| OVALIS 1850146 · TMA1076815 · design | Osaka University and Taisho Biomed Instruments Co. Ltd. | 10 Medical | Registered | 2020 |
| OVALIS 1778512 · TMA1041478 | Osaka University and Taisho Biomed Instruments Co. Ltd. | 10 Medical | Registered | 2019 |
| OVALUX 1948920 · TMA1136992 | Gammalux Lighting Systems Inc. | 11 Lighting | Registered | 2022 |
| OPALS 0746529 · TMA452123 | Morgan Stanley (a Delaware Corporation) | 36 Finance | Registered | 1995 |
| OVILUS 2094953 | Chapp Inc | 9 Electronics | Pending | 2021 |
| OBELYSK 1280125 · TMA731113 | Obelysk Inc. | 35 Advertising36 Finance | Registered | 2008 |
| OHFULLS 2231155 · TMA1256534 | Shenzhen Oufos Trading Co. LTD | 11 Lighting | Registered | 2024 |
| OPALCETIC 2220690 · TMA1261341 | Owner not shown | 2 Paints | Registered | 2024 |
| OVLUX 2211801 · TMA1243019 | an individual | 8 Hand9 Electronics11 Lighting | Registered | 2024 |
| OPLIXEL 2138210 · TMA1206195 | an individual | 1 Chemicals5 Pharmaceuticals | Registered | 2023 |
| OPLXS 2105395 · TMA1189587 | an individual | 28 Toys | Registered | 2023 |
| OBLIX 2082213 · TMA1208303 · design | Azumi Limited | 43 Restaurants | Registered | 2023 |
| OBELISK 2073442 · TMA1190457 | SHENZHEN GEEKVAPE TECHNOLOGY CO. LTD. | 34 Tobacco | Registered | 2023 |
| OPULUS 2042673 · TMA1190366 | REA Innovations, Inc. | 3 Cosmetics21 Housewares | Registered | 2023 |
| OPULUX 1904861 · TMA1089433 | The Dow Chemical Company | 1 Chemicals | Registered | 2020 |
| OPLAGTRI 1873767 · TMA1057770 | BRISTOL-MYERS SQUIBB COMPANY (A DELAWARE CORPORATION) | 5 Pharmaceuticals | Registered | 2019 |
| OPALHOUSE 1853957 · TMA1079780 · design | Target Brands, Inc. | 16 Paper21 Housewares | Registered | 2020 |
| OPALHOUSE 1853956 · TMA1076532 · design | Target Brands, Inc. | 6 Metal14 Jewellery20 Furniture+1 | Registered | 2020 |
| OPALHOUSE 1853955 · TMA1076538 · design | Target Brands, Inc. | 19 Building | Registered | 2020 |
| OPALHOUSE 1853954 · TMA1081208 · design | Target Brands, Inc. | 18 Leather | Registered | 2020 |
| OPALHOUSE 1853953 · TMA1076540 · design | Target Brands, Inc. | 6 Metal | Registered | 2020 |
| OPALHOUSE 1853952 · TMA1079772 · design | Target Brands, Inc. | 16 Paper20 Furniture | Registered | 2020 |
| OPALHOUSE 1853951 · TMA1076533 · design | Target Brands, Inc. | 14 Jewellery | Registered | 2020 |
| OPALHOUSE 1853950 · TMA1081205 · design | Target Brands, Inc. | 11 Lighting | Registered | 2020 |
| OPALHOUSE 1853949 · TMA1079268 · design | Target Brands, Inc. | 8 Hand21 Housewares | Registered | 2020 |