- CITIC Telecom Estonia OÜ
- Telia Eesti AS
- Elisa Eesti AS
- Tele2 Eesti AS
- Relacom Poland
- Leonhard Weiss Energy AS
- KH-Energia-Konsult AS
- Empower AS
- AS Elektritsentrum
- Telegrupp AS
- Optimus Systems AS
- Nordecon AS
- AS YIT Eesti
- Merko Ehitus Eesti AS
- AS Merko Infra
- Tallinna Teede AS
- AS Teede REV-2
- TREF Nord AS
