| OYOCO 2058526 · TMA1154169 | an individual | 11 Lighting | Registered | 2022 |
| Oigco 2095894 · TMA1187346 | Jinhua Xichun Paper Products Co. Ltd. | 21 Housewares | Registered | 2023 |
| OHCO 2032531 · TMA1165376 | FFL Brands LLC | 10 Medical | Registered | 2023 |
| OASO 2025593 · TMA1158920 | an individual | 28 Toys | Registered | 2023 |
| OEAGO 1891106 · TMA1067374 | an individual | 9 Electronics | Registered | 2019 |
| OSCO!! 1434919 · TMA771487 | Corporation des Hotels Intercontinental (Montreal) inc. | 43 Restaurants | Registered | 2010 |
| OKAO 1351292 · TMA757262 · design | OMRON CORPORATION | 9 Electronics28 Toys40 Treatment+3 | Registered | 2010 |
| OYSHO 1297148 · TMA884826 | INDUSTRIA DE DISENO TEXTIL, S.A. (INDITEX, S.A.) a Spanish company | 1 Chemicals2 Paints5 Pharmaceuticals+10 | Registered | 2014 |
| OKAO 1294142 · TMA737776 | OMRON CORPORATION | 9 Electronics28 Toys40 Treatment+3 | Registered | 2009 |
| OYSHO 1089261 · TMA853829 | INDUSTRIA DE DISENO TEXTIL, S.A. (INDITEX, S.A.) a Spanish company | 3 Cosmetics5 Pharmaceuticals6 Metal+17 | Registered | 2013 |
| OSCO 0236161 · TMA105467 | OCEAN STEEL & CONSTRUCTION LTD. | 6 Metal36 Finance | Registered | 1957 |
| OCCO 2356173 | an individual | 3 Cosmetics10 Medical | Pending | 2024 |
| OYSHO 2269289 | Owner not listed | 9 Electronics35 Advertising41 Education+1 | Pending | 2023 |
| OSCO 2209957 | an individual | 32 Beer | Pending | 2022 |
| OAC 2199302 | On Clouds GmbH | 25 Clothing36 Finance41 Education | Pending | 2022 |
| OCCO 2188897 | 1770415 Alberta Ltd. | 5 Pharmaceuticals29 Meat30 Coffee+1 | Pending | 2022 |
| OCCO 2152217 | 1770415 Alberta Ltd. | 31 Fresh35 Advertising42 Science+2 | Pending | 2021 |
| OIAC 0973242 | Owner not shown | 1 Chemicals2 Paints3 Cosmetics+42 | Pending | 2014 |
| OACI 0971751 | Owner not shown | 1 Chemicals2 Paints3 Cosmetics+42 | Pending | 1997 |
| OAC 0919747 | UNIVERSITY OF GUELPH | 1 Chemicals2 Paints3 Cosmetics+42 | Pending | 2009 |
| 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 |