| Studio 42 Ltd | Wholesale & retail | 2024 |
| Studio Core LLP | | 2024 |
| Studio Dabouni Ltd | Arts & recreation | 2021 |
| Studio Right Angle Ltd | Information & communication | 2024 |
| Studio Statik Ltd | Professional & scientific | 2022 |
| Studio Sunday Ltd | Information & communication | 2024 |
| Studio VDC Ltd | Manufacturing | 2025 |
| Studio Vedi Limited | Professional & scientific | 2019 |
| Studiotrap Limited | Other services | 2015 |
| Study UK Consultants Ltd | Education | 2018 |
| Stuffed 23 Ltd | Hospitality | 2022 |
| Stvchicken Ltd | Hospitality | 2019 |
| Style Eventz Ltd | Arts & recreation | 2025 |
| Style Oasis Ltd | Wholesale & retail | 2024 |
| Suavo World Limited | Wholesale & retail | 2020 |
| Subjam Limited | Information & communication | 2015 |
| Sublime Active Ltd | Wholesale & retail | 2020 |
| Subtle African Print Limited | Manufacturing | 2024 |
| Subtle Healthcare Limited | Health & social care | 2022 |
| SUE Rider Management Ltd | Administrative & support | 2009 |
| Sufficient Social Care Ltd | Health & social care | 2023 |
| Sugarloaf Consulting Ltd | Professional & scientific | 2023 |
| Sujana Healthcare Services Ltd | Health & social care | 2024 |
| Sujana Holdings Limited | Real estate | 2025 |
| Sukawatee Takeaway Stevenage Old Town Ltd | Hospitality | 2024 |
| Suku Construction Ltd | Construction | 2026 |
| Summit Decor Ltd | Construction | 2023 |
| Summit Global Resources Ltd | Financial services | 2021 |
| Summit Refurbishments Ltd | Construction | 2018 |
| Summitcore Ltd | Administrative & support | 2026 |
| Sun Booth Limited | Other services | 2019 |
| Sun Booth Sister Limited | Other services | 2024 |
| Sun Clinic Group Ltd | Other services | 2020 |
| Sun True Energy Ltd | Construction | 2026 |
| Sunbeams Preschool Ltd | Education | 2025 |
| Sunningdale 74 Limited | Other services | 2022 |
| Sunningfields Investment Co. Limited | Real estate | 1955 |
| Sunny One Pro Limited | Real estate | 2024 |
| Sunny Pro Limited | Real estate | 2020 |
| Sunnypowers Limited | Information & communication | 2003 |
| Sunreign Ltd | Information & communication | 2014 |
| Sunshine Creative Productions Ltd | Information & communication | 2025 |
| Sunway Technologies Ltd | Information & communication | 2025 |
| Super Simple Limited | Wholesale & retail | 2021 |
| Super Tenants LLP | | 2022 |
| Super-Beverages Limited | Manufacturing | 2018 |
| Supra Digital Group Limited | Financial services | 2022 |
| Supra Digital Limited | Information & communication | 2023 |
| Supreme Caring Services Limited | Public administration | 2024 |
| Supreme Gardens Limited | Administrative & support | 2021 |
| Supreme Interiors Limited | Construction | 2016 |
| Supreme Paint Works Ltd | Wholesale & retail | 2019 |
| Sure Safe Manpower Limited | Construction | 2013 |
| Sureset Construction Ltd | Construction | 2024 |
| Surkit Limited | Manufacturing | 2010 |
| Surrey London Kent Property Services Ltd | Construction | 2023 |
| Surveyor Engine Ltd | Information & communication | 2024 |
| Sustain International OIL Company Limited | Wholesale & retail | 2023 |
| Sustainable Polythene Limited | Financial services | 2021 |
| Sustainable Tech 4 Good Group Ltd | Other services | 2020 |
| SV EOT Trustees Limited | Financial services | 2025 |
| Svbodykits Ltd | Wholesale & retail | 2026 |
| Svondo Artistry Ltd | Arts & recreation | 2018 |
| SVS Location Services Limited | Information & communication | 2024 |
| Svsm Limited | Health & social care | 2023 |
| Swains Logistics & Distribution Ltd | Transport & logistics | 2023 |
| Swains Technology Ltd | Information & communication | 2021 |
| Swale Capital Limited | Information & communication | 2023 |
| Swan Academy Community CIC | Education | 2026 |
| Swan Academy Limited | Arts & recreation | 2017 |
| Swanbio Therapeutics Limited | Professional & scientific | 2017 |
| Sweet and Sarwa Ltd | Wholesale & retail | 2025 |
| Sweet O'Clock Limited | Hospitality | 2016 |
| Sweet T'S Bakery Limited | Hospitality | 2019 |
| Sweet Vibe Events Limited | Arts & recreation | 2026 |
| Sweh Group Ltd | Hospitality | 2025 |
| Swiftlyn Ltd | Administrative & support | 2025 |
| Swiftmed Reports Limited | Health & social care | 2025 |
| Swinghub Limited | Information & communication | 2022 |
| Swordstrand Limited | Wholesale & retail | 1999 |
| SXD Leadership Communications Ltd | Professional & scientific | 2011 |
| SYB Studios Ltd | Professional & scientific | 2025 |
| Symbol London Ltd | Information & communication | 2019 |
| Sympatra Ltd | Administrative & support | 2024 |
| Synergy Climate Solutions Group Hvac Ltd | Administrative & support | 2025 |
| Synergy Electrical Systems Ltd | Construction | 2026 |
| Syntrofia Care Ltd | Health & social care | 2026 |
| Synvia Limited | Health & social care | 2025 |
| Systems International Limited | Real estate | 1987 |
| Szuvorov Ltd | Professional & scientific | 2017 |
| T & M of London Limited | Construction | 2013 |
| T C E Property Maintenance Ltd | Construction | 2019 |
| T C Rigging & Construction Ltd | Construction | 2014 |
| T Kavanagh Consultants Ltd | Professional & scientific | 2018 |
| T L Brignell & Co Limited | Professional & scientific | 2023 |
| T Wise Consulting Limited | Professional & scientific | 2010 |
| T&I Cafe Ltd | Hospitality | 2021 |
| T. Nevill & Co. (Engineers) Limited | Construction | 1972 |
| T. Nevill Properties Limited | Real estate | 2006 |
| T.A.Construction Limited | Construction | 2015 |