| Steel Electrical Ltd | Construction | 2018 |
| Stenson Ltd | Administrative & support | 2023 |
| Sterlingax Properties Ltd | Real estate | 2024 |
| Steve Hefna Film Services Ltd | Information & communication | 2017 |
| STM Bros Food Limited | Wholesale & retail | 2014 |
| Stonebid Holdings Limited | Real estate | 2025 |
| Storybun Ltd | Information & communication | 2025 |
| Strawberry Woods Limited | Real estate | 2010 |
| Studioeleven Entertainment Ltd | Information & communication | 2024 |
| Studland Property Limited | Hospitality | 2021 |
| Sunbeam Fostering (Northwest) Limited | Health & social care | 2021 |
| Sunco Construction Ltd | Real estate | 2015 |
| Sunny Physio Ltd | Health & social care | 2025 |
| Sunnyside Private Nursing Home Limited | Health & social care | 1983 |
| Sunstripe Limited | Real estate | 1993 |
| Suntek Technology Services Limited | Information & communication | 2011 |
| Sunwave Limited | Information & communication | 2018 |
| Super Car Logistics Limited | Wholesale & retail | 2009 |
| Super Flow Plumbing & Drainage Ltd | Water & waste | 2019 |
| Surey Properties Limited | Real estate | 2022 |
| Suri Design and Build Ltd | Construction | 2024 |
| Susang Transport Ltd | Transport & logistics | 2022 |
| Suvac Ltd | Construction | 2025 |
| Swaad Spot Iver Ltd | Hospitality | 2025 |
| Swains Services Limited | Real estate | 1988 |
| Swallow Fields (Iver) Management Company Limited | Households | 2007 |
| SWALLOW1820 Ltd | Households | 2016 |
| Swaranjali Ltd | Arts & recreation | 2025 |
| Sweet Electricals Ltd | Construction | 2024 |
| Swhitfieldpsychology Ltd | Education | 2021 |
| Swift AOG Ltd | Transport & logistics | 2024 |
| Sygenta Limited | Professional & scientific | 2001 |
| Sylhety Spice Ltd | Hospitality | 2016 |
| Synergies IT Solutions Ltd | Information & communication | 2026 |
| T.H Real Estate Services Ltd | Real estate | 2019 |
| T.W.G. International Ltd | Health & social care | 2021 |
| Taas Transport Ltd | Water & waste | 2019 |
| Talking Business (Office Supplies) Limited | Wholesale & retail | 1999 |
| Talwar Investments Ltd | Real estate | 2020 |
| Tate Freight Systems Limited | Transport & logistics | 2023 |
| Tcat Omip Limited | Information & communication | 2017 |
| Tcde Ltd | Professional & scientific | 2022 |
| Tchadimas Limited | Real estate | 2021 |
| Teachers That Tutor Ltd | Education | 2020 |
| Tels Scaffolding Services Ltd | Construction | 2025 |
| Templewood Clinic Limited | Health & social care | 2020 |
| Teppanice Ltd | Wholesale & retail | 2017 |
| Terra Limited | Real estate | 2000 |
| TGE Associates Limited | Professional & scientific | 2004 |
| TGM Management Consultancy Limited | Information & communication | 2022 |
| TH Sports Turf Solutions Ltd | Professional & scientific | 2024 |
| THE Beluga Cafe Ltd | Hospitality | 2011 |
| THE Better Water Company Limited | Wholesale & retail | 2025 |
| THE Boatman's Cabin Co. Limited | Manufacturing | 1987 |
| THE Brand Architekts Limited | Administrative & support | 2007 |
| THE Driveteam International Limited | Administrative & support | 2019 |
| THE Genesys Power Company Limited | Information & communication | 2016 |
| THE GLO Bar Skincare Limited | Other services | 2023 |
| THE Indoor Golf Club Ltd | Arts & recreation | 2023 |
| THE Jewel JAR Ltd | Wholesale & retail | 2021 |
| THE LEG Partnership Limited | Hospitality | 2015 |
| THE Londoneer Ltd | Real estate | 2023 |
| THE Marwari Club Ltd | Wholesale & retail | 2025 |
| THE Obgyn Edit Ltd | Education | 2025 |
| THE Richings Group Limited | Real estate | 2023 |
| THE Richings Park Pavilion Ltd | Arts & recreation | 2025 |
| THE Richings Park Sports Pavilion Limited | Arts & recreation | 2025 |
| THE Sanctuary Beauty Salon Limited | Other services | 2020 |
| THE Wardrobe Company Herts Ltd | Construction | 2020 |
| THE Wedding Treasurer Ltd | Professional & scientific | 2021 |
| THE WIG Store Limited | Administrative & support | 2008 |
| THE Yard Storage Ltd | Arts & recreation | 2026 |
| Thegreasemonkey Ltd | Wholesale & retail | 2011 |
| Theidealgarden.Com Ltd | Wholesale & retail | 2022 |
| They Manage Limited | Real estate | 2024 |
| Thorney Court Management Company Limited | Administrative & support | 1997 |
| Three Spires Acoustics Ltd | Administrative & support | 2007 |
| Three Valleys Properties Limited | Construction | 2025 |
| Thud Services Ltd | Manufacturing | 2011 |
| Thunderstorm Roofing Solutions Ltd | Construction | 2025 |
| Tigris 2017 Limited | Real estate | 2017 |
| Tilesright Limited | Wholesale & retail | 2024 |
| Tinge Investments Ltd | Real estate | 2016 |
| Tinge Ltd | Real estate | 2015 |
| Tint & Tapestry Ltd | Wholesale & retail | 2025 |
| Tintop Fitness Ltd | Arts & recreation | 2026 |
| Tithe Barn Estates Limited | Real estate | 2016 |
| TJ Commercial Ltd | Wholesale & retail | 2026 |
| TJ Plaster Limited | Construction | 2017 |
| TK Property Investment Limited | Real estate | 2016 |
| Tommy Rose Limited | Information & communication | 2008 |
| Tothedot Limited | Real estate | 2025 |
| Trade in ALL Ltd | Wholesale & retail | 2025 |
| Trademark Development Ltd | Construction | 2019 |
| Training Link Europe Limited | Education | 2001 |
| Training Match Ltd | Transport & logistics | 2016 |
| Trans-Uk Supplies Limited | Wholesale & retail | 1992 |
| Translux International Limited | Information & communication | 1989 |
| Travel Health Limited | Health & social care | 2019 |
| Treasured Scents (2014) Limited | Administrative & support | 2014 |