| Sonicnet Limited | Administrative & support | 2013 |
| Sons of INK Ltd | Other services | 2020 |
| Sound UN- Limited | Information & communication | 2014 |
| Southeast Mobile Marine Services Ltd | Manufacturing | 2025 |
| Spa Where YOU ARE Limited | Other services | 2017 |
| Spacelion Limited | Information & communication | 2010 |
| Specificity 55 Ltd | Hospitality | 2018 |
| Spectrum 360 Travel Ltd. | Administrative & support | 2018 |
| Spectrum Commerce Limited | Wholesale & retail | 2022 |
| Sphere Science Limited | Education | 2000 |
| Spirited Projects Ltd | Construction | 2021 |
| Spiskula Consulting Limited | Information & communication | 2017 |
| Springer Management Information & Analytics Ltd | Information & communication | 2022 |
| Springer Rock Limited | Real estate | 2019 |
| Springer Rock Tring Projects Ltd | Real estate | 2025 |
| Squad Sports Limited | Professional & scientific | 2016 |
| Square Mile Builders Limited | Construction | 2016 |
| Square Pixel Ltd | Information & communication | 2016 |
| SR Analytics Limited | Information & communication | 2017 |
| ST Albans Gymnastics Club CIC | Arts & recreation | 2014 |
| Stagehand Film and Media Limited | Construction | 2022 |
| Stand Well Care Ltd | Manufacturing | 2017 |
| Start in Morocco Films Limited | Information & communication | 2009 |
| Start the Ripples Ltd | Other services | 2021 |
| Startagen Limited | Construction | 2017 |
| Steel Creative Network Limited | Professional & scientific | 2021 |
| Stefeldann Business Applications Ltd | Information & communication | 2012 |
| Stellar Penguin Ltd | Information & communication | 2024 |
| Stephen Beeny Ltd | Administrative & support | 2023 |
| Sterling Property Group Limited | Real estate | 2013 |
| Steven Campbell Ltd | Professional & scientific | 2018 |
| Stewart Consulting Services Limited | Information & communication | 2022 |
| Stillwell Solutions Ltd | Information & communication | 2013 |
| Stocks Farm Management Limited | Professional & scientific | 2005 |
| Stocks Golf Club LLP | | 2006 |
| Stone Cold Tattoo Collective Ltd | Arts & recreation | 2024 |
| Strategy Synthesis LAB Ltd | Professional & scientific | 2026 |
| Street Foods of India Ltd | Hospitality | 2023 |
| Studham Limited | Administrative & support | 2005 |
| Studio Bloom PR & Communications Ltd | Administrative & support | 2016 |
| Studio Thirtyfour Holdings Ltd | Information & communication | 2023 |
| Studio Thirtyfour Ltd | Information & communication | 2018 |
| Studio Xuto Ltd | Households | 2013 |
| Stylish Shutters Ltd | Wholesale & retail | 2014 |
| Stütz Ltd | Information & communication | 2025 |
| Sublime Build Limited | Construction | 2025 |
| Subsea Couplings Limited | Manufacturing | 2011 |
| Subsea Critical Logistics Limited | Transport & logistics | 2025 |
| Summers BI Solutions Limited | Professional & scientific | 2016 |
| Suncity Properties Limited | Real estate | 2003 |
| Sundon Park Electrical Contractors in Automation Limited | Construction | 2000 |
| Sunny Days Creative Ltd | Professional & scientific | 2022 |
| Sunshine Punch International Ltd | Wholesale & retail | 2026 |
| Sunsible LLP | | 2017 |
| Super Saiyan Safety Ltd | Public administration | 2023 |
| Superchiu Limited | Information & communication | 2021 |
| Sureline Communications Limited | Information & communication | 2008 |
| Susan Hickey Consulting Limited | Professional & scientific | 2023 |
| Sustainable Workflows Ltd | Information & communication | 2024 |
| SWC Consultancy Ltd | Professional & scientific | 2025 |
| Swigwell Wigo Limited | Hospitality | 2025 |
| SWJ Fabrications Limited | Arts & recreation | 2024 |
| SWT Metal Work Limited | Manufacturing | 2016 |
| Sylogy Projects Limited | Administrative & support | 2025 |
| Symonds Consulting Ltd | Professional & scientific | 2026 |
| Symphony Productions Ltd | Arts & recreation | 2024 |
| Systema Solutions Limited | Information & communication | 2008 |
| T C Image Capture Ltd | Information & communication | 2010 |
| T P Engineering Services LLP | | 2005 |
| T&S (Tring) Limited | Hospitality | 2009 |
| T. J. Meacock Ltd | Professional & scientific | 2024 |
| T.W. Generators - South Limited | Manufacturing | 2025 |
| TA CRM Solutions Limited | Information & communication | 2014 |
| Take One Agency Limited | Arts & recreation | 2016 |
| Talentmatched.Com Limited | Administrative & support | 2025 |
| Talentscope Limited | Professional & scientific | 2019 |
| TAN Hub Global Ltd | Other services | 2026 |
| Tangled Data Ltd | Information & communication | 2018 |
| Tape Specialities Limited | Wholesale & retail | 1996 |
| Tapirs Technologies Limited | Information & communication | 2017 |
| Taylor Family Developments Ltd | Real estate | 1926 |
| Taylor Social Co Limited | Professional & scientific | 2021 |
| Taylored Software Solutions Limited | Information & communication | 2019 |
| Teammates App Ltd | Information & communication | 2026 |
| Technica One Projects Limited | Wholesale & retail | 2018 |
| Technology Software Services Limited | Information & communication | 2021 |
| TED Bianco Consulting Ltd | Health & social care | 2015 |
| Temple of Elektra Ltd | Hospitality | 2023 |
| TEN Four Communications Limited | Professional & scientific | 2018 |
| Tentopiauk Ltd | Administrative & support | 2023 |
| Test Management Systems Ltd | Information & communication | 2016 |
| TG Garden Maintenance Ltd | Professional & scientific | 2025 |
| Thank YOU Healthcare Staff | Other services | 2024 |
| THC Sound Limited | Information & communication | 2014 |
| THE AES Tring Park School Trust | Education | 1994 |
| THE Barber Envy Limited | Other services | 2023 |
| THE Barking Brew Ltd | Other services | 2020 |
| THE Bayer Brand Ltd | Wholesale & retail | 2024 |
| THE Beauty Retreat Tring Ltd | Other services | 2024 |
| THE Bell Bovingdon Ltd | Hospitality | 2018 |