| Since Private Ltd | Health & social care | 2018 |
| Single USE Surgical Limited | Manufacturing | 2001 |
| Singleton Landwork Limited | Administrative & support | 2003 |
| SIP Kits UK Ltd | Construction | 2020 |
| Sirengold Entertainments Ltd | Arts & recreation | 2016 |
| Sis-Seating Limited | Manufacturing | 2015 |
| Siteglass Limited | Construction | 2000 |
| Sitetech Irrigation Limited | Agriculture & fishing | 2024 |
| SJ Bespoke Fabrication Limited | Manufacturing | 2021 |
| SJ Garages Ltd | Construction | 2024 |
| SJ Legal Limited | Professional & scientific | 2009 |
| SJ Prescott Ltd | Construction | 2011 |
| SJG International Transport Limited | Transport & logistics | 2026 |
| SJK Roofing Ltd | Construction | 2026 |
| SJS Sasa Ltd | Transport & logistics | 2017 |
| SK Autobahn Limited | Wholesale & retail | 2017 |
| Skapandi Transport Ltd | Transport & logistics | 2019 |
| Skin Devotion (UK) Ltd | Health & social care | 2018 |
| Skin Trader Ltd | Wholesale & retail | 2019 |
| Skinergise Limited | Other services | 2019 |
| Skinhealth Aesthetics Limited | Health & social care | 2016 |
| SKS Welding Limited | Manufacturing | 2017 |
| Sky Touch Windows & Glazing Ltd | Construction | 2018 |
| Skyn Bakery Ltd | Manufacturing | 2020 |
| Skyoptics Ltd | Professional & scientific | 2015 |
| SL Engineering Designs Limited | Professional & scientific | 2023 |
| Slaby Ltd | Transport & logistics | 2018 |
| Slacks Farm Butchers Limited | Wholesale & retail | 1987 |
| Slate Facilities Management Limited | Professional & scientific | 2025 |
| Slater Lane Ltd | Construction | 2024 |
| SLE Online Business Solutions Ltd | Professional & scientific | 2025 |
| Sleepy Hollow Bedroom Centre Ltd | Wholesale & retail | 2015 |
| Slick Home Delivery & Installation Limited | Manufacturing | 2021 |
| Slide Robes Direct Limited | Manufacturing | 2016 |
| Slim Gym Limited | Arts & recreation | 2025 |
| SM Consultantancy Ltd | Professional & scientific | 2026 |
| SM Engineering & Surveying Services Ltd | Professional & scientific | 2026 |
| Small Jobs Done Limited | Manufacturing | 2025 |
| Smart Abode Limited | Extraterritorial | 2014 |
| Smart DGT Limited | Manufacturing | 2024 |
| Smart Fire and Security Ltd | Construction | 2024 |
| Smart Food & Wine Limited | Wholesale & retail | 2016 |
| Smart HUT Ltd | Wholesale & retail | 2024 |
| Smart Print & Labels (Sales) Limited | Wholesale & retail | 2004 |
| Smart Seal Energy Solutions Limited | Construction | 2025 |
| Smart Spend Construction Ltd | Construction | 2025 |
| Smart Techs (NW) Ltd | Wholesale & retail | 2019 |
| Smartclear Projects Limited | Information & communication | 1993 |
| Smash Feast Ltd | Hospitality | 2025 |
| Smgolf Ltd. | Arts & recreation | 2016 |
| SMH Electrical Ltd | Construction | 2015 |
| Smileplus Extra Ltd | Health & social care | 2025 |
| Smith's Courier Services Limited | Transport & logistics | 2016 |
| Smith's Street Food Ltd | Hospitality | 2024 |
| Smiths Car Sales of Staffordshire Limited | Wholesale & retail | 2014 |
| Smokies BBQ Restaurant Limited | Hospitality | 2018 |
| Smooth Brew Ltd | Hospitality | 2023 |
| Smooth Coat Plastering Ltd | Construction | 2013 |
| SMW Property Ltd | Construction | 2015 |
| Snackboxx Ltd | Wholesale & retail | 2025 |
| Snax Emporium Ltd | Wholesale & retail | 2017 |
| SNB London Ltd | Professional & scientific | 2019 |
| SNM Logistics Ltd | Wholesale & retail | 2025 |
| Snodland Pizza Ltd | Hospitality | 2015 |
| Snowdon Recruitment Limited | Administrative & support | 2017 |
| Snowgate Properties Limited | Financial services | 1999 |
| Snowy Office Ltd | Information & communication | 2026 |
| Soak Interiors Ltd | Wholesale & retail | 2020 |
| Social Housing Design Limited | Construction | 2025 |
| Social Muse Content Ltd | Information & communication | 2025 |
| Social ROX Limited | Administrative & support | 2022 |
| Socialhootz Ltd | Information & communication | 2011 |
| Socialnorth Ltd | Administrative & support | 2023 |
| Societal Group Limited | Real estate | 2021 |
| Societas Rosicruciana in Anglia Ltd | Information & communication | 2024 |
| Socius - IT Limited | Information & communication | 2013 |
| Solacexis Ltd | Professional & scientific | 2011 |
| Solar Roofing Company Group Limited | Financial services | 2025 |
| Solargen Energy Ltd | Construction | 2010 |
| Solargen Holdings Limited | Financial services | 2020 |
| Sole Consulting Ltd | Administrative & support | 2013 |
| Solera Estates Ltd | Real estate | 2022 |
| Solid Bond Capital Limited | Professional & scientific | 2015 |
| Solid K9 Security Services Limited | Administrative & support | 2019 |
| Solid Visuals Ltd | Wholesale & retail | 2025 |
| Solids Removal Systems Limited | Construction | 2004 |
| Solis Studio Boutique Ltd. | Wholesale & retail | 2026 |
| Solution Proposals Europe Limited | Information & communication | 2008 |
| Solutus Advisors Limited | Financial services | 2010 |
| Somos Accounting Limited | Professional & scientific | 2018 |
| Sonic Fire and Security Limited | Construction | 2000 |
| Sonitech Holdings Limited | Financial services | 2024 |
| Sonitech Systems Limited | Administrative & support | 1991 |
| Sonya Brow Bar Ltd | Other services | 2023 |
| Sophia Amiyah MAE Property Holdings Limited | Real estate | 2021 |
| Sophie's Flower POT Ltd | Wholesale & retail | 2023 |
| Sophie's Kitchen Ltd | Hospitality | 2019 |
| Soul Focus Wellbeing Ltd | Education | 2026 |
| Source Design and Build UK Ltd | Construction | 2026 |
| South East Utility Services Ltd | Construction | 2019 |