| Simadyl Properties LLP | | 2015 |
| Simba Home 4 Ever Ltd | Real estate | 2024 |
| Simmi Imports Ltd | Wholesale & retail | 2023 |
| Simon Roofing & Co Limited | Construction | 2021 |
| Simple Touch Decor Limited | Hospitality | 2024 |
| Simran Investments Inc. Ltd | Professional & scientific | 2018 |
| Sinclair Renovations Limited | Construction | 2026 |
| Sinclair Restorations Ltd | Construction | 2025 |
| Singh & Kaur Services PVT Ltd | Hospitality | 2020 |
| Sionara Limited | Information & communication | 2011 |
| Siril Property Management Limited | Real estate | 2020 |
| Siteland Limited | Real estate | 2023 |
| Sitelock Ltd | Real estate | 2022 |
| SIX Seasons Property Ltd | Real estate | 2020 |
| Sixthirty.X Trading Limited | Wholesale & retail | 2024 |
| Sixty SIX Pictures Limited | Information & communication | 2008 |
| SK 91 Limited | Real estate | 2022 |
| SK Canvas Limited | Professional & scientific | 2025 |
| SK9 Secuirty Services Ltd | Administrative & support | 2026 |
| Sketchline Pilates Ltd | Arts & recreation | 2025 |
| Skhc Ltd | Real estate | 2026 |
| Skin Elements Clinics Limited | Other services | 2024 |
| Skin Sculpt Clinic Ltd | Health & social care | 2020 |
| SKM Management Ltd | Real estate | 2024 |
| SKS Accountants Limited | Professional & scientific | 2019 |
| SKV Properties Limited | Real estate | 2017 |
| Sky Silk Road Limited | Transport & logistics | 2019 |
| Skyline Prop Limited | Construction | 2024 |
| Skylinecommerce Ltd | Wholesale & retail | 2024 |
| Slamd Ltd | Health & social care | 2023 |
| Slatna Ltd | Construction | 2016 |
| SMA Homes Ltd | Real estate | 2025 |
| Smart Care Homes Group Limited | Health & social care | 2021 |
| Smart Care Homes Limited | Health & social care | 2009 |
| Smart Recruitment Services Ltd | Construction | 2018 |
| Smart Rock Consult Limited | Other services | 2019 |
| SMK Property Holdings Limited | Households | 2022 |
| Smrv Enterprises Limited | Hospitality | 2025 |
| Smuj Ltd | Wholesale & retail | 2025 |
| SN Trans Rapid Ltd | Transport & logistics | 2023 |
| Snackhouse Supply Ltd | Wholesale & retail | 2026 |
| Snowman Limited | Administrative & support | 1997 |
| Snowwell Limited | Real estate | 2001 |
| Snugs-Baby Limited | Wholesale & retail | 2020 |
| SO Hotels Management Limited | Administrative & support | 2015 |
| SO Management Services (UK) Limited | Real estate | 2014 |
| Sochblooms Limited | Wholesale & retail | 2025 |
| Solmedic Ltd | Health & social care | 2025 |
| Solva Recruitment Limited | Administrative & support | 2024 |
| Sonsports Ltd | Real estate | 2018 |
| Soollo Properties Limited | Real estate | 2023 |
| Soreo Limited | Professional & scientific | 2014 |
| Sorrido Limited | Wholesale & retail | 2020 |
| Sotrans Ltd | Transport & logistics | 2015 |
| Soul Construction Ltd | Construction | 2017 |
| Southern ROW Investments Limited | Real estate | 2022 |
| Southwood Consulting Ltd | Administrative & support | 2018 |
| SP Property Estates Management Limited | Real estate | 2023 |
| Space Vista Limited | Wholesale & retail | 2005 |
| Sparrow Corporation Limited | Wholesale & retail | 2013 |
| Spartans Recycling Group Ltd | Wholesale & retail | 2026 |
| Spartans Services Ltd | Construction | 2015 |
| SPM Bar & Restaurant Ltd | Hospitality | 2025 |
| Spray Innovations Ltd | Construction | 2024 |
| Spray's Property Ltd | Manufacturing | 1972 |
| Spray’S Bakeries Limited | Manufacturing | 2012 |
| Sprd LDN Limited | Hospitality | 2026 |
| SQC Superior Quality Construction Ltd | Construction | 2023 |
| Square Box View Limited | Manufacturing | 2023 |
| SRD Business Services Limited | Real estate | 2010 |
| SS LDN Limited | Professional & scientific | 2024 |
| SS Strategy & Consulting Ltd | Professional & scientific | 2026 |
| ST Clements Walk Block L Management Company Limited | Households | 1990 |
| ST Clements Walk Block N Management Company Limited | Households | 1990 |
| ST Clements Walk Block R Management Company Limited | Households | 1990 |
| ST Patrick's Place Limited | Administrative & support | 2015 |
| ST. Pancras Hospitality Limited | Real estate | 2021 |
| Star Construction (Essex) Limited | Construction | 2026 |
| Starmarket Ltd | Other services | 2013 |
| Stars Move Ltd | Transport & logistics | 2026 |
| Station Road House Limited | Real estate | 2025 |
| Steelman Ltd | Construction | 2023 |
| Step Construction Ltd | Construction | 2017 |
| Stephen W Rose Company Limited | Real estate | 2021 |
| Stepping Stones Centre | Other services | 2011 |
| Sterling Harper Ltd | Wholesale & retail | 2024 |
| Sterling Prop Ltd | Wholesale & retail | 2025 |
| Still I Rise Events Ltd | Administrative & support | 2026 |
| Stilton Shop Limited | Wholesale & retail | 2024 |
| Stirling Reed Limited | Real estate | 2020 |
| Stirling Reed Wealth Management Limited | Professional & scientific | 2022 |
| Stonegate Renewable Infrastructure Ltd | Construction | 2025 |
| Stonekey Property Limited | Real estate | 2025 |
| Stonepage Limited | Extraterritorial | 1997 |
| Stones Galaxy Ltd | Manufacturing | 2025 |
| Stradbroke Park Management Company Limited | Households | 1986 |
| Strader Interactive Solution Limited | Administrative & support | 2007 |
| Stratix Media Ltd | Professional & scientific | 2025 |
| Strong Construct Ltd | Construction | 2021 |
| Studio at 308 Ltd | Arts & recreation | 2026 |