| 馬名 | 父 | 母 | 生年 |
|---|---|---|---|
| Okley | Green Means Go | Open Secrets | 2002 |
| Obvious | Green Means Go | Open Secrets | 2003 |
| Open Chance | American Chance | Open Secrets | 2004 |
| オジャグワ | Pure Prize | Open Secrets | 2005 |
| Oppenheimer | Matty G | Open Secrets | 2006 |
| Opazzo | Brancusi | Open Secrets | 2008 |
| Opa Locka | Orpen | Open Secrets | 2009 |
| Opa Opa | Orpen | Open Secrets | 2010 |
| Opalele | Orpen | Open Secrets | 2011 |
| Oppositionist | Pure Prize | Open Secrets | 2012 |
| Openthegate | Cityscape | Open Secrets | 2015 |
| Oppitz | Exchange Rate | Open Secrets | 2016 |
| Opima | West by West | Open Secrets | 2017 |
| Open Mast | West by West | Open Secrets | 2019 |
| Happy Secrets | Hi Happy | Open Secrets | 2021 |