A spokeswoman for the U.S. attorney in the Southern District of New York, which is overseeing the case, declined to comment. An attorney for Mr. Makov couldn't be reached.

Mr. Makov would be the second person to plead guilty in the case. He is one of two people who didn't work at KPMG, but his guilty plea should give the government's case a boost. Federal prosecutors indicted 19 individuals on tax-fraud charges in 2005 for their roles in the sale and marketing of bogus shelters.

The government billed the case as the largest tax-fraud case in U.S. history. But last month the federal judge overseeing the case dismissed the charges against 13 of the defendants after finding that prosecutors violated their constitutional rights by pressuring KPMG to cut off payment of their legal fees.

The government denies using any undue influence in KPMG's legal fee decision and plans to appeal. If the judge's ruling is reversed, the 13 former defendants could be indicted again.

For now, opening statements in the trial against the remaining defendants is scheduled for Oct. 16. Two of the defendants -- John Larson and Robert Pfaff -- left KPMG and formed Presidio Advisory Services, where Mr. Makov worked. Prosecutors allege the firm earned fees helping to sell bogus tax shelters. The other defendants are R.J. Ruble, a former law partner at Sidley Austin LLP, and David Greenberg, a former partner at KPMG.

Each of the remaining defendants has pleaded not guilty and is fighting the charges.

KPMG admitted to criminal wrongdoing but avoided indictment that could have put the tax giant out of business. Instead, the firm reached a deferred-prosecution agreement that included a $456 million penalty. Last week, the federal court in Manhattan received $150,000 from Mr. Makov as part of a bail modification agreement that allows him to travel to Israel.