Epstein was teaching calculus and physics at the Dalton School in Manhattan between 1973 to 1975. In 1976, Epstein started work as an options trader (a job where stock brokers can buy or sell shares at an agreed price at a later date) at Bear Stearns, where he advised very rich people on financial strategies relating to taxes. As he was shown to be a successful worker during his financial career, Epstein became promoted to a limited partner (a job that manages money within a company) at Bear Stearns in 1980.