From his German roots, Aby Rosen co-founded RFR Holding in 1991 with Michael Fuchs, building a portfolio valued at $18-19 billion that includes Manhattan icons like the Seagram Building—recently refinanced for $1.2 billion—and Lever House. In early 2025, RFR orchestrated a $160 million recapitalization of 475 Fifth Avenue, averting foreclosure and underscoring Rosen's adeptness at navigating market turbulence alongside extensions on loans for 17 State Street and 150 East 72nd Street. Miami ties RFR to South Florida via ownership of the high-end W South Beach, blending seamlessly with holdings in Las Vegas and Tel Aviv. An avid collector of postwar art with over 800 pieces including numerous Andy Warhols, Rosen integrates bold exhibits into properties like Lever House. As sons Gaby and Charlie assume greater leadership, RFR shifts toward a collaborative executive structure while retaining its private agility.