| Ookami Ltd (OOK) ASX - Australian Securities Exchange | |
| Opthea Ltd (OPT) ASX - Australian Securities Exchange | |
| Orion Health Group Ltd (OHE) ASX - Australian Securities Exchange | |
| Otherlevels Holdings Ltd (OLV) ASX - Australian Securities Exchange | |
| Over The Wire Holdings Ltd (OTW) ASX - Australian Securities Exchange | |
| oOh!Media Ltd (OML) ASX - Australian Securities Exchange | |
| Obsido Socimi SA (YOSO) BME - Bolsa de Madrid Exchange | |
| Oryzon Genomics SA (ORY) BME - Bolsa de Madrid Exchange | |
| Oakbay Resources and Energy Ltd (ORL) JSE - Johannesburg Stock Exchange | |
| OAT Agrio Co Ltd (4979) TYO - Tokyo Stock Exchange | |
| Ohki Healthcare Holdings Co Ltd (3417) TYO - Tokyo Stock Exchange | |
| Open Door Inc (3926) TYO - Tokyo Stock Exchange | |
| Oceanside Capital Corp. (OCE) CNSX - Canadian Securities Exchange | |
| Ouro Fino Saude Animal Participacoes SA (OFSA3) BVMF - Bovespa Stock Exchange | |
| OMV (OMV) SWX - SIX Swiss Exchange | |