American businessman and hedge fund manager Stephen Mandel has an estimated net worth of $2.5 billion as of April 2016 according to Forbes. He is known to be the founder of the hedge fund firm Lone Pine Capital.

Of Jewish ancestry, Stephen Mandel Jr. was born on March 12, 1956. He is a graduate of Phillips Exeter Academy and Dartmouth College. Shortly, he went to Harvard University where he completed his MBA. He is currently married to Susan Joy Zadek with whom he has three children.

Prior to the founding of Lone Pine Capital, Stephen Mandel has worked as a senior consultant at Mars & Co. Eventually, he started working for Goldman, Sachs & Co. He worked for the company until 1990. He was then hired at Tiger Management as a consumer analyst and eventually became the firm's managing director. In 1997, he left Tiger Management and formed his own hedge fund firm Lone Pine Capital.

A well-known philanthropist, Mandel is the founder of two charitable organizations, Zoom Foundation which focuses on environment and education causes, and Lone Pine Foundation that seeks to improve the quality of education in New York City, London, New York, Hong Kong, Fairfield County, Connecticut and Westchester County.