| Company Logo | Company name | Country | Sector |
|---|---|---|---|
 | Oshika Corporation |  Japan | Manufacturing, Chemicals |
| | Oshika Corporation | Japan | Manufacturing, Chemicals |
 | Okitsumo Incorporated | Japan | Manufacturing |
 | Ogura Jewel Industry Co.,Ltd. | Japan | Manufacturing |
 | Oiles Corporation | Japan | Manufacturing |
 | OPHTECS Corporation | Japan | Medical |
 | OHARA INC. | Japan | Manufacturing |
 | OMORI MACHINERY CO., LTD. | Japan | Manufacturing |
 | Ohmi Press Works & Forging Co., Ltd. | Japan | Manufacturing |
 | Okabe | Japan | Manufacturing |
 | OHISHI SANGYO CO., LTD. | Japan | Others |
 | OAT Agrio Co., Ltd. | Japan | Manufacturing, Manufacturing |
