| Security Supplies (Chelmsford) Limited | Wholesale & retail | 2009 |
| Security Supplies Limited | Wholesale & retail | 2000 |
| Sehaj and Viraj Limited | Real estate | 2020 |
| Selams Investments Limited | Real estate | 2022 |
| Send IT and Save Ltd | Transport & logistics | 2025 |
| Senea Consult Limited | Professional & scientific | 2018 |
| SEO Thatworks Ltd | Information & communication | 2009 |
| Seren Green Ltd | Transport & logistics | 2024 |
| Serventa Ltd | Wholesale & retail | 2025 |
| Service Assist UK Limited | Administrative & support | 2020 |
| Sesai Consulting Limited | Professional & scientific | 2006 |
| Sethi Brothers Limited | Real estate | 2015 |
| Sevenoaks (THH) LLP | | 2013 |
| Shalbourne Technology Limited | Information & communication | 2019 |
| Shalka Limited | Health & social care | 2015 |
| Shamscare Ltd | Health & social care | 2022 |
| Shanglian Youce Cultural Technology Co., Ltd | Information & communication | 2025 |
| Shant Ltd | Health & social care | 2023 |
| Shapla Restaurant (GB) Ltd | Hospitality | 2014 |
| Shapla White Takeaway Ltd | Hospitality | 2025 |
| Shark IT Limited | Information & communication | 2009 |
| Sharma Smiles Ltd | Health & social care | 2014 |
| Sharps Court Management Company Limited | Households | 2006 |
| Shawton Energy Limited | Construction | 2016 |
| Shawton Energy Point Lane Ltd | Energy | 2020 |
| Shawton Energy SPV (Burnley) Limited | Energy | 2021 |
| Shawton Energy SPV (Dungc) Limited | Energy | 2022 |
| Shawton Energy SPV (I&N) Limited | Energy | 2021 |
| Shawton Energy SPV (Obgpha) Limited | Energy | 2022 |
| Shawton Energy SPV (SEL) Limited | Energy | 2021 |
| Shawton Energy SPV (VH) Limited | Energy | 2021 |
| Shawton Energy SPV Limited | Energy | 2021 |
| Shawton Energy SPV10 Limited | Energy | 2021 |
| Shawton Energy SPV2 Limited | Energy | 2022 |
| Shawton Energy SPV3 Limited | Energy | 2023 |
| Shawton Energy SPV4 Limited | Energy | 2023 |
| Shawton Energy SPV5 Limited | Energy | 2023 |
| Shawton Energy SPV6 Limited | Energy | 2023 |
| Shawton Energy SPV7 Limited | Energy | 2023 |
| Shawton Energy SPV8 Limited | Energy | 2022 |
| Shawton Energy SPV9 Limited | Energy | 2022 |
| Sheff's Ltd | Hospitality | 2019 |
| Sheridan's Estate Agents Limited | Real estate | 2008 |
| Sherif Latif Consulting Ltd | Health & social care | 2019 |
| Shiftcreate Limited | Information & communication | 2006 |
| Shimmer Stone Limited | Wholesale & retail | 2026 |
| Ship and Save Ltd | Transport & logistics | 2025 |
| Shivan Enterprises Ltd | Hospitality | 2014 |
| Shoker Investments Limited | Real estate | 2017 |
| Shoo 501 Limited | Professional & scientific | 2010 |
| Shop Go Limited | Wholesale & retail | 2017 |
| Sids Labour Worx Ltd | Construction | 2022 |
| Signature Zero Energy Systems Limited | Manufacturing | 2025 |
| Signs Delivered Ltd | Manufacturing | 2020 |
| Silistima Ltd | Professional & scientific | 2019 |
| Silka Ltd | Administrative & support | 2023 |
| Silletta Limited | Manufacturing | 2025 |
| Silva Cosmetics Limited | Other services | 2024 |
| Silva Wellness Limited | Other services | 2024 |
| Silveroak Investments Ltd | Real estate | 2018 |
| Silversmith Homes Limited | Real estate | 2020 |
| Simviraj Limited | Real estate | 2016 |
| Singing Cactus Ltd | Information & communication | 2020 |
| Sive Consulting Limited | Professional & scientific | 2026 |
| Sivyer Design Ltd | Professional & scientific | 2022 |
| SJC Plumbing & Heating Services Limited | Construction | 2019 |
| SJD Properties (Herts) Limited | Real estate | 2026 |
| Skylight Energy Ltd | Construction | 2023 |
| Sloane Curtis Solutions Ltd | Wholesale & retail | 2020 |
| SM Surveyors & Co Ltd | Professional & scientific | 2014 |
| SM Welding and Fabrication Ltd | Manufacturing | 2018 |
| Smart SAP Logistics Limited | Information & communication | 2017 |
| Smarter Thinking Ltd | Other services | 2021 |
| Smithfield Search Limited | Administrative & support | 2025 |
| Smiths Metal Centres Limited | Wholesale & retail | 1997 |
| Snap Cleaners Ltd | Administrative & support | 2023 |
| Solaris Contracts Ltd | Construction | 2021 |
| Solidarity Projects Ltd. | Education | 2013 |
| Sollershott Holdings Limited | Financial services | 2021 |
| Sollershott Limited | Professional & scientific | 2015 |
| Sollershott Lodge Management Company Limited | Households | 2002 |
| Soma Safety Solutions Limited | Energy | 2014 |
| Sonia Yvonne LEE Limited | Extraterritorial | 2022 |
| Sonia Yvonne Simpson Limited | Extraterritorial | 2022 |
| Sonolu Limited | Information & communication | 2020 |
| Sonovision Limited | Administrative & support | 1987 |
| Sooae Care Services Ltd | Health & social care | 2021 |
| Sorelle Sourcing Ltd | Real estate | 2019 |
| Soundgate Maintenance Limited | Real estate | 2020 |
| South Lodge Residents Management Company Limited | Households | 2002 |
| Southcott Racing Limited | Agriculture & fishing | 1964 |
| Southfield Fish & Chips Ltd | Hospitality | 2026 |
| Southfields Groceries Ltd | Manufacturing | 2025 |
| Southfields Superstore Ltd | Wholesale & retail | 2020 |
| Southview Sales Limited | Professional & scientific | 2012 |
| Sowhatnowwhat Ltd | Information & communication | 2026 |
| SP7 Logistics Ltd | Transport & logistics | 2025 |
| Space Babies Ltd | Education | 2023 |
| Special Needs Labyrinth Ltd | Education | 2025 |
| Specialist Aviation Holdings Limited | Financial services | 2009 |