| Ophthalmic Imaging Systems (OISI) OTCBB - OTC (Over-The-Counter) Bulletin Board | |
| OrganiTECH USA, Inc. (ORGT) OTCBB - OTC (Over-The-Counter) Bulletin Board | |
| Ottawa Savings Bancorp Inc (OTTW) OTCBB - OTC (Over-The-Counter) Bulletin Board | |
| Otter Tail Corporation (OTTRO) OTCBB - OTC (Over-The-Counter) Bulletin Board | |
| Odisha Cement Limited (DALBHARAT) NSE - National Stock Exchange of India | |
| Oriental Aromatics Limited (OAL) NSE - National Stock Exchange of India | |
| One Point One Solutions Limited (ONEPOINT) NSE - National Stock Exchange of India | |
| Oaktree Specialty Lending Corporation (OCSLL) NASDAQ - National Association of Securities Dealers Automated Quotations | |
| Ocugen, Inc. (OCGN) NASDAQ - National Association of Securities Dealers Automated Quotations | |
| Odonate Therapeutics, Inc. (ODT) NASDAQ - National Association of Securities Dealers Automated Quotations | |
| Office Properties Income Trust (OPI) NASDAQ - National Association of Securities Dealers Automated Quotations | |
| Office Properties Income Trust (OPINI) NASDAQ - National Association of Securities Dealers Automated Quotations | |
| OFS Capital Corporation (OFSSL) NASDAQ - National Association of Securities Dealers Automated Quotations | |
| OFS Capital Corporation (OFSSZ) NASDAQ - National Association of Securities Dealers Automated Quotations | |
| OFS Credit Company, Inc. (OCCI) NASDAQ - National Association of Securities Dealers Automated Quotations | |