| Company name | Reg. code |
|---|---|
| OPTIMALINE OÜ (former name UÜ OptimaLine) | 12983545 |
| OPTIMALONE OÜ (former name Optimalone UÜ) | 14056872 |
| OPTIMAFIN OÜ | 17111324 |
| OPTIMAALNE TEADLIKKUS OÜ | 16506776 |
| OPTILINE GRUPP OÜ | 10528251 |
| OPTILINE ILLUSIOON OÜ | 16250974 |
| MIRRU GRUPP OÜ (former name Merlemar OÜ) | 14806563 |