Bernard Lawrence Madoff (MAY-dawf; April 29, 1938 – April 14, 2021) was an American financial criminal and financier who was the admitted mastermind of the largest known Ponzi scheme in history, worth an estimated $65 billion. He was at one time chairman of the Nasdaq stock exchange. His firm had two basic units: a stock brokerage and an asset management business; the Ponzi scheme was centered in the asset management business.