| | | | | | | | | | | | | | |
| Name | | | State or Other Jurisdiction of Incorporation |
| J2 Global Australia Pty Ltd | | | Australia | |
| j2 Global Canada, Inc. | | | Canada | |
| | | | |
| Ekahau Oy | | | Finland | |
| Ziff Davis Performance Marketing Private Limited | | | India | |
| Electric Mail (Ireland) Limited | | | Ireland | |
| j2 Global Holdings Limited | | | Ireland | |
| j2 Global Ireland Limited | | | Ireland | |
| Ziff Davis Ireland Limited | | | Ireland | |
| | | | |
| Serinus42 B.V. | | | Netherlands | |
| | | | |
| | | | |
| J2 Global UK Limited | | | United Kingdom | |
| Livedrive Internet Limited | | | United Kingdom | |
| | | | |
| | | | |
| Ziff Davis International Ltd. | | | United Kingdom | |
| BabyCenter, LLC | | | Delaware, United States | |
| DW Prime Holdings Inc. | | | Delaware, United States | |
| Ekahau, Inc. | | | Delaware, United States | |
| Everyday Health, Inc. | | | Delaware, United States | |
| Everyday Health Media, LLC | | | Delaware, United States | |
| Humble Bundle, Inc. | | | Delaware, United States | |
| IGN Entertainment, Inc. | | | Delaware, United States | |
| J2 Martech Corp. | | | Delaware, United States | |
| | | | |
| | | | |
| J2 Global Ventures, LLC | | | Delaware, United States | |
| J2 Web Services, Inc. | | | Delaware, United States | |
| | | | |
| Mashable, Inc. | | | Delaware, United States | |
| Offers.com, LLC | | | Delaware, United States | |
| OnTargetJobs, Inc. | | | Delaware, United States | |
| RetailMeNot, Inc. | | | Delaware, United States | |
| SEOMoz, Inc | | | Delaware, United States | |
| SpiceWorks, Inc. | | | Delaware, United States | |
| ThreatTrack Security Holdings, Inc. | | | Delaware, United States | |
| Ziff Davis, LLC | | | Delaware, United States | |
| Ziff Davis Performance Marketing, Inc. | | | Delaware, United States | |
| Mudhook Marketing, Inc. | | | Florida, United States | |
| NetProtect, Inc. | | | Florida, United States | |
| Prime Education, LLC | | | Florida, United States | |
| ThreatTrack Security, Inc. | | | Florida, United States | |
| | | | |
| MedPage Today, L.L.C. | | | New Jersey, United States | |
| Excel Micro, LLC | | | Pennsylvania, United States | |
| | | | |
| Ookla, LLC | | | Washington, United States | |
| Root Wireless, Inc. | | | Washington, United States | |