| SNC Transport Limited | Transport & logistics | 2021 |
| SNO Limited | Administrative & support | 2006 |
| Snooze Esports Ltd | Arts & recreation | 2025 |
| Snow Centre Car Wash Limited | Other services | 2014 |
| Snowcentres Limited | Arts & recreation | 2007 |
| Snpf Properties Ltd | Real estate | 2021 |
| Soar Beyond Limited | Information & communication | 2006 |
| Social Squirrel Ltd | Professional & scientific | 2016 |
| Social Work Plus Limited | Administrative & support | 2015 |
| Socially Content Ltd | Professional & scientific | 2023 |
| Sodark Care Ltd | Health & social care | 2015 |
| Sodylux Ltd | Wholesale & retail | 2026 |
| SOE Sisters Ltd | Wholesale & retail | 2022 |
| Sofcoms Limited | Information & communication | 1978 |
| Soft Pressure Herts Ltd | Construction | 2026 |
| Sojbol Ltd | Professional & scientific | 2026 |
| Sojka Welding Ltd | Other services | 2026 |
| Solarguys Limited | Manufacturing | 2022 |
| Solas Electrical Ltd | Construction | 2017 |
| Sole Sister Limited | Extraterritorial | 1995 |
| Sole Trader Limited | Extraterritorial | 2011 |
| Soled OUT Limited | Extraterritorial | 1995 |
| Solertium Ltd | Administrative & support | 2022 |
| Solid Principles Ltd | Information & communication | 2015 |
| Solly Street Management Company Limited | Households | 2007 |
| Solo Fit Ltd | Arts & recreation | 2024 |
| Solomons Systems Limited | Information & communication | 2018 |
| Solutionsra Ltd | Professional & scientific | 2017 |
| Soluvet Ltd | Administrative & support | 2018 |
| Somerhill Green Management Company Limited | Households | 2015 |
| Somers Print & Design Ltd | | 2008 |
| Sonclair Ltd | Professional & scientific | 2025 |
| Songprompter Ltd | Information & communication | 2026 |
| Sonlex Accounts Ltd | Professional & scientific | 2026 |
| Sophie Cattermole Communications Limited | Professional & scientific | 2022 |
| Sorin Decor Ltd | Construction | 2025 |
| SOS Car Automotive Center Ltd | Wholesale & retail | 2014 |
| SOS Fitted Bedrooms Limited | Manufacturing | 2015 |
| Soul Real Estate Ltd | Financial services | 2025 |
| Soulsshoes Ltd | Wholesale & retail | 2026 |
| Sound Recording Technology Ltd | Information & communication | 2012 |
| South Facing Geese Limited | Professional & scientific | 2012 |
| South Hill Church (Hemel Hempstead) | Other services | 2010 |
| South Hills Properties Ltd | Real estate | 2025 |
| South West Diamonds Ltd | Real estate | 2025 |
| Southcote Consultants Ltd | Information & communication | 2011 |
| Southern Building Contracts Ltd | Construction | 2016 |
| Southern Parks Limited | Administrative & support | 2012 |
| Southern Plant Solutions (Hire) Ltd | Manufacturing | 2021 |
| Southern Plant Solutions Ltd | Manufacturing | 2014 |
| Souvlaki Station Bedford Ltd | Hospitality | 2023 |
| Souvlaki Station Dunstable Ltd | Hospitality | 2025 |
| Sovea Services Ltd | Administrative & support | 2019 |
| Sovereign Associates Limited | Professional & scientific | 2011 |
| Sovereign Risk Ltd | Financial services | 2026 |
| Spa Mobile Repairs Ltd | Wholesale & retail | 2020 |
| Space Holdings Limited | Real estate | 2024 |
| Space IT Ltd | Information & communication | 2025 |
| Spacestor Limited | Extraterritorial | 2012 |
| Sparkle EE Ltd | Administrative & support | 2025 |
| Sparkse Ltd | Information & communication | 2007 |
| Spartacus Construction Limited | Construction | 2024 |
| Special Wear Trustees Limited | Administrative & support | 2021 |
| Special Wear UK Limited | Administrative & support | 2000 |
| Special Welding Vizcam Limited | Construction | 2016 |
| Specialist Care Services (Bucks) Ltd | Health & social care | 2024 |
| Spectrum Healthcare Management Ltd | Professional & scientific | 2008 |
| Speed Solutions Consultancy Ltd | Professional & scientific | 2023 |
| Speedy TST Logistic Ltd | Transport & logistics | 2021 |
| Spellbound Computer Co. Ltd. | Information & communication | 2010 |
| Spencer Chase Ltd | Administrative & support | 2026 |
| Spherenode Group Ltd | Information & communication | 2024 |
| Spiamuoln Ltd | Information & communication | 2003 |
| Spice Bitez Ltd | Hospitality | 2026 |
| Spice Brickwork Ltd | Construction | 2026 |
| Spice Realm Ltd | Wholesale & retail | 2022 |
| Spice River Ltd | Hospitality | 2019 |
| Spiliada Ltd | Financial services | 2022 |
| Spindrift Park (Pagham) Residents Management Company Limited | Real estate | 2023 |
| Spires View (Old Marston) Management Company Limited | Households | 2025 |
| Spirewood Grange (Rowbarrow) Management Company Limited | Households | 2025 |
| Spirit SD Limited | Information & communication | 2015 |
| Spiro Health Care Services Ltd | Health & social care | 2022 |
| Spital Field Holdings Ltd | Households | 2025 |
| SPK Mortgages Ltd. | Financial services | 2017 |
| Splash Digital Limited | Manufacturing | 2011 |
| Splendour Consulting Limited | Professional & scientific | 2012 |
| Spoon Guru Limited | Information & communication | 2014 |
| Sportics Group Limited | Information & communication | 2025 |
| Sporting Kids Ltd | Arts & recreation | 2018 |
| Sportolotto Limited | Information & communication | 2025 |
| Sportopia Coaching Ltd | Education | 2025 |
| Spotless Team Limited | Administrative & support | 2015 |
| Spotless Team Maintenance Ltd | Administrative & support | 2019 |
| Spotless Team Window Cleaners Ltd | Administrative & support | 2026 |
| Spotlight Electrical Services Ltd | Construction | 2019 |
| Spotlight Youth Theatre Ltd | Arts & recreation | 2023 |
| Spoton Energy UK Limited | Mining & quarrying | 2021 |
| Spread a Smile | Health & social care | 2013 |
| Spring Court (Peterborough) Limited | Households | 2003 |