Barry Greenhouse is a former executive at the firm Bernard L. Madoff Investment Securities (BLMIS), known primarily for his role as a whistleblower in the Madoff scandal. During his long career within the firm, Greenhouse oversaw the market-making and proprietary trading operations, the firm's legitimate and separate arm from its fraudulent investment management division. Suspecting financial irregularities, he actively collaborated with financial analyst Harry Markopolos, providing crucial information and corroborating the complaints that Markopolos submitted for years, without success, to the Securities and Exchange Commission (SEC). His contribution was instrumental in exposing the scale of the Ponzi scheme. For his courage and integrity, in 2011 he received, along with others, the "Whistleblower of the Year" award from the Taxpayers Against Fraud Education Fund.