| Symbol | Name | Country | Exchange |
|---|---|---|---|
| OMCL | Omnicell, Inc. | US | NASDAQ |
| OMED | Jayamas Medica Industri | ID | JK |
| OMI | Owens & Minor, Inc. | US | NYSE |
| ONCO3 | Oncoclinicas do Brasil | BR | SA |
| ONCSM | Oncosem Onkolojik Sistemler Sanayi ve Ticaret A.S. | TR | IS |
| ONE | Oneview Healthcare PLC | AU | ASX |
| ONEM | 1Life Healthcare, Inc. | US | NASDAQ |
| OPA0 | ORPEA UNSP.ADR/1/5 | DE | F |
| OPRX | OptimizeRx Corporation | US | NASDAQ |
| OPSSF | Opsens Inc | US | OTC |
| ORP | Orpea SA | FR | PA |
| OSAAW | ProSomnus Inc. Warrant | US | US |
| OSH | Oak Street Health, Inc. | US | NYSE |
| OSSR | Ossur HF | DK | CO |
| OSUR | OraSure Technologies, Inc. | US | NASDAQ |
| OTRK | Ontrak, Inc. | US | NASDAQ |
| OTX | MEDINEX LIMITED | SG | SG |
| OVN | Oventus Medical Ltd | AU | ASX |
| P750 | PHARMACOLOG I UPPSALA B | DE | F |
| PACS | PACS Group, Inc. | US | US |