The trustee signed the settlement in order to

The trustee appointed to recover money stolen by the New York financier Bernard Madoff has reached a multibillion-dollar settlement with the estate of [10] a man identified as the biggest single beneficiary of the fraud. [9]It means about half the money lost in the swindle will ultimately be recouped.
    The settlement represents something of a coup for the trustee Irving Picard. After the collapse of Bernard Madoff’s investment firm in 2008, he was given the task of recovering money lost by investors, who’d unwittingly put their cash into the giant Ponzi scheme. Since then he’s launched a wave of litigation against people and businesses deemed to have profited from the fraud. Chief among them was Jeffry Picower, who was a long-term investor in Bernard Madoff s funds. Over the course of three and a half decades, he withdrew some $7bn, substantially more than his initial investment. His widow has now pledged to return every penny he received.