| S.G.S. Limited | Manufacturing | 1994 |
| S.H. Drylining Limited | Construction | 2015 |
| S.H.A.R.P. Commercial Limited | Real estate | 2005 |
| S.J.C. Drylining Ltd | Construction | 2014 |
| S.K.W DRY Ice Blasting Ltd | Administrative & support | 2025 |
| S.M Home Improvements (London) Ltd | Construction | 2017 |
| S.M.F. Services Ltd | Construction | 1997 |
| S.P. Carpentry & Joinery Ltd | Construction | 2015 |
| S.P.E.D Electrical Limited | Construction | 2021 |
| S.R.G. Properties Limited | Real estate | 1975 |
| S.Rogers.Properties Ltd | Real estate | 2025 |
| S.T. Glazing Limited | Construction | 1995 |
| S10 Limited | Construction | 2010 |
| S10 Manufacturing Limited | Manufacturing | 2022 |
| S8 Services Ltd | Administrative & support | 2026 |
| SA Maintenance Limited | Construction | 2014 |
| SA4HIRE Drivers Ltd | Administrative & support | 2021 |
| Saanya Reporting Limited | Health & social care | 2019 |
| Saas Studios Ltd | Information & communication | 2025 |
| SAB Construction Ltd | Construction | 2018 |
| Sab&T (UK) Limited | Professional & scientific | 2006 |
| Sabaton Services Ltd | Real estate | 2023 |
| Sabi Seeds Ltd | Wholesale & retail | 2021 |
| Sabmar Ltd | Information & communication | 2019 |
| Saddles by ZOE Ltd | Wholesale & retail | 2022 |
| Safe Haven and Respite Enviroment | Health & social care | 2013 |
| Safe Mate Limited | Construction | 2026 |
| Safe Pass Limited | Manufacturing | 2008 |
| Safe Shield Security Ltd | Administrative & support | 2023 |
| SAFE2SAY Counselling Ltd | Health & social care | 2019 |
| Safeplumb Limited | Professional & scientific | 2007 |
| Saferock Alternative Energy Ltd | Extraterritorial | 2024 |
| Saferock Aquaculture Ltd | Agriculture & fishing | 2024 |
| Saferock Environmental Ltd | Extraterritorial | 2024 |
| Saferock Feed Ltd | Mining & quarrying | 2024 |
| Saferock Global Ltd | Mining & quarrying | 2026 |
| Saferock Health Ltd | Other services | 2024 |
| Saferock Holdings Ltd | Financial services | 2023 |
| Saferock International Limited | Mining & quarrying | 2024 |
| Saferock Limited | Manufacturing | 2013 |
| Saferock Logistics Limited | Extraterritorial | 2023 |
| Saferock Minerals Limited | Mining & quarrying | 2024 |
| Saferock Research and Development Ltd | Professional & scientific | 2024 |
| Saferock Seed Capital Ltd | Mining & quarrying | 2024 |
| Safespace Care Homes Ltd | Health & social care | 2025 |
| Safety Netting Essex Ltd | Construction | 2025 |
| Safetyneeds Limited | Health & social care | 2015 |
| Safwan Kabeer Ltd | Health & social care | 2023 |
| Saga Logistics Ltd | Transport & logistics | 2019 |
| Sagacity Network Ltd | Information & communication | 2024 |
| Sagoch Limited | Wholesale & retail | 2011 |
| SAH Logistics Ltd | Construction | 2023 |
| SAI Optometry Ltd | Health & social care | 2017 |
| Saiaum Limited | Other services | 2019 |
| Saicloud Technologies Ltd | Information & communication | 2026 |
| Saida-Q Limited | Construction | 2025 |
| Sainsation Limited | Construction | 2024 |
| Saint Safety Ltd | Administrative & support | 2019 |
| Saint Spaces Limited | Real estate | 2022 |
| Sait Ltd | Professional & scientific | 2018 |
| Salak Ltd | Wholesale & retail | 2025 |
| Salamander 3D Limited | Professional & scientific | 2007 |
| Sale Education Development Ltd | Administrative & support | 2023 |
| Salescape Limited | Wholesale & retail | 2021 |
| Salix Kitchens and Bars Limited | Manufacturing | 2020 |
| Salix Stainless Steel Fabrications Limited | Manufacturing | 1992 |
| Salon MAE Ltd | Other services | 2024 |
| Salon Sisters (Billericay) Limited | Other services | 2026 |
| Salon T Limited | Other services | 2015 |
| Salt & Glow Ltd | Health & social care | 2025 |
| Salter Networks Limited | Construction | 2025 |
| Saltmarsh Automotive Ltd | Wholesale & retail | 2023 |
| Salvage Malayali Ltd | Wholesale & retail | 2025 |
| Salvation Chapel International | Other services | 2011 |
| SAM Construct & Development Ltd | Construction | 2026 |
| SAM Consulting Services Ltd | Professional & scientific | 2026 |
| SAM FBA Ltd | Extraterritorial | 2024 |
| SAM Heavey Plumbing & Heating Limited | Construction | 2022 |
| SAM Traders (GB) Ltd | Wholesale & retail | 2014 |
| Sam's Kitchen Vange Ltd | Hospitality | 2025 |
| Samad Cars Ltd | Wholesale & retail | 2024 |
| Samade Cleaning Services Ltd | Administrative & support | 2025 |
| Samas Cleaning Ltd | Administrative & support | 2024 |
| Sameralya Ltd | Health & social care | 2021 |
| Samidav Solutions Ltd | Construction | 2026 |
| Sammay Consultants Limited | Health & social care | 2010 |
| Samog Ltd | Information & communication | 2022 |
| Samog Virtual Ltd | Wholesale & retail | 2024 |
| Sams Group Ltd | Health & social care | 2012 |
| Sams Portering Services Limited | Transport & logistics | 2022 |
| Samuel Perry Jewellery Limited | Wholesale & retail | 2022 |
| Samuelston Limited | Manufacturing | 2006 |
| Sanberto Trans Limited | Transport & logistics | 2019 |
| Sandhu Property Group Limited | Real estate | 2019 |
| Sandown Media Ltd | Information & communication | 2025 |
| Sandrini Limited | Administrative & support | 2003 |
| Saneshoppe Ltd | Wholesale & retail | 2015 |
| Sankot Properties Limited | Real estate | 2024 |
| Santa Maria Tattoo Limited | Other services | 2020 |
| Santoramo Ltd | Information & communication | 2017 |