| OCTECH 2021405 · TMA1263793 | Shenzhen Able Electronics Co. Ltd | 21 Housewares35 Advertising | Registered | 2024 |
| OSTACO 2040903 · TMA1282033 | Owner not shown | 6 Metal19 Building37 Construction+2 | Registered | 2025 |
| OYSTEC 2000665 · TMA1160924 | Oystec GmbH & Co. KG | 9 Electronics35 Advertising36 Finance+2 | Registered | 2023 |
| OSTAC 0642471 · TMA385131 | Esteve Pharmaceuticals GmbH | 5 Pharmaceuticals | Registered | 1991 |
| OSTEOCIT 1195475 · TMA623249 | SEAFORD PHARMACEUTICALS INC. | 5 Pharmaceuticals | Registered | 2004 |
| OSTEOCHRON 1551176 · TMA890917 | MARKET WATCH FRANCHISE & CONSULTING, INC. | 5 Pharmaceuticals | Registered | 2014 |
| OSTEOJECT 1833538 · TMA1033851 | Grey Wolf Animal Health Inc. | 5 Pharmaceuticals | Registered | 2019 |
| OsteoCool 1820852 · TMA1069789 | Medtronic Holding Company Sàrl | 10 Medical | Registered | 2020 |
| OSTEOCARE 0898436 · TMA522730 | VITABIOTICS LTD | 5 Pharmaceuticals | Registered | 2000 |
| OSTEOWASH 2247109 | OsteoRemedies, LLC | 5 Pharmaceuticals | Pending | 2023 |
| OihcDosff 2250734 · TMA1276080 | Shenzhen Color Bag E-Commerce Co. Ltd | 11 Lighting | Registered | 2024 |
| OQTIQ 2249305 · TMA1268656 | Owner not listed | 9 Electronics | Registered | 2024 |
| OsteoSync 2213391 · TMA1232935 | SMED-TA/TD, LLC | 10 Medical | Registered | 2024 |
| OXDOG 2183696 · TMA1254921 | an individual | 28 Toys | Registered | 2024 |
| OctsumYing 2175194 · TMA1226166 | Guangzhou Yingbohe Trading Co. Ltd. | 21 Housewares | Registered | 2024 |
| Octocurl 2132424 · TMA1194343 | an individual | 26 Sewing | Registered | 2023 |
| OSTEOCONNECT 2113416 · TMA1208435 | Smith & Nephew, Inc. | 10 Medical | Registered | 2023 |
| Okydoky 2106201 · TMA1176625 | Zhenhui Technology (Shenzhen) Co. Ltd. | 27 Carpets | Registered | 2023 |
| OCTOGOLD 2072249 · TMA1282229 | DURADRIVE SYSTEMS INTERNATIONAL INC. | 1 Chemicals6 Metal | Registered | 2025 |
| OctaCoil 2068831 · TMA1280252 | SE Therapies Ltd. | 10 Medical | Registered | 2025 |
| OCTAS 2054480 · TMA1244891 · design | Bright International Group Holdings Ltd. | 11 Lighting35 Advertising | Registered | 2024 |
| OXDIGI 2034462 · TMA1138662 · design | Shanghai FeiTuYou Technology Co. Ltd | 9 Electronics | Registered | 2022 |
| OCTAGON 2030316 · TMA1165356 | Interprovincial Cooperative Limited | 5 Pharmaceuticals | Registered | 2023 |
| Ostazt 1989828 · TMA1130357 | Shenzhen Yinuo Technology Co. Ltd. | 9 Electronics | Registered | 2022 |
| OXDOG 1989555 · TMA1111333 | an individual | 9 Electronics25 Clothing28 Toys | Registered | 2021 |