Mark Lawrence Epstein is a New York-based real estate developer, former artist, and the younger brother of financier and sex offender Jeffrey Epstein. He began his career in the arts before transitioning to real estate investment in the 1990s, founding and serving as president of Ossa Properties, Inc., a property management firm. Mark has managed properties linked to his brother's estate and family holdings, including purchasing an apartment building from Jeffrey and involvement in entities tied to his brother's financial network. He has held influential positions, such as a tenure on the Board of Trustees at Cooper Union, where he served as chairman. Gaining significant public attention after Jeffrey's 2019 arrest and death, Mark is a beneficiary of his brother's estate and has faced questions about their financial ties, including legal matters related to the estate. Throughout his career, he has maintained a lower profile than his brother and attempted to distance his business activities from Jeffrey's criminal history, asserting their primary relationship was that of landlord and tenant. He is also a father, sharing the same mother as his brother.