| OCHO 1600506 · TMA888803 | Major League Global Enterprise Limited | 9 Electronics | Registered | 2014 |
| OCHI 1378939 · TMA743052 | OCHI TRADING CO. LTD. | 6 Metal9 Electronics14 Jewellery+10 | Registered | 2009 |
| OCIO 1188666 · TMA671502 | an individual | 33 Wine | Registered | 2006 |
| OCCO 2356173 | an individual | 3 Cosmetics10 Medical | Pending | 2024 |
| OCIO 2236207 | 3iQ Corp. | 9 Electronics35 Advertising36 Finance+1 | Pending | 2023 |
| OCCO 2188897 | 1770415 Alberta Ltd. | 5 Pharmaceuticals29 Meat30 Coffee+1 | Pending | 2022 |
| OCCO 2152217 | 1770415 Alberta Ltd. | 31 Fresh35 Advertising42 Science+2 | Pending | 2021 |
| OCIO 1981859 | OCIO Naturals Inc. | 3 Cosmetics32 Beer34 Tobacco | Pending | 2019 |
| OCIO 1981858 · design | OCIO Naturals Inc. | 3 Cosmetics32 Beer34 Tobacco | Pending | 2019 |
| OXCIA 2176456 · TMA1284409 | an individual | 5 Pharmaceuticals10 Medical42 Science | Registered | 2025 |
| OSCOO 2056375 · TMA1193289 · design | Shenzhen Oscoo Tech. Co. Ltd | 9 Electronics | Registered | 2023 |
| OAKIO 2045859 · TMA1144799 · design | Huizhou Oakio Plastic Wood Building Materials Co.Ltd | 19 Building | Registered | 2022 |
| OHCO 2032531 · TMA1165376 | FFL Brands LLC | 10 Medical | Registered | 2023 |
| OUSHI 1981855 · TMA1271936 | Guangzhou Qisi Technology Co. Ltd. | 11 Lighting | Registered | 2024 |
| OCI 1964266 · TMA1119950 | Siemens Healthcare GmbH | 9 Electronics16 Paper35 Advertising+1 | Registered | 2022 |
| OSSIO 1933085 · TMA1137894 | OSSIO LTD | 10 Medical | Registered | 2022 |
| OSHO 1863805 · TMA1095081 | Osho International Foundation | 9 Electronics16 Paper35 Advertising+4 | Registered | 2021 |
| OHSO 1837991 · TMA1012203 | an individual | 3 Cosmetics21 Housewares26 Sewing+2 | Registered | 2019 |
| OCCA 1607712 · TMA891089 | RZIM Zacharias Trust | 41 Education45 Legal | Registered | 2014 |
| OCC 1583070 · TMA877144 · design | Oxford College of Canada Inc | 9 Electronics16 Paper41 Education | Registered | 2014 |
| OCI 1561935 · TMA892576 | an individual | 1 Chemicals | Registered | 2014 |
| OCÓO 1554934 · TMA985031 | pure product GmbH | 5 Pharmaceuticals32 Beer33 Wine | Registered | 2017 |
| OGIO 1490099 · TMA800530 | Winery Exchange, Inc. | 33 Wine | Registered | 2011 |
| OJIO 1460314 · TMA843515 · design | Ultimate Superfoods, Inc. | 29 Meat30 Coffee31 Fresh+1 | Registered | 2013 |
| OJIO 1460313 · TMA843495 | Ultimate Superfoods, Inc. | 29 Meat30 Coffee31 Fresh+1 | Registered | 2013 |