| Stone a Construction Ltd | Manufacturing | 2022 |
| Stonebloom Limited | Hospitality | 2025 |
| Stonegateapps Ltd | Information & communication | 2025 |
| Stoneline Limited | Real estate | 2025 |
| Storm Construction Ltd | Construction | 2025 |
| Stormone Ltd | Wholesale & retail | 2022 |
| STR Interior Finishers Ltd | Construction | 2021 |
| Strafford Court Residents Association Limited | Households | 1997 |
| Stream Therapy Service Ltd | Health & social care | 2021 |
| Street Smart Vehicle Repairs Ltd | Wholesale & retail | 2021 |
| Streetkids Ventures Ltd | Manufacturing | 2025 |
| Strongman Project Services Ltd | Professional & scientific | 2012 |
| Stuart Buxton Limited | Professional & scientific | 2015 |
| Stuart Ingram Construction Limited | Construction | 2009 |
| Stuart Ward Electrical Limited | Construction | 2018 |
| Studham Properties Ltd | Real estate | 2024 |
| Studio Anton Ltd | Professional & scientific | 2020 |
| Studio CAD Projects Ltd | Professional & scientific | 2014 |
| Studio Stylescape Ltd | Professional & scientific | 2025 |
| Studley Road (Management) Limited | Households | 1988 |
| Study Cruise PVT Ltd | Transport & logistics | 2021 |
| Style & Spark Ltd. | Other services | 2018 |
| Stylesbypurple Ltd | Manufacturing | 2026 |
| Suba Aviation Limited | Other services | 2022 |
| Subechya and Associates Ltd | Wholesale & retail | 2024 |
| Subtle Links Ltd. | Transport & logistics | 2020 |
| Success Advisory Limited | Professional & scientific | 2020 |
| Success on Demand Limited | Wholesale & retail | 2021 |
| Sudwest Ltd | Transport & logistics | 2018 |
| Sugar Real Estate Ltd | Real estate | 2020 |
| Sugar Town Ltd | Hospitality | 2025 |
| Suggawala Transport Ltd | Transport & logistics | 2026 |
| Suitcase Limited | Administrative & support | 2016 |
| Suitcase Travel Limited | Administrative & support | 2020 |
| Sullivans a Cuts Limited | Other services | 2015 |
| Sultan Barbers Dunstabl Limited | Other services | 2023 |
| Summerfield Garage Doors Limited | Construction | 2015 |
| Sun Taverns Limited | Professional & scientific | 1973 |
| Sun Trap Tanning LB Limited | Other services | 2012 |
| Sundon Car Wash Limited | Other services | 2019 |
| Sunita Properties Ltd | Real estate | 2024 |
| Sunmoon Consultancy Limited | Information & communication | 2017 |
| Sunny G Motors Ltd | Manufacturing | 2025 |
| Sunrise Practice Limited | Health & social care | 2019 |
| Sunshine Care Services Ltd | Health & social care | 2018 |
| Super Seven Foods Limited | Wholesale & retail | 2021 |
| Super Seven Private Limited | Wholesale & retail | 2021 |
| Superfine Tapes Company Limited | Manufacturing | 1962 |
| Supply Site Ltd | Wholesale & retail | 2019 |
| Supplyessentials Ltd | Wholesale & retail | 2023 |
| Supreme Rigging Ltd | Construction | 2025 |
| SUR Construction Services Limited | Construction | 2017 |
| SUR Engineering Services Limited | Construction | 2014 |
| Surdu Tech Ltd | Information & communication | 2024 |
| Surechoice Care Limited | Health & social care | 2022 |
| Surelec Ltd | Construction | 2014 |
| Surma (UK) Limited | Real estate | 2003 |
| Surrey Imperial Blinds & Shutters Limited | Construction | 2020 |
| Sustainable TX Ltd | Professional & scientific | 2026 |
| Sustainnovate Ltd | Professional & scientific | 2025 |
| SW6 Kitchens & Joinery Ltd | Construction | 2022 |
| Swan Mead Limited | Administrative & support | 2018 |
| Sweeeeeetz (Events) Ltd | Hospitality | 2025 |
| Sweenys Barber Shop Limited | Other services | 2025 |
| Sweeping Wonders Limited | Administrative & support | 2025 |
| Sweet Dreams London Ltd | Manufacturing | 2025 |
| Sweetrose Care Limited | Hospitality | 2024 |
| Sweety Home Limited | Real estate | 2023 |
| Swift Cars Dunstable Limited | Transport & logistics | 2017 |
| Swift Metal Fabrications Limited | Manufacturing | 1989 |
| Swift Racing Ltd | Wholesale & retail | 2021 |
| Swiftlogisticsuk Ltd | Transport & logistics | 2020 |
| Swimming Lessons Limited | Arts & recreation | 2011 |
| Swisstech Ltd | Construction | 2014 |
| Swlm Consultancy Limited | Information & communication | 2015 |
| Swordluck Limited | Manufacturing | 2022 |
| Sylhet Sweets Limited | Wholesale & retail | 2020 |
| Sylhet Taste Limited | Hospitality | 2023 |
| Symology Limited | Information & communication | 1983 |
| Symology Trustees LLP | | 2014 |
| Symphony Controls Limited | Manufacturing | 2026 |
| Syncsol Ltd | Wholesale & retail | 2023 |
| Systema Consulting Limited | Professional & scientific | 2026 |
| Systematic Selection Limited | Administrative & support | 2012 |
| Szubert Carpentry Services Limited | Construction | 2016 |
| T & R Development & Construction Limited | Construction | 2025 |
| T & R Management Services Limited | Hospitality | 2024 |
| T & R Property Investments Limited | Real estate | 2025 |
| T & S Healthcare Services Limited | Health & social care | 2021 |
| T Allen Design Limited | Professional & scientific | 2011 |
| T C Classic Services Ltd | Wholesale & retail | 2019 |
| T C Feeds & Tack Haven Limited | Wholesale & retail | 2004 |
| T Gilmartin Limited | Construction | 2001 |
| T K George Limited | Health & social care | 2010 |
| T Lyons Construction Limited | Construction | 2001 |
| T N Electrical Contractors Limited | Construction | 2010 |
| T W Collection Ltd | Real estate | 2020 |
| T&B Sons Limited | Hospitality | 2020 |
| T&E Groundworks&Civil Engineering Ltd | Construction | 2025 |
| T&J Construction Ltd | Construction | 2017 |