| SOOM | |
| SoPost Ltd | |
| Sorce Ltd | Berkshire |
| Sorex Sensors Ltd | |
| Sorrento Networks International, Inc. | Belfast |
| Sorsis Ltd | Norfolk |
| Sorted Group Ltd | |
| Sorted Technologies Ltd | |
| Sortera Bio Ltd | |
| Sortlist | |
| SOS Group Ltd | Tyne and Wear |
| SOS Marketing | |
| SOS Systems Ltd | West Sussex |
| SOSWEB | Kent |
| Sota Solutions Ltd | Kent |
| SOtechnology | Bedfordshire |
| Soto Digital Ltd | Bristol |
| Sound and Visual Systems Ltd | Devon |
| Sound Solution Consultants Ltd | |
| Sounds Like Design | |
| Souqbox | |
| Source BioScience | |
| Source Code Control Ltd | |
| Source Creative Ltd | Lancashire |
| Source Design | Shropshire |
| Source Doctor Ltd | Staffordshire |
| Source Internet Development Ltd | Leicestershire |
| Source Software Ltd | Vale of Glamorgan |
| Source UPS Ltd | |
| SourceDogg | |
| SourceGuardian Ltd | County Durham |
| Sourcemotion Ltd | Greater Manchester |
| Sourcery | |
| Sourcing House Ltd | Berkshire |
| South Design Ltd | |
| South Devon Colleve | |
| South East Labels | West Sussex |
| South Eastern Regional College | |
| South Essex Apple Link | Essex |
| South Gloucestershire and Stroud College | |
| South Rhins Web Design | |
| South Tyneside College | |
| South Wales Web Solutions | Bridgend |
| South West College | |
| South West Communications Group Ltd | Devon |
| South West Grid for Learning Trust Ltd | |
| South West Systems UK Ltd | Devon |
| Southcastweb | |
| Southdown House Software Ltd | Surrey |
| Southern Business Communications Ltd | |