Speculation is rampant that Bernard L. Madoff, the once-heralded New York investment guru now known as the mastermind of the world's largest-ever Ponzi scheme, will plead guilty and accept some type of plea agreement next week.

The 70-year-old former NASDAQ chairman today waived his right to a formal grand jury review of the charges he is facing. That move is typically a precursor to a plea deal, which is under negotiation between Madoff and federal prosecutors since his Dec. 11 arrest.

Next Thursday, Madoff will be formally arraigned and enter a plea. Jacob Frenkel, a former Securities and Exchange Commission attorney, told Bloomberg that he expects Madoff will plead guilty.

Wall Street Journal Law Blog reporter Amir Efrati writes, however, that "no plea agreement is expected soon":

At a hearing next Thursday, the government is expected to file the information, which will lay out allegations against Mr. Madoff and list numerous criminal charges against him. At that point, Madoff may say that he plans to plead guilty to the charges or that he would like to go to trial.

Efrati reports that it's unclear how cooperative Madoff has been during the criminal investigation. He has told prosecutors he acted alone in committing the fraud, but the government believes other individuals were likely involved, according to a person familiar with the matter.

If he pleads guilty at the hearing, Madoff might be jailed to await sentencing and might be asked questions related to the Ponzi scheme. A trustee assigned to find Madoff's assets has discovered $900 million and Madoff himself has offered to give up properties in Palm Beach, Fla., and Antibes, France, along with a number of boats and vehicles.

But Madoff's attorneys have also argued that his wife, Ruth, is the sole owner of the couple's $7 million Manhattan apartment (where Madoff is under house arrest), $45 million in bonds and $17 million in cash.