In the annals of hedge-fund collapses, Sylvester Stallone is among lucky investors who walked away unscathed -- or so it seemed.

In 1997, the actor invested $2.5 million in a private investment partnership called Lipper Convertibles. Four years later, with his statements showing the investment had swelled to about $3.8 million, he cashed out. Fellow actor John Cusack also walked away with big gains, as did former New York City Mayor Ed Koch and a trust fund for the children of investor Henry Kravis.

Now, they are all being sued to give money back.

What none realized, according to their lawyers, was that Lipper never made all that money. A portfolio manager had inflated profits by at least 40 percent, Lipper discovered in 2002. "We want all the money to be put back in the pool, so we can divvy it up equitably among all the partners," says Thomas Dubbs, an attorney representing the federal trustee overseeing Lipper.

(The hedge fund is unrelated to Lipper Inc., the mutual-fund data firm, which is part of Reuters Group PLC.)

In lawsuits filed in recent months in New York state court in Manhattan, the trustee, Richard Williamson, charges the investors who got out with "unjust enrichment." He wants them to return more than $100 million, including $1.3 million plus interest from Mr. Stallone alone.

Messrs. Stallone and Cusack, in court documents, say they were unaware of the fraud and didn't harm fellow investors. In an interview, Mr. Koch, who now works as an attorney at a private firm, says he intends to keep his profits, which amount to about $1 million, including interest. "It's just wrong," he says.

The battle highlights a trend emerging from the boom in hedge funds, which now control assets of more than $1 trillion for wealthy investors and institutions. In the wake of some failures, those investors who lost money are chasing those who cashed out. However, there is little precedent in terms of applying this legal argument to failed hedge funds. As a result, it remains to be seen whether the new cases have any success.

A trustee liquidating Bayou Management LLC, a failed Connecticut hedge fund, is attempting to reclaim more than $100 million from investors, including a fund called Sterling Stamos in which the owner of the New York Mets baseball team, Fred Wilpon, has a stake. In a separate matter, a Long Island family is suing several fellow investors in a bogus hedge fund called Sterling Watters. Among defendants: a former official of the Securities and Exchange Commission.

Those cases, like the Lipper case, are pending in state Supreme Court in Manhattan. Individuals who profited "should be sharing the pain," says Jeff Marwil, the federal trustee in charge of liquidating Bayou. "Our goal is to equalize in a fair and equitable fashion."

Bayou collapsed last summer after two founders revealed they had inflated profits figures and did not have the $450 million investors believed they had in the fund. The founders pleaded guilty to fraud and await sentencing. In February, Bayou filed for protection under Chapter 11 of the U.S. bankruptcy code.

Mr. Marwil has filed several lawsuits in recent months to retrieve money from investors.

Among them is UT Medical Group, a private-practice arm of University of Tennessee Health Science Center, which declined to comment on the lawsuit. Mr. Marwil is still tallying how much money was removed; others familiar with the matter estimate that as much as $250 million could be reclaimed. He says he intends to file several more lawsuits.

Unlike the Lipper cases, Mr. Marwil wants Bayou investors to return more than their profits: He also wants them to give back the money they originally put into the fund. So far, he is concentrating on investors who cashed out less than two years before he brought suit. That is the statute of limitations under bankruptcy law, though under state laws he could ultimately extend further back.

"Every payment made by the hedge fund needs to come back," he says. "We will then determine a payment scheme based on the amount of time the investor was in the fund and the losses in the fund."

Among investors who got out before the meltdown was Sterling Stamos. In early 2005, it withdrew tens of millions of dollars from Bayou, according to people close to the matter. The firm hasn't been sued, but its account has been reviewed by Mr. Marwil. An attorney for Sterling Stamos declined to comment.

The suit alleges that the money was unfairly paid out as part of the scheme by the managers to defraud investors. It is akin to Ponzi schemes, in which newcomers' money is paid to people who want to cash out, in order to create the false impression that the business is financially successful.

