| Name | Country | Region | Address |
|---|---|---|---|
| William Askins (USA) | |||
| William F. Lynn | USA | ||
| William M. Backer Revocable Trust | USA | ||
| Williamson Racing, LLC | USA | ||
| Willy Kottek | Germany | ||
| Willy Lockhart, Lockhart Quintana Hermanos | Uruguay | ||
| Wilma Mooij-Jan der Wal | Netherlands | ||
| Wilmsdorf | Germany | ||
| Wilnjusskij, ks | Lithuania | ||
| Wimberley Bloodstock, LLC | USA |