Augustus Bertrand "Gus" Greenbaum (1894-1958) was a Las Vegas, Nevada casino executive with ties to organized crime. A longtime associate of Meyer Lansky, Greenbaum moved to Las Vegas in the early 1940s as an investor in the El Cortez and the race wire. In 1946, he became involved in the Flamingo, and after the June 1947 murder of Benjamin "Bugsy" Siegel, he assumed control of the property along with Morris Rosen and Moe Sedway. Greenbaum turned Siegel's financial losses into a $4 million profit within a year.