| Sparks Fitness Ltd | Arts & recreation | 2021 |
| Spectrum Security Installations Limited | Administrative & support | 2023 |
| Specurate Limited | Real estate | 1979 |
| Spicer Clarke Land Limited | Construction | 2024 |
| Spinnaker Health and Safety Consultants Ltd | Professional & scientific | 2019 |
| Spit & Polish Brand Design Ltd | Professional & scientific | 2023 |
| Spitalfields Interiors Ltd | Professional & scientific | 2024 |
| Splinter Galactic Limited | Administrative & support | 2014 |
| Spooky Purple Studios Ltd | Information & communication | 2025 |
| Sport 4 FUN Limited | Arts & recreation | 2011 |
| Sports Associated Solutions Limited | Arts & recreation | 2005 |
| Springbuks Group Services Limited | Construction | 2015 |
| SR Formulations Ltd | Manufacturing | 2025 |
| SR Motorworks Limited | Wholesale & retail | 2005 |
| SRK Martial Arts & Fitness LLP | | 2022 |
| SS Brow & Beauty Limited | Other services | 2025 |
| SS Cosmetics Limited | Other services | 2020 |
| SS12 Mastic Pointing Ltd | Construction | 2012 |
| SSM Car Valeting Ltd | Administrative & support | 2023 |
| SSP Auto Group Limited | Wholesale & retail | 2025 |
| ST BIM Solutions Ltd | Professional & scientific | 2024 |
| ST Cars Ltd | Transport & logistics | 2025 |
| ST James Services Limited | Information & communication | 1995 |
| ST Lawrence Caravans Group Ltd | Hospitality | 2024 |
| ST Mitchell Investments Ltd | Financial services | 2023 |
| ST Stephens Property Company Limited | Households | 2026 |
| ST Stephens Property Management Limited | Households | 2025 |
| ST. Georges Court (Shoeburyness) Limited | Households | 2002 |
| Staff Line Home Care Limited | Health & social care | 2002 |
| Stafford Financial LLP | | 2011 |
| Standout Exhibition Services Ltd | Administrative & support | 2021 |
| Stat Accounting Services Ltd | Professional & scientific | 2021 |
| Station Court Management (Wickford) Limited | Households | 1985 |
| Staunch Holdings Limited | Construction | 2024 |
| Stayabit Ltd | Real estate | 2021 |
| Stepflex Ltd | Professional & scientific | 2018 |
| Stephen Cornish Ltd | Manufacturing | 2023 |
| Stepney's Roofing Consultancy Services Limited | Construction | 2026 |
| Steve Mcdonald Crafts Limited | Information & communication | 2023 |
| Steve Wakeham Photography Limited | Professional & scientific | 2003 |
| Stevens Property Investments Limited | Real estate | 2024 |
| Still Here Clothing Limited | Wholesale & retail | 2025 |
| Stiltland Holdings Ltd | Financial services | 2025 |
| Stiltland Homes Limited | Construction | 2012 |
| Stiltland Properties Limited | Real estate | 2017 |
| Stiltland S Ltd | Manufacturing | 1994 |
| Stirling Lettings UK Ltd | Real estate | 2026 |
| Stirling Nova Finance Ltd | Financial services | 2025 |
| Stirum Limited | Professional & scientific | 2017 |
| STN Limited | Construction | 2018 |
| Stock Auto Breakers Limited | Wholesale & retail | 2014 |
| Stock Florist at Bishops Stortford Ltd | Wholesale & retail | 2020 |
| Stock Florist Ltd | Wholesale & retail | 2014 |
| Stock Media Limited | Administrative & support | 2013 |
| STONE4HOME Essex Limited | Wholesale & retail | 2024 |
| STONE4HOME Interiors Limited | Wholesale & retail | 2016 |
| Stonebeach Consulting Ltd | Professional & scientific | 2018 |
| Stoneford (U.K.) Limited | Construction | 2022 |
| Stoneford Services Limited | Administrative & support | 2023 |
| Storage Partition Solutions Limited | Construction | 2022 |
| Storms END Limited | Administrative & support | 2012 |
| STR8 R8 Limited | Professional & scientific | 2021 |
| Strata International UK Ltd | Real estate | 2019 |
| Stratech Solutions Ltd | Information & communication | 2019 |
| Strategium Consult Limited | Construction | 2019 |
| Stratford Manor Ltd | Real estate | 2020 |
| Stratford-Thorne Holdings Ltd | Real estate | 2016 |
| Stream Path Limited | Administrative & support | 2018 |
| Strive Strategies Limited | Professional & scientific | 2025 |
| STS Floor Screeds Limited | Construction | 2018 |
| Stuart Ikeman Hair Ltd | Other services | 2020 |
| Stuart Rucker Ltd | Manufacturing | 2008 |
| Stuart Taylor Aviation Ltd | Administrative & support | 2019 |
| Stubbs Freehold Properties Limited | Real estate | 2024 |
| Stubbs Properties Limited | Real estate | 2019 |
| Stubbs Site Services Limited | Construction | 2011 |
| Studio Mimic Ltd | Information & communication | 2024 |
| Studio Ultra Limited | Wholesale & retail | 2012 |
| Style Drywall Limited | Construction | 2024 |
| Style Living Interiors Limited | Construction | 2013 |
| Subsea and Offshore Solutions Limited | Construction | 2012 |
| Sun Goose Limited | Real estate | 2022 |
| Sun to Power Solar Ltd | Wholesale & retail | 2026 |
| Sunbury (Country Homes) LLP | | 2019 |
| Sunflower Homecare Ltd | Health & social care | 2019 |
| Sunland Tanning Ltd | Other services | 2022 |
| Sunland Tanning Wickford Ltd | Other services | 2026 |
| Sunor Ltd | Professional & scientific | 2015 |
| Sunrise Enterprises Limited | Real estate | 1996 |
| Sunshine Daze Media Group | Information & communication | 2021 |
| Sunshine Daze Studios Limited | Information & communication | 2025 |
| Sunshine Holidays Limited | Hospitality | 2019 |
| SUP Shop Ltd | Wholesale & retail | 2026 |
| Superior Solutions Ltd | Wholesale & retail | 2020 |
| Supreme Gleam Window Cleaning Ltd | Administrative & support | 2020 |
| Surface Masters Limited | Construction | 2012 |
| Sutton's Carpet & Furniture Centre Limited | Wholesale & retail | 1983 |
| Swabian Investment Group Ltd | Wholesale & retail | 2007 |
| Swami News Limited | Wholesale & retail | 2021 |
| Swan Acoustics Limited | Construction | 2005 |