| Source Info Ltd | Information & communication | 2023 |
| South Property Holdings Ltd | Real estate | 2025 |
| Southwestern Ltd | Wholesale & retail | 2025 |
| Spabjag Ltd | Education | 2022 |
| Space AS a Service Ltd | Real estate | 2025 |
| Space Aware Intelligence Ltd | Information & communication | 2024 |
| Space Nugget Ltd | Real estate | 2015 |
| Space Only Exhibitions Limited | Administrative & support | 2020 |
| Space Property Services Ltd | Real estate | 2025 |
| Space Travel (Otford) Limited | Transport & logistics | 2003 |
| Spacious Developments Ltd | Real estate | 2006 |
| Spalding Lithuanian CIC | Education | 2023 |
| Spangle Media Ltd | Information & communication | 2021 |
| Sparerooms Finder Ltd | Real estate | 2026 |
| Sparkle Property Development Ltd | Construction | 2025 |
| Sparkledun Limited | Financial services | 2017 |
| Sparkling Waste Services Ltd | Wholesale & retail | 2025 |
| Sparklweb Software Services Ltd | Information & communication | 2025 |
| Spatial Global Limited | Transport & logistics | 1977 |
| Speakers Corner Quartet Ltd | Arts & recreation | 2021 |
| Speaktheworld Adults Ltd | Education | 2024 |
| Spechaus Automotive Ltd | Wholesale & retail | 2026 |
| Special Circumstances Limited | Administrative & support | 2010 |
| Special People Partnership Limited | Health & social care | 2010 |
| Speedline Sourcing Limited | Information & communication | 2025 |
| Speedprint Essex Limited | Arts & recreation | 2002 |
| Spencer Services Limited | Professional & scientific | 2007 |
| Spenjay-El-Roy Limited | Public administration | 2025 |
| Spice of Chigwell Limited | Hospitality | 2019 |
| Spiddal Plant and Construction Co. Limited | Administrative & support | 1973 |
| Spindle Engineering Ltd | Other services | 2014 |
| Spine Plus Limited | Health & social care | 2003 |
| Spiral Property Design Company Limited(The) | Real estate | 1982 |
| Spiritual Lifestyle Ltd | Other services | 2023 |
| SPJ & Co Ltd | Information & communication | 2006 |
| Splash & Boats Ltd | Arts & recreation | 2020 |
| Spoc JC Ltd | Information & communication | 2025 |
| Sponsivity Limited | Information & communication | 2024 |
| Spread the Joy Ltd | Extraterritorial | 2018 |
| Spring Grove Ltd | Real estate | 2015 |
| Spring Properties (UK) Holdings Limited | Real estate | 2016 |
| Spring Properties LH (UK) Ltd | Real estate | 2018 |
| Springbridge Properties Ltd | Real estate | 2024 |
| Spur Road Facility Limited | Arts & recreation | 2010 |
| Spyrou Motors Limited | Wholesale & retail | 2016 |
| SQ Clothing Ltd | Wholesale & retail | 2021 |
| SQ Studios Ltd | Other services | 2022 |
| SQL Horizons Limited | Administrative & support | 2014 |
| Squirrel Consulting Limited | Other services | 2023 |
| SR Constructions U.K. Limited | Construction | 2021 |
| Sreehari Medical Limited | Health & social care | 2025 |
| SRI Estates PVT Ltd | Real estate | 2023 |
| SRI Guru Ravidass International Organization for Human Rights | Health & social care | 2002 |
| Srijee Limited | Hospitality | 2023 |
| SS Estates London Ltd | Households | 2026 |
| SS Training Pros Limited | Arts & recreation | 2016 |
| SSA Ventures Ltd | Wholesale & retail | 2025 |
| ST Andrews Autos Limited | Wholesale & retail | 2022 |
| ST Clair Chanter Property Management Limited | Real estate | 2020 |
| ST James Windows London Ltd | Construction | 2019 |
| ST Olave's Place Ltd | Real estate | 2024 |
| ST. Albans Realty Limited | Real estate | 1981 |
| ST. Aubyn's (Woodford Green) School Trust | Education | 1975 |
| ST. James's House Group Limited | Information & communication | 2017 |
| Stable Close Management Company Limited | Households | 2004 |
| Stable Storage Property Ltd | Real estate | 2014 |
| Stagecraft Studios LLP | | 2023 |
| Stairway Projects Limited | Construction | 2003 |
| Stanbreck Properties Ltd | Real estate | 2001 |
| Standsure Ltd | Wholesale & retail | 2025 |
| Stanford Quarrie Art of Combat Limited | Arts & recreation | 2010 |
| Stanmore Point Limited | Real estate | 2023 |
| Stapleford Flying Club Limited | Other services | 1969 |
| Star Art Design Limited | Financial services | 2017 |
| Star Facilities Management Ltd | Administrative & support | 2025 |
| Star Pizza Ltd | Hospitality | 2019 |
| Star Pro Ltd | Wholesale & retail | 2023 |
| Star Reach Multimedia Limited | Administrative & support | 2012 |
| Star Season Hire Ltd | Transport & logistics | 2019 |
| Star Vyas Properties Ltd | Real estate | 2019 |
| Starfish Development Limited | Real estate | 2026 |
| Starguard Contracts Limited | Administrative & support | 1999 |
| Stark James Ltd | Administrative & support | 2016 |
| Starrocker Studios Ltd | Arts & recreation | 2020 |
| Startin Financial Services Limited | Financial services | 2024 |
| Static Light Company Limited | Manufacturing | 2000 |
| Station News Limited | Wholesale & retail | 2008 |
| Statliteco Ltd | Manufacturing | 2019 |
| Stefanoff Limited | Construction | 2014 |
| Stellar Logistics Ltd. | Transport & logistics | 2019 |
| Steph's Beauty Salon Ltd | Wholesale & retail | 2015 |
| Stephanie's Interiors Limited | Construction | 2005 |
| Sterling Printing Company Limited | Wholesale & retail | 1959 |
| Sterling Property Solutions Ltd | Real estate | 2012 |
| Steves Stairs Ltd | Manufacturing | 2021 |
| Stirling Autocare Limited | Wholesale & retail | 2015 |
| Stoa Global Ltd | Real estate | 2023 |
| Stockify Ltd | Wholesale & retail | 2019 |
| Stone Experts Ltd | Administrative & support | 2010 |
| Stone&Stich Ltd | Wholesale & retail | 2026 |