| OCAN 2002001 · TMA1131558 | an individual | 5 Pharmaceuticals | Registered | 2022 |
| OCUN 1933847 · TMA1239216 · design | Owner not shown | 3 Cosmetics6 Metal9 Electronics+3 | Registered | 2024 |
| OCEAN 2056861 · TMA1283950 | Azul 3D, Inc. | 7 Machines40 Treatment | Registered | 2025 |
| Oecon 2005983 · TMA1140355 | Shenzhen Lejianshang Technology Co. Ltd. | 25 Clothing | Registered | 2022 |
| OCEAN 1999509 · TMA1117475 · combined | Hawaii Sea Spirits, LLC | 33 Wine | Registered | 2022 |
| OCEAN 1899885 · TMA1088412 | Hawaii Sea Spirits, LLC | 33 Wine | Registered | 2020 |
| OCANA 1885883 · TMA1094989 | Grand Health Inc. | 5 Pharmaceuticals | Registered | 2021 |
| OCEAN 1847063 · TMA1070161 · design | Public Joint Stock Company Gazprom Neft | 4 Oils | Registered | 2020 |
| OCION 1765266 · TMA973413 | Ocion Water Science Inc. | 1 Chemicals | Registered | 2017 |
| OXYN8 1569841 · TMA859833 · design | BIOMAXX WASTEWATER SOLUTIONS INC. | 1 Chemicals | Registered | 2013 |
| OXYNE 1463550 · TMA833347 | Ensilver Corp. | 35 Advertising37 Construction40 Treatment+1 | Registered | 2012 |
| OCEAN 1454236 · TMA825572 · design | LEHIGH HANSON MATERIALS LIMITED | 7 Machines11 Lighting17 Rubber+1 | Registered | 2012 |
| OCEAN 1429419 · TMA825582 | LEHIGH HANSON MATERIALS LIMITED | 7 Machines11 Lighting17 Rubber+1 | Registered | 2012 |
| OCEAN 1381484 · TMA740170 | Schlumberger Canada Limited | 9 Electronics42 Science | Registered | 2009 |
| OCEAN 1346143 · TMA730340 | Oceanside Equipment Limited | 6 Metal7 Machines8 Hand | Registered | 2008 |
| OCEAN 1301484 · TMA698878 | ATRIUM MEDICAL CORPORATION, a legal entity | 10 Medical | Registered | 2007 |
| OCEAN 1115073 · TMA585161 | Flame Control Coatings, LLC | 2 Paints | Registered | 2003 |
| OCENA 1098258 · TMA611080 · design | Teranet Inc. | 16 Paper25 Clothing42 Science | Registered | 2004 |
| OCENA 1079173 · TMA602028 | Teranet Inc. | 8 Hand14 Jewellery16 Paper+6 | Registered | 2004 |
| OCEAN 0991252 · NFLD1252 | THE STANDARD MANUFACTURING COMPANY LIMITED | 1 Chemicals2 Paints10 Medical+2 | Registered | 1924 |
| OCEAN 0673598 · TMA412266 | an individual | 9 Electronics | Registered | 1993 |
| OCEAN 2101881 · design | Owner not shown | 16 Paper20 Furniture21 Housewares+1 | Pending | 2021 |
| OCSAN 0971456 | Owner not shown | 1 Chemicals2 Paints3 Cosmetics+42 | Pending | 2002 |
| OSNO 2265566 · TMA1284961 | 3097-1238 Quebec Inc. | 25 Clothing35 Advertising | Registered | 2025 |
| OSHIN 2256373 · TMA1283028 | Suzhou rizi office & stationery co.ltd | 16 Paper | Registered | 2025 |