| SL Handyman Ltd | Construction | 2015 |
| SL Khandaker Ltd | Transport & logistics | 2019 |
| SLAB4SLAB Ltd | Wholesale & retail | 2025 |
| Slavena Ltd | Wholesale & retail | 2018 |
| Slights Building Company Ltd | Construction | 2013 |
| SLN SAP Consulting Ltd | Information & communication | 2017 |
| Slotright Property Management Limited | Real estate | 1990 |
| Slow Vision Ltd | Professional & scientific | 2023 |
| SLS Buildings (PVT) Ltd | Real estate | 2025 |
| SLS Stores Limited | Wholesale & retail | 2025 |
| Slumbertots Sleep Consultancy Limited | Health & social care | 2016 |
| SLV Info Systems Ltd | Information & communication | 2011 |
| SM Accountax Limited | Professional & scientific | 2016 |
| SM One Two Ltd | Transport & logistics | 2022 |
| SM Square Limited | Real estate | 2023 |
| SM Timber Works Limited | Manufacturing | 2025 |
| SM1 Cleaning Limited | Administrative & support | 2025 |
| SM1 Events Ltd | Information & communication | 2017 |
| SM1 Management Ltd | Construction | 2020 |
| SM1 Properties Ltd | Real estate | 2025 |
| SM8 Consulting Limited | Information & communication | 2010 |
| Smadha Ltd | Professional & scientific | 2025 |
| Smart AV & Security Group Ltd | Information & communication | 2023 |
| Smart Build Homes Wembley Limited | Real estate | 2023 |
| Smart Gardens & Cleaning Ltd | Administrative & support | 2021 |
| Smart Music Studios Ltd | Education | 2026 |
| Smart Pictures Ltd | Wholesale & retail | 2019 |
| Smart Repair GUY Ltd | Wholesale & retail | 2022 |
| Smart Spark Solutions Ltd | Construction | 2025 |
| Smart Study Academy Ltd | Education | 2025 |
| Smart Study Learning CIC | Education | 2025 |
| Smart Tax Advisers Ltd | Professional & scientific | 2024 |
| Smart Taxes Limited | Professional & scientific | 2019 |
| Smart Termo Limited | Construction | 2025 |
| Smart Urban Stays Ltd | Real estate | 2026 |
| Smartdev Solutions Ltd | Information & communication | 2024 |
| Smarter Metering Services Limited | Manufacturing | 2012 |
| Smarteye Productions Limited | Information & communication | 2012 |
| Smartica Group Ltd | Other services | 2016 |
| Smartview Services Limited | Information & communication | 2017 |
| Smawora Ltd | Wholesale & retail | 2025 |
| SMC Heating Ltd | Construction | 2025 |
| SMC Roofing Ltd | Construction | 2019 |
| SME Business Finance Limited | Financial services | 2012 |
| Smes Business Advisory Ltd | Other services | 2023 |
| SMI 77 Limited | Construction | 2020 |
| Smiles on Wheels Ltd | Health & social care | 2024 |
| Smith & Co Construction Limited | Construction | 2018 |
| Smith and Byford Limited | Construction | 1972 |
| Smith Carpets Limited | Wholesale & retail | 2021 |
| Smith Wright Electrical Services LLP | | 2022 |
| Smooth Speed Ltd | Information & communication | 2024 |
| Smoozly Creative Ltd | Arts & recreation | 2022 |
| SMS (Surrey) Limited | Construction | 2022 |
| SMS Electrical Services (London) Ltd | Construction | 2018 |
| SMS Foods and Caterer Ltd | Hospitality | 2022 |
| SMS Global Facilities Ltd | Health & social care | 2025 |
| Smugmug Limited | Administrative & support | 2011 |
| Smyth Creations Limited | Arts & recreation | 2015 |
| SNA Ventures Limited | Information & communication | 2020 |
| Snackcorner Ltd | Wholesale & retail | 2026 |
| Snail Estates Limited | Real estate | 2019 |
| Snapcases Ltd | Wholesale & retail | 2025 |
| Snapdeal Trade Ltd | Wholesale & retail | 2023 |
| SNH Properties Ltd | Real estate | 2011 |
| SNJ Health Limited | Wholesale & retail | 2023 |
| SNQ Super Store Ltd | Wholesale & retail | 2026 |
| Snugtoes Limited | Wholesale & retail | 2015 |
| SO Go Solar Ltd | Construction | 2010 |
| SO Pickleball UK Ltd | Wholesale & retail | 2024 |
| SO Stay at Home Ltd | Wholesale & retail | 2020 |
| Sobremesa Serene Living Ltd | Wholesale & retail | 2025 |
| Social Buzzing Limited | Information & communication | 2015 |
| Social Living Property Limited | Real estate | 2021 |
| Sociological Review Foundation Limited | Education | 2014 |
| Sociological Review Publication Limited | Information & communication | 2014 |
| Sofra Triplets Ltd | Hospitality | 2026 |
| Softlight Electrical Limited | Administrative & support | 2006 |
| Soho Commercial Limited | Wholesale & retail | 2008 |
| Soho Consulting Limited | Manufacturing | 2002 |
| Sohun Limited | Health & social care | 2013 |
| SOJ Property Holdings Ltd | Real estate | 2023 |
| SOL Healing Limited | Administrative & support | 2012 |
| SOL4R Energy Ltd | Construction | 2022 |
| Solace Games Limited | Arts & recreation | 2024 |
| Solankinvest Limited | Real estate | 2021 |
| Solar Energy Pioneers Limited | Energy | 2017 |
| Solar Radiant UK Ltd | Construction | 2022 |
| Solaris Energy Solutions Ltd | Information & communication | 2023 |
| Solarsmith Ltd | Extraterritorial | 2023 |
| Solartech Energy Consultancy Ltd | Professional & scientific | 2024 |
| Soldier Studio Ltd | Arts & recreation | 2023 |
| Solid General Works Ltd | Construction | 2017 |
| Solidliving Ltd | Health & social care | 2025 |
| Solivra Immigration Limited | Professional & scientific | 2026 |
| Solomon Computing Ltd | Information & communication | 2025 |
| Solomon Solutions Ltd | Construction | 2020 |
| Soluda Limited | Real estate | 2020 |
| Solve Education Consultancy Ltd | Education | 2016 |
| Solverpoint Consulting Ltd | Information & communication | 2024 |