David M. Einhorn is an American investor, hedge fund manager, and amateur poker player, best known as the founder and president of Greenlight Capital, a long-short value-oriented hedge fund launched in 1996 with $1 million under management. Born on November 20, 1968, in Demarest, New Jersey, to a Jewish family—parents Nancy and Stephen Einhorn, with Stephen founding Einhorn & Associates consulting firm and Capital Midwest Fund—Einhorn moved to Wisconsin at age seven, graduating from Nicolet High School in Glendale in 1987. He excelled at Cornell University, earning a B.A. in government summa cum laude from the College of Arts and Sciences in 1991, where he was a Sigma Alpha Epsilon fraternity member, Phi Beta Kappa, and interned at the SEC. Einhorn's career began in investment banking at Donaldson, Lufkin & Jenrette, followed by hedge fund research at Siegler, Collery & Co., before co-founding Greenlight with Jeff Keswin. He gained fame for high-profile short positions, including Lehman Brothers in 2008 (publicized at a conference highlighting accounting issues), Green Mountain Coffee Roasters, and activism against Apple and Microsoft; he chairs Greenlight Capital Re (NASDAQ: GLRE) and serves on boards for Hillel, Michael J. Fox Foundation for Parkinson’s Research, and Robin Hood Foundation. Einhorn married Cheryl Strauss, a Cornell alumna and financial reporter, in 1993; they divorced in 2017 and have three children. He resides in Westchester County, New York, and has pursued philanthropy, including a failed 2011 bid as preferred partner for the New York Mets. An avid poker player, Einhorn has competed in events like the Triton Poker Invitational. His influence, dubbed the 'Einhorn Effect,' stems from market-moving commentary, though Greenlight has faced challenges in recent years amid value investing headwinds. He collaborated professionally with Paul Singer and remains active in critiquing markets, such as AI spending splurges.