Prosecutors say a 79-year-old former New York accounting firm executive who did work for some of Bernard Madoff's most important longtime clients has earned leniency by cooperating.

Prosecutors said in a written submission late Thursday that Paul Konigsberg formally began cooperating last year and revealed damaging information about clients he had worked with closely for years. They noted that his links to Madoff had led to the sale of his business and his name being stripped from its title.

They said his cooperation supplemented evidence of how Madoff employees aided his fraud and that it helped the government assess the culpability of major Madoff clients who reaped tremendous profits.

In a separate submission, defense lawyers highlighted Konigsberg's longtime charity work, saying he deserves no prison time.