| ONTAR LIMITED | Private company limited by shares | Live |
| ONTARGET LIMITED | Private company limited by shares | Live |
| On-Target Advertising Limited | | Live |
| ONTARGET ASIA LIMITED | Private company limited by shares | Dissolved |
| ONTARIO LIMITED | Private company limited by shares | Dissolved |
| ONTARIO COMPANY LIMITED | | Live |
| NO. 505746 ONTARIO (HK) LIMITED | Private company limited by shares | Dissolved |
| Ontario eSchool Asia Limited | Private company limited by shares | Live |
| ONTARIO CENTURY ENTERPRISE LIMITED | Private company limited by shares | Dissolved |
| ONTARIO ENTERPRISES LIMITED | Private company limited by shares | Dissolved |
| ONTARIO FINANCE LIMITED | Private company limited by shares | Live |
| ONTARIO FINANCE AND INVESTMENT COMPANY, LIMITED | Private company limited by shares | Dissolved |
| ONTARIO INVESTMENT LIMITED | Private company limited by shares | Dissolved |
| LAKE ONTARIO LIMITED | Private company limited by shares | Live |
| PORT ONTARIO LIMITED | Private company limited by shares | Dissolved |
| Talent Ontario Limited | | Live |
| ONTARIO TECHNOLOGY LIMITED | Private company limited by shares | Dissolved |
| ONTARIO-CENTURY COMPANY LIMITED | Private company limited by shares | Dissolved |
| ONTARKEE COMPANY LIMITED | Private company limited by shares | Dissolved |
| ONTARY COMPANY LIMITED | Private company limited by shares | Dissolved |