Bernard Lawrence "Bernie" Madoff (pronounced /ˈmeɪdɒf/; born April 29, 1938) is the former Chairman of the NASDAQ stock exchange and the admitted operator of the Ponzi scheme that might be "the largest investment fraud in Wall Street history".

In March 2009, Madoff pleaded guilty to 11 felonies and admitted to turning his wealth management business into a massive Ponzi scheme that defrauded thousands of investors of billions of dollars. Madoff said he began the Ponzi scheme in the early 1990s. However, federal investigators believe the fraud began as early as the 1980s, and the investment operation may never have been legitimate. The amount missing from client accounts, including fabricated gains, was almost $65 billion. The court appointed trustee estimated actual losses to investors of $18 billion. On June 29, 2009, he was sentenced to 150 years in prison, the maximum allowed.

Madoff founded the Wall Street firm Bernard L. Madoff Investment Securities LLC in 1960, and was its chairman until his arrest on December 11, 2008. The firm was one of the top market maker businesses on Wall Street, which bypassed "specialist" firms by directly executing orders over the counter from retail brokers.