Disgraced financier Bernard Madoff will not appeal his 150-year sentence for a fraud that unraveled overnight last December when Madoff confessed to his sons that nearly $65 billion he promised investors was safe was actually only worth a few hundred million dollars.

“We won’t be appealing the sentence,” Madoff’s lawyer, Ira Sorkin, said Thursday. He declined to say why the decision was made. Rebekah Carmichael, a prosecutor’s spokeswoman, declined to comment.