WASHINGTON — While the federal government has garnered its biggest victory from the business scandals of recent years with the conviction of former Enron Corp. chiefs Kenneth Lay and Jeffrey Skilling, prosecutors may have their sights on a new crop of potential targets.

Newer cases of accounting fraud could bring a fresh set of company executives into prosecutors' sights, and a probe of at least 15 companies for the timing of stock option grants to their leaders is widening. This week's revelations concerning Fannie Mae — regulators said the mortgage giant manipulated accounting so that senior executives could collect millions in bonuses — were a reminder that there's more out there.

"Corporate corruption is not over," Sen. Carl Levin, D-Mich., who investigated many facets of the Enron tangle, declared yesterday.

A four-month-long fraud and conspiracy trial brought guilty verdicts Thursday against Lay and Skilling, who could receive double-digit prison sentences. The government's victory capped a 4 1/2-year investigation that garnered 16 guilty pleas from exEnron executives. It was the endgame to a scandal that wiped out more than $60 billion in company market value, nearly $2.1 billion in employees' retirement savings, 5,600 jobs and billions in pension fund holdings across the country.

"The victory, and the visibility of the victory, is going to encourage prosecutors to take on more cases that involve very complex financial dealings," said James Cox, a professor at Duke University who specializes in securities law.

For individual executives, there could be more handcuffs and perp walks on the horizon. "Your risks of facing serious criminal and civil sanctions are going up with every successful prosecution by the government," Cox said.

The Sarbanes-Oxley anti-fraud law born of the 2002 wave of business scandals requires CEOs and chief financial officers to certify in sworn written statements the accuracy of the company's financial results — with possible prison terms for signing statements they knew to be false.

Regarding Fannie Mae, the Securities and Exchange Commission and the Office of Federal Housing Enterprise Oversight are looking at the roles of several current and former executives — including ousted Chairman Franklin Raines — in the accounting failures and whether they should be forced to return millions in compensation. A criminal investigation of the company by the Justice Department is continuing.

Raines' attorney, Robert Barnett, said this week that Raines "never authorized, encouraged or was aware of violations" of accounting rules at the company, formally known as the Federal National Mortgage Corp.

The widening investigation of companies for timing of stock option grants to executives is being conducted by the SEC and federal prosecutors in New York. The companies — the biggest so far is UnitedHealth Group Inc. — are being examined to determine whether they boosted executives' payoff from stock options by backdating the grants to coincide with a point where corresponding stock prices had dropped to lows.

At least 15 companies have received subpoenas. "I would not be surprised to see it double or even triple in the coming months," said Bruce Vanyo, a securities lawyer at Katten Muchin Rosenman in Los Angeles.

The SEC is also conducting an inquiry into pension fund accounting at several major companies to determine whether they are using the funds to manipulate earnings. They include General Motors Corp., Ford Motor Co., Delphi Corp., Boeing Co., Navistar International Corp. and Northwest Airlines Corp.

The agency says it's examining whether changes in pension plans can create so-called "cookie jar" reserves that could be dipped into to bolster revenue in less profitable times. For example, if a company forecasts too rosy a rate of return on investments used to fund the plans, it doesn't have to set aside as much money to cover the liabilities. The extra money could be used to inflate earnings.