| Company name | Reg. code |
|---|---|
| OY OÜ | 16921423 |
| OY GAMES OÜ kustutatud | 12994135 |
| HASS NORD OY OÜ kustutatud | 16888476 |
| 20200202 AB OY LTD OÜ | 14904840 |
| PAPINIIDU MAJAD OY OÜ | 14161882 |
| AK KINNISVARAHOOLDUS OY OÜ | 14722984 |
| ROYAL DESIGN EHITUS OY OÜ | 16510128 |
| H3 PROJEKT OÜ (former name Hassi Oy OÜ) | 16527301 |
| ÖYAN OÜ | 16941727 |
| OYKO OÜ | 14267250 |
| OYLA OÜ | 17229623 |
| OYNER OÜ | 16739575 |
| OYRAM OÜ | 12072803 |
| Ouman Oy | 2447613-4 |
| OYERAF OÜ | 16735790 |
| OYSTER OÜ kustutatud | 11604652 |
| OYUNEKS OÜ | 16567476 |
| OYE SERGI OÜ | 17064814 |
| OYSTERBOYS OÜ | 16064427 |
| OYE NETWORK OÜ | 12258206 |
| OURA HEALTH OY | 65551233 |
| OYE HOLDINGS OÜ | 11488000 |
| OYTEN MINING OÜ kustutatud | 14731351 |
| OYE TEENUSED OÜ | 11229237 |
| ÖYE PACKAGING OÜ | 16760411 |
| OYASIN CAPITAL OÜ | 17329135 |
| OYASIN HOLDING OÜ | 16443969 |
| OYOS ENTERPRISE OÜ kustutatud (former name Hempy Enterprise OÜ) | 14979559 |
| ÖYVIND HJULMAND OÜ | 10908019 |
| OUTOTEC (FINLAND) OY | 60066738 |
| OYKO THUN COMPANY OÜ kustutatud | 11443870 |
| OYSTER TELECOMMUNICATION OÜ kustutatud | 16993374 |
| TATIANA OYNUS PHOTOGRAPHER OÜ | 14424577 |