| OAK 1890266 · TMA1143957 | Operis Group Plc | 9 Electronics | Registered | 2022 |
| OKE 1815926 · TMA1163861 | OKE Group GmbH | 6 Metal9 Electronics10 Medical+10 | Registered | 2023 |
| OASE 1665338 · TMA1034869 | OASE GmbH | 1 Chemicals6 Metal7 Machines+14 | Registered | 2019 |
| OAK 1591128 · TMA854103 | Bath & Body Works Brand Management, Inc. | 3 Cosmetics4 Oils8 Hand+1 | Registered | 2013 |
| OASE 1520815 · TMA873601 | Owner not shown | 1 Chemicals42 Science45 Legal | Registered | 2014 |
| OAKS 1195526 · TMA630213 · design | BRAMPTON BRICK LIMITED/ BRIQUE BRAMPTON LIMITÉE | 19 Building | Registered | 2005 |
| OAK 0896813 · TMA525829 · design | PARRISH & HEIMBECKER, LIMITED | 30 Coffee | Registered | 2000 |
| OAK 0896812 · TMA525828 | PARRISH & HEIMBECKER, LIMITED | 30 Coffee | Registered | 2000 |
| OAK 2328931 | Owner not listed | 6 Metal11 Lighting21 Housewares | Pending | 2024 |
| OASE 2252843 · design | Owner not listed | 1 Chemicals5 Pharmaceuticals6 Metal+17 | Pending | 2022 |
| OAK 2199852 | Britax Child Safety, Inc. | 12 Vehicles | Pending | 2022 |
| Oaksea 2194438 · TMA1235104 | Shenzhen Feituo Tianxia Trading Co. Ltd. | 21 Housewares | Registered | 2024 |
| OAKIO 2045859 · TMA1144799 · design | Huizhou Oakio Plastic Wood Building Materials Co.Ltd | 19 Building | Registered | 2022 |
| OAKKY 2033122 · TMA1161122 · design | PUTIAN YAJIU TRADING CO. LTD. | 14 Jewellery | Registered | 2023 |
| OAIKA 1955656 · TMA1255634 | BANFF WATER LTD. | 5 Pharmaceuticals29 Meat30 Coffee+3 | Registered | 2024 |
| OAIKA 1873983 · TMA1060392 | BANFF WATER LTD. | 32 Beer35 Advertising | Registered | 2019 |
| ohyeahus 2264292 · TMA1283374 | an individual | 5 Pharmaceuticals | Registered | 2025 |
| OOSSXX 2258072 · TMA1277735 · design | Shenzhenshi Xiankailike Technology Co. Ltd | 9 Electronics | Registered | 2024 |
| OKK 2256870 · TMA1276298 · design | OKK INTERNATIONAL (HONG KONG) CO. LIMITED | 34 Tobacco | Registered | 2024 |
| OKG 2254704 · TMA1273110 | Shanghai NVSMART Technology Co. Ltd. | 6 Metal9 Electronics17 Rubber | Registered | 2024 |
| OK 2253930 · TMA1273003 · design | Astral IP Enterprise Ltd. | 9 Electronics | Registered | 2024 |
| OSQ 2253155 · TMA1270254 | Owner not listed | 11 Lighting | Registered | 2024 |
| OHJA 2248120 · TMA1253153 · design | an individual | 34 Tobacco | Registered | 2024 |
| OHJA 2248116 · TMA1253152 | an individual | 34 Tobacco | Registered | 2024 |
| OQQ 2246999 · TMA1267154 | Hangzhou Tabo E-commerce Co. Ltd | 25 Clothing | Registered | 2024 |