| OTGAW | OTG Acquisition Corp. I | — | — | — | 0 |
| OTIS | Otis Worldwide Corporation | Industrials | $25.4B | — | 0 |
| OTTR | Otter Tail Corporation | Industrials | $3.7B | — | 0 |
| OBCKF | Ottobock SE & Co. KGaA/ADR | — | — | — | 0 |
| OBAI | Our Bond, Inc. | Technology | $3.2M | — | 0 |
| OURA | Oura Inc. | — | — | — | 0 |
| OUST | Ouster, Inc. | Technology | $3.0B | — | 0 |
| OCGSF | Outcrop Silver & Gold Corporation | Basic Materials | $114M | — | 0 |
| POWWP | Outdoor Holding Company - 8.75% Series A Cumulative Redeemable Perpetual Preferred Stock | Industrials | $248M | — | 0 |
| ODRS | Outdoor Specialty Products, Inc. | — | — | — | 0 |
| OUT | Outfront Media Inc. | Real Estate | $4.9B | — | 0 |
| OTLK | Outlook Therapeutics, Inc. | Healthcare | $123M | — | 0 |
| OM | Outset Medical, Inc. | Healthcare | $58.0M | — | 0 |
| OVID | Ovid Therapeutics Inc. | Healthcare | $466M | — | 0 |
| OVV | Ovintiv Inc. | Energy | $16.7B | — | 0 |
| OC | Owens Corning | Basic Materials | $9.7B | — | 0 |
| OWLT | Owlet, Inc. | Healthcare | $91.7M | — | 0 |
| OXBRW | Oxbridge Re Holdings Limited | Financial Services | $15.5M | — | 0 |
| OXM | Oxford Industries, Inc. | Consumer Cyclical | $389M | — | 0 |
| OXLCL | Oxford Lane Capital Corp. 6.75% Notes due 2031 | Financial Services | $11.6B | — | 0 |
| OXSQH | Oxford Square Capital Corp. | Financial Services | $164M | — | 0 |
| OBAWW | Oxley Bridge Acquisition Limited | Financial Services | $349M | — | 0 |
| OYCG | Oyocar Group Inc. | — | — | — | 0 |
| OYSEU | Oyster Enterprises II Acquisition Corp | Financial Services | $368M | — | 0 |
| OZVN | OZ Vision Inc. | — | — | — | 0 |