| Skutor Educational Services Limited | Education | 2020 |
| Sky Blue Consultants Limited | Professional & scientific | 2011 |
| Sky Blue Partners Limited | Professional & scientific | 2011 |
| Sky Grid Innovations Ltd | Financial services | 2025 |
| Skye Libby Foundation | Professional & scientific | 2012 |
| Skye Tech Systems Ltd | Information & communication | 2025 |
| Skyflip Limited | Information & communication | 2006 |
| Skyline (Cressex Road) Management Company Limited | Households | 2008 |
| Skymax Star Trading Worldwide Ltd | Wholesale & retail | 2024 |
| SL Global Consulting Group LLP | | 2023 |
| SL Global Consulting Ltd | Information & communication | 2023 |
| Slejens Holding Ltd | Real estate | 2020 |
| Sliced Perfection Ltd | Hospitality | 2025 |
| Slpg Limited | Education | 2019 |
| SLS 18 Limited | Construction | 2024 |
| SM Coding Solutions Ltd | Professional & scientific | 2019 |
| SM Fortunes Ltd | Real estate | 2023 |
| Small Media Large Ltd | Professional & scientific | 2019 |
| Smart Co-Living Ltd | Real estate | 2018 |
| Smart Compliance AML Limited | Other services | 2024 |
| Smart IT Providers Ltd | Information & communication | 2008 |
| Smart Revenue Optimisation Ltd | Professional & scientific | 2020 |
| Smart Strength Club Ltd | Arts & recreation | 2025 |
| Smartext Limited | Education | 2016 |
| Smartsteps Business Support Ltd | Professional & scientific | 2026 |
| Smcloud Services Limited | Information & communication | 2020 |
| Smileys Childcare Agency Limited | Administrative & support | 2007 |
| Smiths Berkshire Services Ltd | Wholesale & retail | 2026 |
| Smithstack AI Ltd | Information & communication | 2026 |
| SML Financials Ltd | Real estate | 2012 |
| Smll Limited | Information & communication | 2017 |
| Smrithi Consultancy Ltd | Professional & scientific | 2020 |
| SMZ Motor Ltd | Wholesale & retail | 2025 |
| SN8 Limited | Professional & scientific | 2009 |
| Snaffle Cafe Limited | Hospitality | 2025 |
| Snake Bill Limited | Professional & scientific | 2025 |
| Snap That Photo Ltd | Information & communication | 2015 |
| Snow Monkey Brands Ltd | Administrative & support | 2020 |
| Snowball Automations Ltd | Information & communication | 2023 |
| Snowdon Corporation Ltd | Professional & scientific | 2011 |
| Snug Network Limited | Construction | 2019 |
| Snugleaf Limited | Wholesale & retail | 2025 |
| Snuk Holdings Ltd | Administrative & support | 2021 |
| SO Sorry Group Ltd | Wholesale & retail | 2023 |
| SO3C Ltd. | Construction | 2021 |
| Sochacki Steel Doors Ltd | Construction | 2025 |
| Softar Consulting Limited | Information & communication | 2014 |
| Software Productions Ltd | Information & communication | 2011 |
| Sognokasa Ltd | Real estate | 2024 |
| Sohaa Limited | Information & communication | 2023 |
| Soigne Consulting Ltd | Administrative & support | 2022 |
| Solar Ready Limited | Information & communication | 2011 |
| Solar Sprinkler Systems Ltd | Other services | 2024 |
| Solarbotanic Trees Ltd | Professional & scientific | 2022 |
| Solarfire Systems Limited | Construction | 2013 |
| Solasta Innovation (Capital) Limited | Financial services | 2024 |
| Solertia Ltd | Professional & scientific | 2017 |
| Solid Design and Management Ltd | Construction | 2026 |
| Solomon Security and Event Solutions Limited | Transport & logistics | 2020 |
| Solutions LDN Limited | Professional & scientific | 2019 |
| Solutions Makers Ltd | Professional & scientific | 2024 |
| Solutions Shared Limited | Information & communication | 2007 |
| Somewhere Social Ltd | Hospitality | 2024 |
| Sonderwell Bidco Limited | Financial services | 2021 |
| Sonderwell Finco Limited | Financial services | 2021 |
| Sonderwell Topco 2 Limited | Financial services | 2026 |
| Sonja Stevanovic Limited | Professional & scientific | 2025 |
| Sonning Wealth Advice Limited | Financial services | 2017 |
| Sophicvet Consulting Limited | Financial services | 2017 |
| Sophun Games Limited | Information & communication | 2022 |
| Sorano Kitchens Ltd | Wholesale & retail | 2026 |
| Sorelle Support Limited | Health & social care | 2011 |
| Soujanya Consultancy Services Limited | Information & communication | 2014 |
| Soulfresh UK Limited | Financial services | 2018 |
| Soundbridge Live Ltd | Information & communication | 2025 |
| Sounds Delightful Ltd | Wholesale & retail | 2020 |
| South Drive Residents Association Limited | Other services | 2002 |
| South Lake (Woodley) Management Company Limited | Households | 1973 |
| Southcote Manor Limited | Households | 1983 |
| Southern Counties Landscapes Limited | Administrative & support | 1997 |
| Southern Mini Piling Contractors Ltd | Construction | 2018 |
| Southern Valley Homes Ltd | Construction | 2014 |
| Southlake Angling Society | Agriculture & fishing | 2010 |
| Sova Consulting Ltd | Administrative & support | 2012 |
| Sovereign Mews (Ascot) Management Company Limited | Households | 2012 |
| SP Data Solutions Ltd | Information & communication | 2024 |
| Space Supported Housing C.I.C. | Real estate | 2019 |
| Space Ways Technologies Trademark (Swtt) LLP | | 2023 |
| Space Ways Technologies UK Ltd | Information & communication | 2024 |
| Sparc-E Limited | Information & communication | 2014 |
| Sparkle Cleaning Group Ltd | Administrative & support | 2026 |
| Sparkle Info Ltd | Information & communication | 2014 |
| Sparkpost Studio Ltd | Professional & scientific | 2025 |
| Sparrows Solar Ltd | Construction | 2025 |
| Spartan Events Buisness Ltd | Hospitality | 2023 |
| Specialist Education Transport Limited | Transport & logistics | 2019 |
| Specialist Project Delivery Ltd | Professional & scientific | 2025 |
| Spectrum Graphics UK Ltd | Administrative & support | 2002 |
| Spencers Wood Management Company Limited | Households | 2002 |
| Spenmac UK Limited | Construction | 2011 |