| QUANTUMCODE LIMITED | | Live |
| QuantumCyte Technology Limited | Private company limited by shares | Live |
| Quantumdots Limited | | Live |
| QuantumFabless Limited | Private company limited by shares | Live |
| QUANTUMFACTORY CO. LIMITED | Private company limited by shares | Live |
| QuantumFlow Limited | | Live |
| QuantumForge Limited | | Live |
| QUANTUMIZE LIMITED | | Live |
| QuantumKDB Limited | Private company limited by shares | Live |
| Quantumlink Limited | Private company limited by shares | Dissolved |
| QuantumMeta Limited | | Live |
| QUANTUMMIND SOLUTIONS HONG KONG LIMITED | | Live |
| QuantumNova Limited | | Live |
| QuantumPharm Limited | Private company limited by shares | Live |
| QUANTUMPLAN LIMITED | Private company limited by shares | Dissolved |
| QuantumPulse Enterprises Limited | | Live |
| QuantumS Limited -The- | Private company limited by shares | Live |
| QUANTUMSIL LIMITED | Private company limited by shares | Live |
| Quantumsis Co., Limited | | Live |
| Quantumspace Limited | | Live |
| SHENZHEN QUANTUMSTAR TECHNOLOGY CO., LIMITED | Private company limited by shares | Dissolved |
| QuantumTech Limited | | Live |
| Carl Quantum-Tech Co., Limited | | Live |
| 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 |