Stephen Ongpin Fine Art counts among its clients private collectors in the UK, Europe and America, as well as a number of museums. Drawings have been acquired from SOFA by the following institutions:

Van Gogh Museum, Amsterdam
Ulster Museum, Belfast
Birmingham Museum of Art, Birmingham, Alabama
Museum of Fine Arts, Boston
Groeningemuseum, Bruges
Harvard Art Museums, Cambridge, Massachusetts
National Gallery of Australia, Canberra
Art Institute of Chicago, Chicago
Cleveland Museum of Art, Cleveland
Denver Art Museum, Denver
Musée des Beaux-Arts, Dijon
National Gallery of Scotland, Edinburgh
Städtisches Kunstinstitut, Frankfurt
Teylers Museum, Haarlem
Museum of Fine Arts, Houston
Herbert F. Johnson Museum of Art, Cornell University, Ithaca, New York
Staatliche Kunsthalle, Karlsruhe
British Museum, London
J. Paul Getty Museum, Los Angeles
The National Gallery of Victoria, Melbourne
Minneapolis Institute of Arts, Minneapolis
Museum of Fine Arts, Montreal
Yale University Art Gallery, New Haven
Dahesh Museum of Art, New York
Metropolitan Museum of Art, New York
Morgan Library and Museum, New York
Smith College Museum of Art, Northampton, Massachusetts
Snite Museum of Art, Notre Dame, Indiana
Allen Memorial Art Museum, Oberlin, Ohio
National Gallery of Canada, Ottawa
Ashmolean Museum, Oxford
Ecole Nationale Supérieure des Beaux-Arts, Paris
Fondation Custodia (Collection Frits Lugt), Paris
Musée du Louvre, Paris
Musée d’Orsay, Paris
Frances Lehman Loeb Art Center, Vassar College, Poughkeepsie, New York
Princeton University Art Museum, Princeton, New Jersey
Museum of Art, Rhode Island School of Design, Providence, Rhode Island
Virginia Museum of Fine Arts, Richmond, Virginia
Musée des Beaux-Arts, Rouen
Crocker Art Museum, Sacramento, California
The Huntington Library, San Marino, California
Nationalmuseum, Stockholm
The Art Gallery of New South Wales, Sydney
Art Gallery of Ontario, Toronto
National Gallery of Art, Washington, DC
Kunstsammlungen zu Weimar, Weimar
Delaware Art Museum, Wilmington, Delaware
Graphische Sammlung, ETH, Zurich