Mark Lawrence Epstein, nicknamed "Puggy", is an American property developer and real estate investor. The brother of convicted sex offender and financier Jeffrey Epstein, he has been active in real estate since the 1990s, founding and leading several companies, including Ossa Properties and Dara Partners. He also founded a silkscreen printing studio and a yacht charter service. Epstein is a 1976 graduate of Cooper Union's School of Art, and has been involved in philanthropy, serving on the boards of several nonprofits and as a chair of the Cooper Union board of trustees from 2009 to 2015.