Similar issues surrounded Bennett Funding Group, which sought protection under bankruptcy laws in the mid-1990s, after federal securities regulators accused company officials of a scheme to cheat investors. A trustee overseeing the case, former SEC chairman Richard Breeden, liquidated Bennett, then sued thousands of investors who had cashed out. The effort recouped only a fraction of the money.

Charles Gradante, a partner in Hennessee Group, a hedge-fund consultant, is among those lauding the wave of new suits. Those who invested in Bayou on the advice of Hennessee collectively lost an estimated $20 million, he says. Ross Intelisano, a lawyer representing about 20 investors who also collectively claim to have lost $20 million in Bayou, said, "Our clients are very supportive."

The legal grounds are similar in a case filed by a Long Island family that claims to have lost about $7 million in a fund called Sterling Watters. It was launched in 1995 by a former Merrill Lynch broker named Angelo Haligiannis. He reported to investors that he was making annualized returns of 35 percent to 40 percent.

Among investors who profited was Peter Derby, who last year left the SEC where he was managing director for operations under former chairman William Donaldson. Mr. Derby had invested $1 million in 2002 and got that back, along with $185,000 in profits, when he redeemed a year later, according to records reviewed by people close to the matter.

Another investor, Jerry Drenis, contends that Mr. Derby and others were essentially paid with money stolen from others, including Mr. Drenis and his family. Mr. Drenis and his relatives collectively lost more than $7 million, he says. They are suing Mr. Derby and two dozen other investors.

"Angelo Haligiannis gave away our money to pay off other investors," says Mr. Drenis, the owner of a heating-oil business. "It's not their money to keep."

Sterling Watters, the Justice Department says, raised more than $25 million by misrepresenting its performance figures through a classic Ponzi scheme. Mr. Haligiannis vanished before his sentencing earlier this year.

Mr. Derby has filed a motion to dismiss the suit. "Even if the allegations are true -- which, of course we'd dispute if the ruling went against us -- there is no viable cause of action in which plaintiffs can recover" money, says Mr. Derby's attorney, Gary Kushner. Among other things, he says, limited partners in a corporation can't sue each other under state law.

Another defendant, Joseph Biasucci, a 68-year-old retired executive of the Teamsters union, says that he can't give back his profits. "I don't have it," he says. "I paid capital-gains taxes, and I spent the rest."

Mr. Biasucci says he found out about Sterling Watters through a lawyer in the mid-1990s and invested $50,000. He says that it ostensibly grew to about $130,000 over 10 years. He dipped in now and then, he says, to pay bills and taxes, coming out a bit ahead. Still, the paper loss was devastating, he says. "This was my retirement money."

In the Lipper case, the fund's namesake, Ken Lipper, made many connections working as a former deputy under Mayor Koch, and as the author of the novel "Wall Street."

Among numerous prominent investors was Mr. Kravis's children's trust, which court documents show made a $2.6 million investment in 1995. In 2001, the trust was paid a profit of $2.8 million.

It wasn't until two years later that Lipper sent the letter to investors saying that it had discovered that the profits had been inflated by more than $300 million. A portfolio manager, Edward Strafaci, pleaded guilty in 2004 to a federal charge of securities fraud and was sentenced to six years in prison.

Given the revised figures, the lawsuit filed last year by Mr. Williamson says, the Kravis trust should have received only $712,346. Thus, it "erroneously" received a $2.17 million windfall that "greatly exceeded the value" of its interests. The Kravis trust has filed a motion to dismiss that suit.

Mr. Cusack's Lipper investment, which totaled $300,000, was made in the mid-1990s, court documents show. In 2000, he was given $537,705, or an alleged overpayment of $166,123 plus $67,025 interest.

In an answer filed last month, a lawyer for Mr. Cusack says that "the damages alleged in the complaint were not caused by the alleged 'excess' payments to Cusack."