Patrick T. O’Connor

Discover Greysheet, the trusted authority in rare coin and paper money pricing and market intelligence. Delivering comprehensive wholesale, retail, and auction data, along with expert analysis, Greysheet equips dealers and collectors with transparent, reliable information to confidently navigate today’s evolving numismatic marketplace.

Discover Whitman Expos, premier coin and currency conventions held annually in Baltimore. Featuring hundreds of dealers, Stack’s Bowers Galleries auctions, and educational programming, these events bring together collectors, investors, and industry leaders in a dynamic marketplace that fosters community, scholarship, and engagement.

Discover H.E. Harris, a respected name in stamp collecting offering U.S. and worldwide stamps, albums, and supplies through a convenient e-commerce platform. Designed for collectors of all levels, H.E. Harris makes philately accessible and enjoyable, with curated products, resources, and trusted tools to build and organize your collection.