilman, a former professor of neurology at the University of Michigan Medical School, testified he gave Martoma secret results of the drug trial sponsored by drug makers Elan Corp. and Wyeth nearly two weeks before they were publicly announced.

Gilman, once one of the world's top Alzheimer's experts, said he was charmed by Martoma, of Boca Raton, Fla., who seemed more knowledgeable about his work than hundreds of other financial professionals who paid Gilman more than $1 million over several years for consultations.

Assistant U.S. Attorney Arlo Devlin-Brown told the jury that after the doctor showed Martoma the test results in one of 43 consultations the pair had, Martoma sent Cohen an early morning email asking: "Is there a good time to catch up with you this morning? It's important." A half-hour later, they spoke for 20 minutes on the phone.

The next day, Devlin-Brown said, Martoma and SAC Capital began selling all their shares in Elan and Wyeth and building a short position that would make millions of dollars when the stocks of both companies plummeted following the public announcement of the drug trial's results. The government said the trades on both ends earned $275 million in profits, enough to score a $9.3 million bonus for Martoma.

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