David Israel Margolis (January 24, 1930 – December 13, 2008) was an American industrialist who served as president and chairman of Colt Industries, who was a confidant of former Mayor of New York City Ed Koch. Margolis was born in the Bronx on January 24, 1930. He attended the City College of New York where he received bachelor's and master's degrees in economics. After graduating, he became the assistant treasurer at Raytheon and treasurer of International Telephone & Telegraph (ITT). Margolis met Harold Geneen at a Boston company in the 1950s and followed him to ITT.