| Company name | Reg. code |
|---|---|
| FDREI OÜ | 17472111 |
| DREI TECHNIK OÜ (former name Rustair OÜ) | 14767231 |
| DREI KAPITAL OÜ | 11976336 |
| DREI FLÜGE OÜ (former name Profix Solutions OÜ) | 14103436 |
| DREI DIGITAL OÜ (former name XL Building OÜ) | 14354724 |
| FREI VISUALS OÜ (former name Frei Investment OÜ) | 16281998 |
| PANEELPUIT OÜ (former name Drei Haus OÜ) | 12868382 |