| Company name | Reg. code |
|---|---|
| PROTOS OÜ | 12210599 |
| PROTOS VARA OÜ | 11460762 |
| PROTOS SERVICE OÜ (former name Kilbitehas OÜ) | 12503189 |
| PROPOS OÜ | 16412466 |
| PROTSO OÜ | 14404876 |
| PROTONS OÜ | 14730423 |
| PROTOC OÜ | 12393743 |
| PROTO OÜ (former name Noblessner Park OÜ) | 14158153 |
| PROTON INVEST OÜ kustutatud | 11968897 |
| PROTON ONE OÜ | 10722220 |
| PROPOS-B OÜ | 10115566 |
| PRONOS RIPPLAED OÜ | 14131510 |
| PRONOS GRUPP OÜ | 12035357 |
| VIDEO PROTON OÜ | 14593452 |
| PROOS INVEST OÜ | 11225819 |
| PROTO-TESTING OÜ | 17403185 |
| 3D-PROTO OÜ | 10519855 |
| A-PROTO OÜ | 10463333 |
| KMK PROTO OÜ | 14135927 |
| ENGINEERING PROTO OÜ | 14510578 |
| PROTON VENTURES ESTONIA OÜ kustutatud | 11392546 |
| PROOS-S EHITUS OÜ kustutatud | 12739905 |
| PROTOSYS OÜ | 16662890 |
| PROTOSHOP OÜ | 16914630 |
| PROTOSTAR OÜ kustutatud | 11477604 |
| PROTOSKOOP OÜ | 14051171 |
| PROTOSONIC OÜ | 16344167 |
| PRORES OÜ (former name ProRes Viimistlus OÜ) | 16094026 |
| PROTOSÜSTEEMID OÜ kustutatud | 11628167 |
| PROTOSALES GROUP OÜ | 17092868 |
| KROTOS OÜ kustutatud | 10617322 |
| PORTOS OÜ | 12034487 |
| PROBUS HOUSE OÜ (former name Heeven Trading OÜ) | 14273368 |
| NURLEINLO LEIDOREFOKE OÜ (former name PRORIOS OÜ) | 16160450 |
| CARMENM PHOTOS OÜ | 16914541 |
| PROANS OÜ kustutatud | 14634518 |
| PRODES OÜ | 10905618 |
| PROOTON OÜ kustutatud | 12974405 |
| PROOST OÜ kustutatud | 12360548 |
| PROCON OÜ | 12799289 |
| PROLOX OÜ | 14848120 |
| PROMOP OÜ | 16773307 |
| PROMOSA OÜ kustutatud | 10139397 |
| PROKUS OÜ kustutatud | 11648951 |
| PROBUS OÜ | 10655707 |
| PROINS OÜ | 12704462 |
| PRONKS OÜ | 10270752 |
| PROPAS OÜ | 16664216 |
| PROFOUS OÜ | 10465757 |
| PROKOM OÜ kustutatud | 10933709 |