Peter Madoff spoke briefly Thursday and less emotionally than in June, saying: "I am deeply ashamed of my conduct and have tried to atone by pleading guilty and have agreed to forfeit all of my present and future assets."
He added: "I am profoundly sorry that my failures let many people down, including my loved ones."
Two investors, among 40 who wrote victim impact statements, spoke during the proceeding, each describing the financial ruins of their extended family.
Investor Michael T. De Vita, 62, also called for truth, saying he believed "it to be physically impossible for a single person to carry out such a gargantuan task all by himself."
De Vita said investors "have waited four years for others to accept responsibility for this massive crime. We are still waiting for that today."
"All of this was preventable if only one person was willing to do the right thing and stop this in its tracks years ago. Peter Madoff could have been that person," he said.
Nissenbaum said Peter Madoff was part of his brother's fraud for more than 30 years and he should serve the same amount of time in prison.
The judge noted that 10 years was the maximum sentence allowed by the charges to which Madoff had pled and repeatedly urged Madoff to relieve the pain of investors by revealing more about the Madoff business.
"I challenge you to be honest about all that you have done and all that you have seen. In other words, all that you know," she said.
The magnitude of the damage done by the Madoffs cannot be underestimated, she said.
"Trust in financial institutions, thousands of individual lives and numerous charitable organizations have been blown apart," she said.
Assistant U.S. Attorney Lisa Baroni said it would have been easy for Peter Madoff to blow the whistle if he had even minimally carried out his duties. Instead, she said, he even teamed up with his brother to distribute the remaining $300 million in the company's accounts to family, friends and favored clients before the FBI put an end to that scheme by arresting his brother.
The sentencing comes four years and a week after Bernard Madoff first revealed the fraud, which occurred as the former NASDAQ chairman built a reputation for delivering unparalleled investment results, even in bad times. The revelation came only days after the business sent out statements that made investors think their investments had grown to a total of more than $65 billion.
Peter Madoff said at his plea that he had no idea his brother was running a massive Ponzi scheme, paying off longtime investors at times with money from newer investors.
"My family was torn apart as a result of my brother's atrocious conduct," he said. "I was reviled by strangers as well as friends who assumed that I knew about the Ponzi scheme."
Peter Madoff, who joined his brother's firm after graduating from Fordham Law School in 1970, has been free on $5 million bail after he agreed to surrender all assets.