| Hire Falun AB CVR 5565598025 | BoardDeputy Board Member | Since 2025 | — | Dissolved |
| Svenska Undervattensentreprenader AB CVR 5565678785 | BoardBoard of Directors | Since 2026 | — | Active |
| Uw-Tech AB CVR 5569195539 | BoardBoard of Directors | Since 2022 | — | Active |
| Land & Dykservice Nord AB CVR 5569783201 | BoardBoard of Directors | Since 2026 | — | Active |
| SVENSKA UNDERVATTENSENTREPRENADER MASKIN AB CVR 5592278203 | BoardBoard of Directors | Since 2026 | — | Active |
| Uw-Tech Group AB CVR 5593089138 | BoardBoard of Directors | Since 2025 | — | Active |
| 4 Sustainability AB CVR 5593476004 | BoardBoard of Directors | Since 2022 | — | Active |
| Offshore-Tech Sweden AB CVR 5593890568 | BoardBoard of Directors | Since 2026 | — | Active |
| 4 Sustainability Electronic I AB CVR 5594531682 | BoardBoard of Directors | Since 2023 | — | Active |
| Swe-Sub Marin AB CVR 5594588468 | BoardBoard of Directors | Since 2026 | — | Active |
| 4 Sustainability Partner II AB CVR 5594929787 | BoardBoard of Directors | Since 2024 | — | Active |
| 4 Sustainability Holding III AB CVR 5595099606 | BoardBoard of Directors | Since 2025 | — | Active |
| UW-Tech Marine AB CVR 5595099622 | BoardBoard of Directors | Since 2025 | — | Active |
| Carlberg Properties AB CVR 5595102061 | BoardDeputy Board Member | Since 2025 | — | Active |
| Carlberg Properties i Dalarna AB CVR 5595102079 | BoardDeputy Board Member | Since 2025 | — | Active |
| Sub Marin Holding AB CVR 5595324434 | BoardBoard of Directors | Since 2026 | — | Active |
| Swe-Sub Equipment AB CVR 5595324517 | BoardBoard of Directors | Since 2026 | — | Active |
| Full Send AB CVR 5595554303 | BoardDeputy Board Member | Since 2025 | — | Active |
| Uw-Tech Engineering AB CVR 5595579029 | BoardBoard of Directors | Since 2026 | — | Active |
| Elektrikerna i Falun AB CVR 5595745646 | BoardDeputy Board Member | Since 2026 | — | Active |