New York ? Disgraced financier Bernard Madoff should receive a 150-year sentence for orchestrating perhaps the largest financial swindle in history, federal prosecutors said in court papers Friday.

“The sheer scale of the fraud calls for severe punishment,” the prosecutors wrote in response to a defense motion seeking lighter punishment.

Madoff, 71, is due to be sentenced Monday after pleading guilty in March to charges that his exclusive investment advisory business was actually a massive Ponzi scheme.

Federal sentencing guidelines allow for the 150-year term, prosecutors said. Any lesser sentence, they added, should still be long enough to send a forceful message and “assure that Madoff will remain in prison for life.”

The government’s papers quoted from letters to U.S. District Judge Denny Chin written by victims of the scheme who are suffering severe hardships.

Madoff “ruined lives,” one letter said. “He deserves no mercy.”