| Sonny Stores Ltd | Hospitality | 2025 |
| Sophie Rose Fitness Ltd | Arts & recreation | 2024 |
| Sopkem Limited | Professional & scientific | 2016 |
| Sorbet Dreams Ltd. | Wholesale & retail | 2018 |
| Sorbie Consultancy and Property Management Ltd | Information & communication | 2018 |
| Sound Healing UK Ltd | Wholesale & retail | 2024 |
| South Mill Services Ltd | Professional & scientific | 2023 |
| Southcote Ltd | Real estate | 2022 |
| Southern Helicopters Limited | Manufacturing | 1994 |
| Southern Livestock Exports Limited | Households | 1983 |
| Southern Lodge Management Company Limited | Households | 1988 |
| Southsea Studio Limited | Information & communication | 2022 |
| Sova Catering Ltd | Wholesale & retail | 2025 |
| Sovereign Court (Harlow) Limited | Households | 1986 |
| Sparkly Shine Ltd | Administrative & support | 2025 |
| Sparks Web Studio Ltd | Wholesale & retail | 2013 |
| SPC Project Services Limited | Extraterritorial | 2009 |
| SPD Law LLP | | 2019 |
| Spec Built Ltd | Construction | 2021 |
| Speed Couriers Nationwide Ltd | Transport & logistics | 2008 |
| Spellbrook Car Wash Ltd | Other services | 2018 |
| Spellbrook Electrical Ltd | Construction | 2022 |
| Spellbrook Hand Carwash Ltd | Administrative & support | 2026 |
| Spellbrook Systems Ltd | Professional & scientific | 2026 |
| Spellbrook Valeting Carwash Ltd | Other services | 2024 |
| Spellman Agriculture Limited | Financial services | 2026 |
| Spencer Plunkett Ltd | Professional & scientific | 2018 |
| Spero Consultancy Services International Ltd | Health & social care | 2015 |
| Spey Point Technology Limited | Information & communication | 2009 |
| Spice & Masala Ltd | Hospitality | 2022 |
| Spingrip Ltd | Wholesale & retail | 2025 |
| Splash & Glide Ltd | Education | 2026 |
| Sports Podiatry Info Ltd | Health & social care | 2010 |
| Spotlessly Klean Ltd | Administrative & support | 2024 |
| Spring Generation Limited | Professional & scientific | 2026 |
| Springfield Residents Association (Bishops Stortford) Limited | Households | 1973 |
| Springhall Mews Management Company Limited | Administrative & support | 1997 |
| Squibb Construction Limited | Construction | 2007 |
| SR Global Systems Ltd | Information & communication | 2017 |
| SRE Carpentry and Construction Limited | Construction | 2025 |
| SRF Construction Limited | Construction | 2017 |
| SRH Services Ltd | Construction | 2019 |
| Srini Kamal Ltd | Wholesale & retail | 2020 |
| SRS Real Estates Limited | Real estate | 2020 |
| SRS Wine Limited | Wholesale & retail | 2016 |
| SRT Services Ltd | Professional & scientific | 2019 |
| SS Sealants Ltd | Construction | 2025 |
| Ssrs Consultancy Ltd | Administrative & support | 2026 |
| ST Andrew's Park (NO. 1) Management Limited | Households | 1995 |
| ST Francis of Assisi Catholic Academy Trust | Education | 2021 |
| ST George European Trading Limited | Wholesale & retail | 2005 |
| ST John Patrick Media Limited | Professional & scientific | 2009 |
| ST1LLL Properties Limited | Households | 2025 |
| Stablegate Financial Services Ltd | Financial services | 2017 |
| Stacy Lord Ltd | Professional & scientific | 2018 |
| Staff 4HIRE Solutions Ltd | Administrative & support | 2023 |
| Staff Today Ltd | Administrative & support | 2026 |
| Stafford Young Jones LLP | | 2012 |
| Stance Fitness Ltd | Health & social care | 2020 |
| Stanford Eatwell Architecture Limited | Professional & scientific | 2014 |
| Stansted Aerospace Holdings Limited | Manufacturing | 2020 |
| Stansted Aerospace Limited | Manufacturing | 2004 |
| Stansted Airport Lodge Limited | Hospitality | 2017 |
| Stansted Airport Watch Foundation C.I.C. | Professional & scientific | 2024 |
| Stansted Car Club Ltd | Wholesale & retail | 2025 |
| Stansted Dervish Lodge Ltd | Hospitality | 2026 |
| Stansted Haulage Ltd | Transport & logistics | 2024 |
| Stanwell Stansted Limited | Hospitality | 2020 |
| Staple TYE Management Limited | Real estate | 1991 |
| Star Gate House Ltd | Hospitality | 2025 |
| Star Talent Solutions Limited | Administrative & support | 2021 |
| Starctec Ltd | Professional & scientific | 2019 |
| Stardust Collective Ltd | Information & communication | 2020 |
| Start Hill Limited | Construction | 2017 |
| Station Garage (Bishops Stortford) Limited | Wholesale & retail | 2025 |
| Stave Meadows Residents Management Company Limited | Households | 2020 |
| Stay at the Stables Ltd | Hospitality | 2024 |
| STAY@121STUDIO Ltd | Hospitality | 2021 |
| STE Dalton Ltd | Information & communication | 2020 |
| Stefano Rognoni Consulting Ltd | Professional & scientific | 2012 |
| Stehle UK Limited | Wholesale & retail | 1991 |
| Stelco International Limited | Wholesale & retail | 2009 |
| Stephanie Patterson Limited | Health & social care | 2024 |
| Stephen Keeley Associates Ltd | Professional & scientific | 2018 |
| Sterling & Co Estates Limited | Real estate | 2005 |
| Steve Bromley User Research Ltd | Professional & scientific | 2021 |
| Stewart Apau Limited | Professional & scientific | 2021 |
| Stews Limited | Hospitality | 2024 |
| STG Roofing Limited | Construction | 2024 |
| Sticker Gold Ltd | Manufacturing | 2025 |
| Stiga Ltd | Wholesale & retail | 1972 |
| Stingray Leisure Limited | Hospitality | 2008 |
| Stingray Property Limited | Real estate | 2024 |
| Stone & Sky Ltd | Professional & scientific | 2025 |
| Stone Carter Search Limited | Information & communication | 2013 |
| Stones Rock Ltd | Professional & scientific | 2019 |
| Stopping GAS Ltd | Other services | 2025 |
| Store and Hire Ltd | Transport & logistics | 2024 |
| Stormworks Limited | Construction | 2020 |
| Stort Biltong Ltd | Hospitality | 2021 |