| Storm Technologies | Hertfordshire |
| STORM Therapeutics Ltd | |
| Storm Website Design | Aberdeen |
| Storm3 | |
| StormCloud Games Ltd | |
| StormHarvester | Belfast |
| Stormnet Media Ltd | Worcestershire |
| Stortech Electronics Ltd | Essex |
| Story Agency | |
| StoryFutures | |
| StoryStream | Greater London |
| Stotles | |
| Stovin Advertising | |
| Stox | Gibraltar |
| Straal Ltd | |
| Strafe Ltd | Nottinghamshire |
| Straker Systems Ltd | |
| STRANDcreative.com | |
| Strange | Dorset |
| Stranmillis University College | |
| Strata Consulting Ltd | |
| Stratech | |
| Strategic Blue | |
| Strategic Maintenance Planning Ltd | Wiltshire |
| Strategic Resources European Recruitment Consultants | |
| Strategically Digital Marketing Ltd | |
| Strategies | Hampshire |
| StrategiQ Group Ltd | Greater London |
| Strategy 4 AI | |
| Strategy Plus (UK) Ltd | West Midlands |
| Stratford College London | |
| Strathspey Capital Ltd | |
| Stratis Platform | |
| Stratos Creative Ltd | |
| Stratosvir Ltd | |
| Stratton & English Software Ltd | South Yorkshire |
| Stratum | |
| Strawberrysoup Ltd | West Sussex |
| Strawdog Studios | Derbyshire |
| Stream Studio Ltd | Leicestershire |
| Stream Web | Leicestershire |
| Streamba | Aberdeen |
| streamGo | Greater Manchester |
| Streaming Video Provider | Greater London |
| Streaming Wizard Ltd | Warwickshire |
| StreamSoft Development Ltd | |
| Streetbees | |
| Streets Heaver | Lincolnshire |
| Strictly Business Consulting Marketing Ltd | |
| Strictly Sales & Marketing | |