| Sirhind Islamic Centre Ltd | Health & social care | 2012 |
| SJB Property & Maintenance Ltd | Real estate | 2022 |
| SJB Sash Windows Specialist Ltd | Construction | 2016 |
| SJC Movers Limited | Transport & logistics | 2025 |
| SJH Bookkeeping & Admin Support Ltd | Professional & scientific | 2019 |
| Skainex Limited | Information & communication | 2025 |
| Skewback Ltd | Construction | 2019 |
| SKI-3-UP Limited | Wholesale & retail | 2003 |
| Skin Vitality Ltd | Health & social care | 2024 |
| Skinvital Clinic Ltd | Health & social care | 2024 |
| Skinvive Clinic Ltd | Health & social care | 2025 |
| Skyrah Care Limited | Health & social care | 2022 |
| Skys the Limit Solutions Ltd | Construction | 2024 |
| Skyworkers Building Company Ltd | Construction | 2017 |
| SL Consultings Limited | Transport & logistics | 2022 |
| SL Props and Effects Ltd | Other services | 2008 |
| Slee Decorating Services Ltd | Construction | 2022 |
| Sleek Property Management Ltd | Real estate | 2023 |
| SLN Infotech Ltd | Information & communication | 2023 |
| Slnr Properties Ltd | Real estate | 2025 |
| Slomau Business Services Ltd | Professional & scientific | 2015 |
| SM GAS & Plumbing Solutions Ltd | Construction | 2018 |
| Smart Auto Retail Ltd | Wholesale & retail | 2019 |
| Smart Electrical AV Solutions Ltd | Construction | 2013 |
| Smart Structure Ltd | Professional & scientific | 2021 |
| Smart Webshop Limited | Information & communication | 2008 |
| SMS Capital Ltd | Real estate | 2023 |
| Snappysnug Limited | Education | 2026 |
| SNG Technology and Innovation Ltd | Information & communication | 2024 |
| Snowburst Limited | Information & communication | 2004 |
| Softgenie Ltd | Wholesale & retail | 2019 |
| Solaland Ltd | Wholesale & retail | 2020 |
| Solestrium Property Management Limited | Real estate | 2023 |
| Solidcore London Ltd | Construction | 2026 |
| Solok FM Services Ltd | Administrative & support | 2026 |
| Solutionify Ltd | Information & communication | 2022 |
| Some Earth Investments Ltd | Real estate | 2018 |
| Sounds Easy Limited | Administrative & support | 2026 |
| South London Shine Ltd | Administrative & support | 2025 |
| Sowqua Ventures Ltd | Transport & logistics | 2017 |
| SP Pereira Sales Ltd | Wholesale & retail | 2021 |
| Sparky & Wire Ltd | Construction | 2024 |
| Specialist Limited | Wholesale & retail | 2004 |
| Sperling Car Valeting & Detailing Ltd | Administrative & support | 2022 |
| Spi-Tek Electrical Services Limited | Construction | 2017 |
| Spilt Milk Food Bar Limited | Hospitality | 2019 |
| Sports Hive Limited | Arts & recreation | 2017 |
| Spotless Touch Limited | Administrative & support | 2023 |
| Springis Group Limited | Information & communication | 2022 |
| Spycn.S Ltd | Wholesale & retail | 2025 |
| SPZ Cleaning Ltd | Administrative & support | 2023 |
| Squareline Designs Ltd | Wholesale & retail | 2017 |
| SR Cabugon Limited | Health & social care | 2022 |
| SRI Care Home UK Ltd | Health & social care | 2025 |
| SRI Vaishnavai Services Limited | Information & communication | 2015 |
| Sriyaan Limited | Real estate | 2021 |
| SS Eyecare Ltd | Health & social care | 2021 |
| Sseg Investments Ltd | Professional & scientific | 2014 |
| Ssema Enterprise Ltd | Health & social care | 2019 |
| SSN Retailers UK Ltd | Wholesale & retail | 2023 |
| ST Helier Estates Limited | Real estate | 2015 |
| ST Saviours Property Ltd | Real estate | 2024 |
| ST. Anna | Health & social care | 2009 |
| ST. Philomena's Carshalton Charitable Trust | Education | 1995 |
| Staccato Ltd | Arts & recreation | 2008 |
| Stamford House Residents Limited | Households | 2010 |
| Stanchev Limited | Construction | 2018 |
| Stanley Kebabs Ltd | Hospitality | 2019 |
| Staplefields Consulting Ltd | Professional & scientific | 2026 |
| Star Human Design CIC | Education | 2025 |
| Star Hydrogen Limited | Energy | 2021 |
| Starmax Systems Limited | Mining & quarrying | 1999 |
| Steadfast Business Solution Limited | Information & communication | 2015 |
| STEFAN1 Ltd | Manufacturing | 2024 |
| Stemz Services Limited | Administrative & support | 2007 |
| Stephen Alfrey Ltd | Other services | 2015 |
| Stepney Psychological Medicine Ltd | Health & social care | 2023 |
| Sterling Exec Ltd | Transport & logistics | 2013 |
| Sterling Ice Limited | Households | 1999 |
| Stern Alarum Limited | Arts & recreation | 2013 |
| Stevefrancis Barbers UK Ltd | Other services | 2025 |
| Stjk Limited | Real estate | 2023 |
| Stone Leasehold Management Limited | Real estate | 2006 |
| Stone Properties & Management Ltd | Real estate | 2006 |
| Storage Goals Ltd | Wholesale & retail | 2017 |
| Storykiln by Planet Small Ltd | Information & communication | 2026 |
| Stovi Plumbing Ltd | Construction | 2014 |
| STR Design and Print Limited | Administrative & support | 2014 |
| Stratus Building and Mechanical Services Ltd | Construction | 2021 |
| Stronsaule Consultant Limited | Professional & scientific | 2020 |
| Studio Red Ltd | Professional & scientific | 2024 |
| Studio Saints Group Ltd | Financial services | 2025 |
| Studio Saints Ltd | Professional & scientific | 2025 |
| Stuey Ltd | Health & social care | 2026 |
| Style by Natalie Ltd | Other services | 2024 |
| Stylesbyhettis UK Ltd | Other services | 2025 |
| Styoung Roofing Ltd | Construction | 2025 |
| Subrealism Ltd | Wholesale & retail | 2024 |
| Suckling Ltd | Administrative & support | 2025 |
| SUE GUO Ltd | Health & social care | 2023 |