| ONTO ENTERPRISES LIMITED | Private company limited by shares | Dissolved |
| ONTO LOGISTIC LIMITED | Private company limited by shares | Live |
| ONTO SUCCESS LIMITED | Private company limited by shares | Dissolved |
| ONTOCAR SERVICE COMPANY LIMITED | Private company limited by shares | Live |
| Ontocaress Company Limited | Private company limited by shares | Live |
| ONTOES LIMITED | Private company limited by shares | Dissolved |
| Ontolo Finance Limited | Private company limited by shares | Live |
| Ontology Research Association Limited | Private company limited by shares | Live |
| OntologyNet Limited | | Live |
| ONTON LIMITED | Private company limited by shares | Dissolved |
| ONTON LIMITED | Private company limited by shares | Live |
| ONTON INVESTMENT LIMITED | Private company limited by shares | Dissolved |
| ONTON TEXTILES LIMITED | Private company limited by shares | Dissolved |
| ONTON TRANSPORTATION LIMITED | Private company limited by shares | Dissolved |
| ONTONE LIMITED | Private company limited by shares | Live |
| ONTONE COMPUTER COMPANY LIMITED | Private company limited by shares | Dissolved |
| Ontone Creation Limited | Private company limited by shares | Live |
| ONTONE FINANCE COMPANY LIMITED | Private company limited by shares | Live |
| ONTONOMIA LIMITED | Private company limited by shares | Live |
| Ontoo Technology Limited | | Live |
| ONTOP COMPANY LIMITED | Private company limited by shares | Dissolved |
| ONTOP LIMITED | Private company limited by shares | Dissolved |
| ONTOP LIMITED | Private company limited by shares | Dissolved |
| ONTOP LIMITED | Private company limited by shares | Dissolved |
| ONTOP LIMITED | Private company limited by shares | Live |
| ONTOP 43 LIMITED | | Live |
| ONTOP ENTERPRISES LIMITED | Private company limited by shares | Dissolved |
| ONTOP ENTERPRISES LIMITED | Private company limited by shares | Dissolved |
| Ontop Finance Limited | Private company limited by shares | Live |
| ONTOP FURNITURE LIMITED | Private company limited by shares | Live |
| ONTOP INC. LIMITED | Private company limited by shares | Dissolved |
| ONTOP PROPERTIES LIMITED | Private company limited by shares | Live |
| Ontopoint Company Limited | Private company limited by shares | Live |
| ONTOR LIMITED | Private company limited by shares | Live |
| Ontour Company Limited | Private company limited by shares | Live |
| Ontour Air Ticketing Co. , Limited | | Live |
| ONTOWN COMPANY LIMITED | Private company limited by shares | Dissolved |
| ONTOZ COMPANY LIMITED | Private company limited by shares | Live |