| Strawberry Bars (Chelmsford) Ltd | Hospitality | 2016 |
| Strawberry Bars (Watford) Ltd | Administrative & support | 2016 |
| Strictly Sales & Marketing Limited | Administrative & support | 2009 |
| Strongandginger Ltd | Wholesale & retail | 2022 |
| Stronger Than Yesterday Ltd | Arts & recreation | 2022 |
| Strongthe Ltd | Arts & recreation | 2019 |
| Stroud Green Launderette Limited | Other services | 1953 |
| Stuart Lightband Limited | Real estate | 1936 |
| Studio Aitchay Ltd | Professional & scientific | 2025 |
| Studio Forty Limited | Professional & scientific | 2018 |
| Studio Lawrence Limited | Arts & recreation | 2021 |
| Studio MAX Italiaander Ltd | Information & communication | 2023 |
| Studio Morph Limited | Professional & scientific | 2024 |
| Studio Nord Ltd | Professional & scientific | 2022 |
| Studio Piqasso Limited | Information & communication | 2023 |
| Study Care Limited | Education | 2008 |
| Sturdy Evolution Developments Ltd | Construction | 2014 |
| Sublime Concepts Ltd | Professional & scientific | 2023 |
| Subzero Detailing Ltd | Wholesale & retail | 2025 |
| SUC. EXC. UK. Ltd | Construction | 2009 |
| Sugar Rays Limited | Other services | 2010 |
| Sugarfoot Ltd | Wholesale & retail | 2019 |
| Suitebox UK Limited | Information & communication | 2019 |
| Sullington Group Ltd | Financial services | 2026 |
| Sullivan Roofing Limited | Construction | 2025 |
| Summerhill Advisory Limited | Information & communication | 2025 |
| Summit Investments Portfolio Limited | Financial services | 2019 |
| Summit Projects Holdings Limited | Financial services | 2026 |
| Summit Property Maintenance Limited | Construction | 2000 |
| Sumotherhood Productions [2] Limited | Information & communication | 2025 |
| Sums of Anarchy Maths Ltd | Wholesale & retail | 2023 |
| Sunbright Energy Ltd | Construction | 2014 |
| Sundance House Ltd | Health & social care | 2018 |
| Sundance Real Estate Limited | Real estate | 2021 |
| Sundara Natya Ltd | Education | 2026 |
| Sunday Truck Club Ltd | Hospitality | 2023 |
| Sunncamp Limited | Wholesale & retail | 1996 |
| Sunnflair Holdings Limited | Financial services | 1991 |
| Sunnflair Limited | Wholesale & retail | 1983 |
| Sunny Gummies Ltd | Wholesale & retail | 2025 |
| Sunnyb Holdings Ltd | Other services | 2023 |
| Sunnymede of Chigwell Limited | Wholesale & retail | 1999 |
| Sunnyriserenewables Ltd | Professional & scientific | 2025 |
| Suns Lifestyle Ltd | Wholesale & retail | 2019 |
| Sunstone Cars Ltd | Wholesale & retail | 2019 |
| Super Seal Sealants Ltd | Construction | 2020 |
| Super Skip Hire Ltd | Water & waste | 2021 |
| Superboost UK Ltd | Wholesale & retail | 2025 |
| Supercar Rentals Limited | Administrative & support | 2023 |
| Supercar Sourcing Events Limited | Administrative & support | 2022 |
| Supercar Sourcing Ltd | Wholesale & retail | 2016 |
| Superdinky Ltd | Wholesale & retail | 2019 |
| Superficiem Ltd | Construction | 2017 |
| Superior Tiling Limited | Construction | 2004 |
| Support Company Ltd | Construction | 2026 |
| Suprema Flooring Limited | Construction | 1997 |
| Suprema Holdings Limited | Financial services | 1998 |
| Supreme Valet Car Sales Ltd | Administrative & support | 2024 |
| Supremeklene Ltd | Administrative & support | 2017 |
| Surebuild Solutions Limited | Construction | 2020 |
| Suri Medical Limited | Health & social care | 2010 |
| Sursr Limited | Information & communication | 2025 |
| Surveying Services Global Limited | Professional & scientific | 2023 |
| Surya Lanka Rebuilding Foundation Limited | Extraterritorial | 2005 |
| Sushi Tachi Limited | Hospitality | 2024 |
| Svarn Developments Limited | Real estate | 2025 |
| Sven's Tree Services Ltd | Agriculture & fishing | 2018 |
| SW Drainage Solutions Ltd | Water & waste | 2015 |
| SW Paybuild Ltd | Professional & scientific | 2025 |
| SW Solutions (Newcastle) Limited | Information & communication | 1999 |
| Swags & Bows Limited | Wholesale & retail | 2003 |
| Swanton Road Ltd | Financial services | 2020 |
| Swarg Ltd | Households | 2022 |
| Swarvinn Impex Ltd | Wholesale & retail | 2025 |
| Swds (Group) Ltd | Water & waste | 2015 |
| Sweet Dreams Essex Limited | Wholesale & retail | 2025 |
| Swift Roofing Specialists Ltd | Construction | 2023 |
| Swimed Aquatics Ltd | Education | 2026 |
| Swishaccess Limited | Construction | 2020 |
| Switch Currency Limited | Financial services | 2022 |
| Switch Partners Ltd | Financial services | 2025 |
| SWK Contractors Ltd | Construction | 2021 |
| SX MMA CIC | Education | 2017 |
| SX Property Services Limited | Construction | 2014 |
| SXM Property Services Ltd | Construction | 2026 |
| Sybil Group Limited | Construction | 2022 |
| Sylvent Ltd | Wholesale & retail | 2025 |
| Symmetry Design Limited | Professional & scientific | 2021 |
| Synergy 7 Group Holdings Ltd | Financial services | 2023 |
| Synergy 7 Group Ltd | Construction | 1997 |
| Syrtaki Restaurant Limited | Hospitality | 2017 |
| Systematic Logistics International Limited | Transport & logistics | 1994 |
| T & R Enterprises Limited | Administrative & support | 2003 |
| T & R Property Limited | Real estate | 2015 |
| T 2 Building Services Ltd. | Construction | 1999 |
| T a H Solutions Ltd | Information & communication | 2011 |
| T B Properties (Essex) Ltd | Real estate | 2025 |
| T Diamond & SON Roofing and Building Solutions Ltd | Construction | 2021 |
| T Gamby Holdings Ltd | Financial services | 2025 |
| T H Glazing Ltd | Construction | 2022 |