| QUANTUMTEK CO., LIMITED | Private company limited by shares | Live |
| Quantumtime Limited | Private company limited by shares | Live |
| QuantumTrust Solutions Limited | | Live |
| QuantumTX Hong Kong Limited | | Live |
| Quantumverse Limited | | Live |
| QuantumWhale Limited | | Live |
| QUANTURN LIMITED | Private company limited by shares | Live |
| QUANTUS LIMITED | Private company limited by shares | Live |
| Quantus Inc Limited | Private company limited by shares | Live |
| Quantweb Limited | Private company limited by shares | Live |
| QUANTWIN LIMITED | Private company limited by shares | Live |
| QUANTZ LIMITED | Private company limited by shares | Dissolved |