| | | | | |
| Subsidiary Name | State or Country of Incorporation or Formation |
| CyrusOne GP | Maryland |
| CyrusOne LP | Maryland |
| CyrusOne Finance Corp. | Maryland |
| CyrusOne LLC | Delaware |
| CyrusOne TRS Inc. | Delaware |
| CyrusOne Foreign Holdings LLC | Delaware |
| CyrusOne Government Services LLC | Delaware |
| Cervalis Holdings LLC | Delaware |
| Cervalis LLC | Delaware |
| Cyrus One UK Limited | United Kingdom |
| CyrusOne NC LLC | Delaware |
| CyrusOne NJ LLC | Delaware |
| C1-Allen LLC | Delaware |
| Cheetah Asia Holdings LLC | Delaware |
| Warhol TRS LLC | Delaware |
| Warhol Partnership LLC | Delaware |
| Warhol REIT LLC | Delaware |
| CyrusOne Dutch Holdings B.V. | Netherlands |
| C1-Santa Clara LLC | Delaware |
| C1-ATL LLC | Delaware |
| Interlude Properties LLC | Delaware |
| GK Properties IV LLC | Delaware |
| CyrusOne New Services TRS | Delaware |
| C1- Mesa LLC | Delaware |
| Zenium Management Limited | United Kingdom |
| CyrusOne Irish Datcentres Dublin II Limited | Ireland |
| CyrusOne Germany GmbH | Germany |
| CyrusOne UK3 Limited | United Kingdom |
| CyrusOne Dutch TRS B.V. | Netherlands |
| C1-Sterling VIII LLC | Delaware |
| Zenium Topco Limited | Cayman Islands |
| CyrusOne Irish Datcentres Holdings Limited | Ireland |
| CyrusOne Paris SAS | France |
| CyrusOne UK4 Limited | United Kingdom |
| C1 BTE Holdings LLC | Delaware |
| CyrusOne UK TRS Limited | United Kingdom |
| CyrusOne German TRS GmbH | Germany |
| C1-Sterling IX LLC | Delaware |
| Zenium Holdings Limited | Ireland |
| CyrusOne AMS3 B.V. | Netherlands |
| CyrusOne France SAS | France |
| C1 BTE Holdings Columbia LLC | Delaware |
| CyrusOne France SAS | France |
| CyrusOne UK5 Limited | United Kingdom |
| Zenium Technology Partners Limited | United Kingdom |
| Zenium UK Limited | United Kingdom |
| Zenium Germany GmbH | Germany |
| Echo 4 GmbH | Germany |
| C1 - Manassas LLC | Delaware |
| C1 San Antonio V | Delaware |
| CyrusOne Holdings LLC | Delaware |
| C1 - Quincy LLC | Delaware |
| C1 - Council Bluffs LLC | Delaware |
| C1 BTE Holdings Chile LLC | Delaware |
| C1 BTE Holdings Mexico LLC | Delaware |
| CyrusOne Frankfurt 4 Holdings B.V. | Netherlands |
| CyrusOne Management Services LLC | Delaware |
| CyrusOne Frankfurt 5 Holdings B.V. | Netherlands |
| CyrusOne UK6 Limited | United Kingdom |
| CyrusOne Europe Finance DAC | Ireland |
| CyrusOne Madrid 1, S.L.U. – Spain | Spain |
| CyrusOne Frankfurt 6 Holdings B.V. | Netherlands |
| CyrusOne Frankfurt 7 Holdings B.V. | Netherlands |