| SO Integrations | |
| SO Web Ltd | Surrey |
| SO... Digital Communications Ltd | |
| SO53 | Hampshire |
| Soak Digital Ltd | Norfolk |
| SoAmpli | |
| Soap Media | Lancashire |
| Soapbox Digital Media | |
| Soar Enterprises Online Ltd | |
| Soar Tech Ltd | |
| Soar Tech Ltd | |
| SOAS University of London | Greater London |
| SoBold | |
| SoBytes | |
| Social Buzzing | |
| Social Hunt | |
| Social Media Marketing | Cambridgeshire |
| Social Nest UK | |
| Social Value Portal | |
| Socialable | East Sussex |
| SocialB Ltd | |
| Socialectric | |
| SocialFactory.net | Greater London |
| Sociality.io Ltd | Greater London |
| Socialvar | |
| Society for Underwater Technology | Greater London |
| SoCreative Studio | |
| SOD-IT | |
| sofaDEVE | |
| Sofant Technologies Ltd | |
| Soficus Ltd | |
| Soft House | |
| Soft Innovation Ltd | |
| Soft Options (Systems) Ltd | West Yorkshire |
| Soft Rock Software | Bristol |
| Soft-Lutions Ltd | Bedfordshire |
| Softabacus (UK) Ltd | Bristol |
| Softaims | |
| SoftBank Vision Fund | Greater London |
| SoftBlues Solutions Ltd | |
| Softcat plc | Buckinghamshire |
| SoftClo | |
| Softcraft Computer Services Ltd | Norfolk |
| Softech 2000 Ltd | Buckinghamshire |
| Softek Software Ltd | South Yorkshire |
| SoftElegance | |
| Soften | |
| Softexpoit | |
| SoftForge Ltd | |
| SoftIron Ltd | |