FACTBOX: Madoff's "unprecedented" fraud

NEW YORK (Reuters) - Bernard Madoff pleaded guilty to 11 criminal counts of fraud that could put him in prison for the rest of his life. Prosecutors say the alleged crimes spanned more than 20 years.

The counts include:

* Securities fraud, investment adviser fraud, mail fraud, wire fraud, three counts of money laundering, false statements, perjury, false filings with the U.S. Securities and Exchange Commission, and theft from an employee benefit plan.

* U.S. prosecutors say there is no plea agreement between Madoff and the government, indicating he is unwilling to admit there was a conspiracy.

* The prosecutors say "the size and scope of Mr. Madoff's fraud are unprecedented" and their investigation is continuing.

* The government says Madoff faces up to 150 years in prison if convicted of all charges.

* The government says Madoff is also subject to mandatory restitution payments, fines and forfeiture of ill-gotten gains. The forfeiture sought by the government is more than $170 billion, a figure that has been challenged by Madoff's lawyers.

* The government says Madoff's investment business had about 4,800 client accounts as of November 30. 2008.

* The investment business issued statements for November 2008 reporting accounts held a total of $64.8 billion. In reality, the business "held only a small fraction" of that balance for clients, according to the government.

* Prosecutors contend the alleged scheme lasted from "at least" the 1980s, and Madoff hired numerous employees "with little or no prior pertinent training or experience in the securities industry" to communicate with his investment clients and "generate false and fraudulent documents."

(Reporting by Martha Graybow and Paul Thomasch; Editing by Brian Moss)