| Squire Editions Ltd | Manufacturing | 2019 |
| Srdw Ltd | Construction | 2026 |
| SRK Print Solutions Ltd | Manufacturing | 2024 |
| SS Diagnostic Engineering Limited | Professional & scientific | 2018 |
| SSJ Electrical U.K. Limited | Construction | 2016 |
| ST Civil Services Limited | Construction | 2014 |
| ST Close Limited | Construction | 2020 |
| ST Georges Solutions Limited | Extraterritorial | 2010 |
| ST James Courier Limited | Transport & logistics | 2019 |
| ST John's School | Education | 2005 |
| ST Rambert Consulting Limited | Professional & scientific | 2011 |
| ST Valery Investments Limited | Construction | 2007 |
| ST. John Carpentry Limited | Construction | 2010 |
| Stable Self-Storage Limited | Real estate | 2008 |
| Stableforce Limited | Construction | 1984 |
| Stammerun Limited | Manufacturing | 2024 |
| Stanbrook Ltd | Professional & scientific | 2022 |
| Stanley Rise (Chelmsford) RTM Company Limited | Households | 2018 |
| Stanton Hockett Lettings Ltd | Real estate | 2022 |
| Stanton Hockett Limited | Real estate | 2021 |
| Stanwell Holdings Ltd | Financial services | 2025 |
| Stanwell Property Group Ltd | Real estate | 2022 |
| Stapleton Building Services Limited | Construction | 2012 |
| Star (Essex) Limited | Wholesale & retail | 2015 |
| Star Consultants Group Ltd | Professional & scientific | 2019 |
| Star Finance Group Limited | Extraterritorial | 2023 |
| Star Sourcing Limited | Manufacturing | 2011 |
| Startsafe Technologies Limited | Information & communication | 2019 |
| Statrack Limited | Information & communication | 2023 |
| Stay & Play (Basildon) Limited | Arts & recreation | 2012 |
| Steadi Lifestyle Ltd | Education | 2023 |
| Stecla Limited | Construction | 2013 |
| Stede Limited | Real estate | 2025 |
| Steelwoodgroup Ltd | Financial services | 2024 |
| Stem Property Services Limited | Construction | 2023 |
| Step in 19 Ltd | Wholesale & retail | 2019 |
| Step in 2 Sport Ltd | Education | 2025 |
| Stephen Caraccio Photography Limited | Professional & scientific | 2022 |
| Sterling Protection Ltd | Administrative & support | 2022 |
| Sterling Street Foundation | Other services | 2025 |
| Sterling Street Limited | Financial services | 2020 |
| Steve Clark Advisory Services Ltd | Information & communication | 2010 |
| Steve LEE Studios Limited | Professional & scientific | 2011 |
| Stevemj Limited | Financial services | 2013 |
| Steven Building Services Ltd | Construction | 2009 |
| Steven Edward Armstrong Case Management Ltd | Health & social care | 2026 |
| Stevens Contracts Limited | Construction | 2018 |
| Stewart Enterprise Solutions Ltd | Information & communication | 2025 |
| Stewart Group Ltd | Financial services | 2023 |
| Stock Village Joinery Ltd | Manufacturing | 2022 |
| Stone and Spear Ltd | Professional & scientific | 2020 |
| Stoner Estates Ltd | Construction | 2023 |
| Stonewake Property Ltd | Real estate | 2026 |
| Stoneyhills Management Company Limited | Households | 2020 |
| Stow Wealth Management Limited | Professional & scientific | 2010 |
| Stows Hill Close Ltd | Real estate | 2025 |
| Straightline Construction Services Limited | Construction | 2005 |
| Strait Logics Limited | Administrative & support | 1997 |
| STRATIFY7 Limited | Professional & scientific | 2025 |
| Stratton Opticians Limited | Health & social care | 2015 |
| Stratus Data Developments Limited | Information & communication | 2024 |
| Strongco Ltd | Construction | 2020 |
| STU Barnes Limited | Transport & logistics | 2019 |
| Stuart O'Neill Specialist Services Ltd | Professional & scientific | 2014 |
| Studio 360 Fitness Ltd | Arts & recreation | 2011 |
| Studio Ferns Ltd | Wholesale & retail | 2026 |
| Studio Spruce Limited | Manufacturing | 2024 |
| Stunt Rigging Worldwide Limited | Information & communication | 2017 |
| Sturgess Speech Therapy Ltd | Health & social care | 2012 |
| Stylacity Ltd | Wholesale & retail | 2019 |
| Subterfuge.London Ltd | Administrative & support | 2025 |
| Sugarloaf RDA | Health & social care | 2013 |
| Sullivan White Limited | Construction | 2019 |
| Summerhill Nurseries Limited | Wholesale & retail | 1980 |
| Sunnex Properties Ltd | Real estate | 2019 |
| Sunny Motorhome Hire Limited | Administrative & support | 2018 |
| Sunripe Pacific Limited | Transport & logistics | 2023 |
| Sunrise Red Limited | Real estate | 2024 |
| Suoni Music Management Ltd | Arts & recreation | 2013 |
| Superfix Partitions & Ceilings Limited | Construction | 2020 |
| Superguttervac Limited | Other services | 2022 |
| Superior Coaches Ltd | Transport & logistics | 2007 |
| Superior Lighting Limited | Wholesale & retail | 2011 |
| Superior Total Solutions Limited | Transport & logistics | 2022 |
| Superiordatagroup Ltd | Information & communication | 2019 |
| Supersets Scenery Ltd | Construction | 2025 |
| Surego Administrative Services (UK) Ltd | Financial services | 2025 |
| Surego Assist Ltd | Financial services | 2026 |
| Surface Repair Pros Ltd | Construction | 2021 |
| Surig Consultants & Developments Ltd | Professional & scientific | 2013 |
| Surrey Landscapes and Garden Designs Ltd | Administrative & support | 2022 |
| Surveysure Limited | Professional & scientific | 2026 |
| Susanne Deeken Limited | Professional & scientific | 2007 |
| Sustainable Leaders Limited | Professional & scientific | 2022 |
| SVM 1 Management Limited | Administrative & support | 2012 |
| SVM 1 Property Management Limited | Real estate | 2017 |
| Swallows Cross Developments Limited | Construction | 2003 |
| Swami Samarth Ltd | Health & social care | 2018 |
| Swandale Limited | Professional & scientific | 2009 |
| SWB (Wickford) Limited | Real estate | 2018 |