Plotkin pleaded guilty to conspiracy to commit securities fraud and eight counts of insider trading.

On Friday, a Federal judge in Virginia made public Mr. Melcher's guilty plea to charges of conspiracy to commit securities and tax fraud stemming from the matter.

"Yeah, I'm guilty," said Shapiro, whose plea to counts of securities fraud, conspiracy to commit securities fraud and money laundering resulted in a 20-year federal prison sentence.

Last month, the S.E.C. charged that Drexel, four executives and others had committed several securities law violations, including defrauding clients, illegal insider trading and stock manipulation.

A stock promoter who prosecutors say tried to have his accountant beaten up pleaded guilty yesterday in Las Vegas, Nev., to charges of money laundering and conspiracy to commit securities and bank fraud.

This year, David A. Thatcher, the former president of Critical Path Inc., an e-mail provider based in San Francisco, pleaded guilty to conspiracy to commit securities fraud and agreed to pay a $110,000 fine.

Mr. Gleeman pleaded guilty to conspiracy to commit securities fraud and one count of wire fraud.

Forbes was found guilty of conspiracy to commit securities fraud and two counts of making false statements at a third trial on October 31, 2006.

It said the defendants "knowingly acted together to manipulate the market price of AremisSoft common stock by creating and disseminating false and misleading information," thus committing securities fraud.

The long-awaited charges included conspiracy to commit securities, mail and wire fraud and three counts of having committed securities fraud.