Mark Epstein, born in 1953, is an American real estate developer and the younger brother of Jeffrey Epstein. A former artist who transitioned into New York City real estate, Mark has owned and managed multiple properties through his company Ossa Properties, including buildings at 301 East 66th Street that were repeatedly connected to his brother's network. While Mark has not been accused of crimes related to Jeffrey's sex trafficking operation, his property holdings and financial connections have made him a recurring figure in investigative reporting on the Epstein network. He has publicly questioned the official narrative of his brother's death and recently claimed that Jeffrey Epstein possessed compromising information about President Donald Trump.
Mark Epstein founded Ossa Properties, which owns and manages multiple apartment buildings in Manhattan. His most notable property holding is 301 East 66th Street, a building that has turned up repeatedly in sex trafficking lawsuits against Jeffrey Epstein. Survivor testimony and property records show the building was used to house associates, models, and visitors connected to Jeffrey's operations. The confusing similarity between Mark's company name "Ossa Properties" and Jeffrey's shell company "Ossa Corp." has complicated property searches and raised questions about whether apartments controlled by Mark's company were accessed or used by Jeffrey. Mark claims semi-retirement at age 39, though the source of his wealth remains unclear. He offered a Florida condo as bail collateral for Jeffrey in 2019.
In a July 2025 interview, Mark stated: "They both came out of the autopsy room and they said they couldn't call it a suicide because it looked too much like a homicide." In November 2025, Mark made public claims that Jeffrey Epstein possessed compromising information about Donald Trump, stating: "He didn't tell me what he knew, but Jeffrey definitely had dirt on Trump." Mark also alleged that the Epstein files being prepared for public release were being "cleaned," with names of Republican figures removed from internal emails.
Mark Epstein's significance in the broader Epstein case lies less in direct allegations against him than in his property footprint, which served as logistical infrastructure for Jeffrey's network. His real estate holdings have drawn scrutiny in asset-tracing efforts, and the overlap between his properties and Jeffrey's operations raises questions about the difficulty of separating family loyalty from asset overlap in mapping Epstein's financial empire. He also founded Saint Model and Talent agency in 2005, co-founded King Graphic Technologies Inc., and served as former board member and vice chairman of the Humpty Dumpty Institute.
Sources
The Daily Beast; Business Insider; Yahoo News Singapore; Anadolu Agency; People Magazine; Yahoo News Canada; Yahoo UK News; Primal Information.