| Company name | Reg. code |
|---|---|
| CITYKEY OÜ | 14563401 |
| CITYSKY OÜ (former name Citysky UÜ) | 16019533 |
| CITYWEB OÜ | 12339695 |
| CITYSEC OÜ | 10030232 |
| CITYJET OÜ kustutatud | 14306794 |
| CITYREM OÜ | 12640294 |
| CITYNET OÜ | 12814707 |
| CITYBEE EESTI OÜ | 14646800 |
| CITYSEC KOOLITUS OÜ (former name Citysec Foods OÜ) | 12239025 |
| CITYSEC INDUSTRY OÜ (former name OÜ CIYTSEC INDUSTRY) | 17271884 |
| CITYSEC CONNECTION OÜ kustutatud | 12242837 |
| CITYSEC TURVATEENISTUS OÜ (former name Citysec Security OÜ) | 12390518 |
| CITYSEC ENERGY SOLUTIONS OÜ kustutatud | 10777043 |
| ITKEY SYSTEMS OÜ (former name OÜ ITK System) | 12718085 |