| Company name | Reg. code |
|---|---|
| QTBC OÜ | 16877797 |
| QTB LINGUA OÜ kustutatud | 12248432 |
| TBC OÜ kustutatud | 12430527 |
| TBC INTERNATIONAL OÜ (former name The Best Company OÜ) | 16811321 |
| TBC EUROPE OÜ | 14231341 |
| TBC HUS OÜ kustutatud | 12578520 |
| TBC-CTT OÜ kustutatud (former name Eastern Invest OÜ) | 11784370 |
| TBC EHITUS OÜ | 14977036 |
| QBC GROUP OÜ | 11440357 |