| Stakeout Engineering Ltd | Construction | 2022 |
| Station Road Chippy (March) Limited | Hospitality | 2023 |
| Stealth Group Ventures Ltd | Financial services | 2025 |
| Steepleview Roofing Ltd | Construction | 2014 |
| Stellar Capital Limited | Administrative & support | 2019 |
| Stellar Commercial Limited | Financial services | 2024 |
| Stellar Immigration Services Ltd | Professional & scientific | 2021 |
| Stellar Law Ltd. | Financial services | 2008 |
| Stellar Property Developments Limited | Financial services | 2024 |
| Stellar Property Spain Ltd | Financial services | 2025 |
| Stellar Studios Co Limited | Wholesale & retail | 2025 |
| Steve Hudson & Sons Limited | Construction | 2025 |
| Stewart Thomas Solutions Ltd | Transport & logistics | 2024 |
| Stokes & SON Limited | Manufacturing | 2002 |
| Stone Cross Publishing Limited | Information & communication | 2002 |
| Stott's Fish Restaurant Limited | Hospitality | 2002 |
| Street Plumbing & Heating Ltd | Extraterritorial | 2023 |
| Strong Barber Ltd | Other services | 2025 |
| Suction Excavation UK Limited | Construction | 2017 |
| Sunkissed (March) Ltd | Other services | 2022 |
| Sunlounger Travel (KL) Ltd | Administrative & support | 2020 |
| Sunlounger Travel (Wisbech) Ltd | Administrative & support | 2019 |
| Sunlounger Travel Group Ltd | Administrative & support | 2019 |
| Sunygraphics.Co.Uk Limited | Professional & scientific | 2023 |
| Swift Stay Ltd | Real estate | 2018 |
| Swimbler Limited | Wholesale & retail | 2021 |
| T L Productions Limited | Manufacturing | 2007 |
| T L Property Holdings Ltd | Real estate | 2022 |
| T Shepperson Contracting Ltd | Agriculture & fishing | 2024 |
| T.A.P (March) Limited | Hospitality | 2024 |
| Tap.That.March. Limited | Arts & recreation | 2022 |
| Task F Limited | Professional & scientific | 2013 |
| Tattoo Crazy Limited | Other services | 2003 |
| Taurus Contracting Ltd | Construction | 2022 |
| Taurus Estate Group Limited | Real estate | 2021 |
| Taymor Plumbing Supplies Limited | Wholesale & retail | 2002 |
| TEE & Co Investments Limited | Health & social care | 2018 |
| Tempstop Ltd | Administrative & support | 2009 |
| TES Farm Holdings Ltd | Financial services | 2024 |
| Teversham Precision Engineering Limited | Manufacturing | 2016 |
| Thatmealapp Ltd | Wholesale & retail | 2026 |
| THE Active Learning Trust Limited | Education | 2012 |
| THE Autobarn @ Mill Hill Ltd | Wholesale & retail | 2023 |
| THE Business Index Ltd | Professional & scientific | 2007 |
| THE Construction Index Ltd | Professional & scientific | 2007 |
| THE Cosmic Dog Ltd | Wholesale & retail | 2025 |
| THE Entertainment Consultancy LLP | | 2020 |
| THE Environmental Auditors Registration Association | Other services | 1992 |
| THE Exchange (March) Ltd | Hospitality | 2016 |
| THE Fisher Parkinson Trust Limited | Professional & scientific | 2006 |
| THE Golden FRY 14 Ltd | Hospitality | 2026 |
| THE Gutter Clean Company Ltd | Administrative & support | 2025 |
| THE Handy Garden MAN Fencing Company Ltd | Construction | 2024 |
| THE Institute of Environmental Assessment | Other services | 1990 |
| THE Institute of Sustainability and Environmental Professionals | Other services | 1998 |
| THE March Carpet Warehouse Limited | Wholesale & retail | 2022 |
| THE Old Dairy Yards Estates Ltd | Real estate | 2024 |
| THE Plastering Worx Ltd | Construction | 2023 |
| THE Rebirth Collective Ltd | Arts & recreation | 2026 |
| THE Red Lion (March) Limited | Hospitality | 2018 |
| THE Renewables Company (Cambs) Limited | Construction | 2025 |
| THE Rose Tattoo Studio Limited | Arts & recreation | 2005 |
| THE Wheel Centre Enterprises Limited | Financial services | 2020 |
| THE Window and Door Business Ltd | Construction | 2020 |
| THORBYAV1 Ltd | Real estate | 2022 |
| Thorpe Road Residences Limited | Real estate | 2024 |
| Three Counties Training Ltd | Education | 2024 |
| Tiana's Beauty Ltd | Other services | 2024 |
| Tideama Ltd | Wholesale & retail | 2024 |
| TIM Philpott Limited | Construction | 2015 |
| Timelessfloorrestorations Ltd | Construction | 2025 |
| Tintenter Ltd | Professional & scientific | 2019 |
| Titas. Ltd | Administrative & support | 2025 |
| TJR Property Management Ltd | Real estate | 2022 |
| Toge+Her Ltd | Arts & recreation | 2020 |
| Top Notch Tutors Limited | Education | 2016 |
| Top Skim Limited | Construction | 2005 |
| Tops Accounting Ltd | Extraterritorial | 2017 |
| TOR Utilities Ltd | Professional & scientific | 2025 |
| Total Office Refits Limited | Construction | 2019 |
| TPW Developments Limited | Construction | 2021 |
| TPW Electrical Limited | Construction | 2019 |
| Tradelink (Midlands) Limited | Extraterritorial | 1988 |
| Tradelink Direct Limited | Manufacturing | 1991 |
| Tradelink Installations Limited | Construction | 1993 |
| Trading A.S.S Ltd | Administrative & support | 2026 |
| Trainseurope Ltd | Administrative & support | 1987 |
| Triarii Talent Ltd | Administrative & support | 2026 |
| TRM Family Investment Company Limited | Extraterritorial | 2017 |
| TSC Agricultural Services Ltd | Agriculture & fishing | 2024 |
| Tudor Buildings (March) Limited | Real estate | 2013 |
| Tunc DEV Ltd | Information & communication | 2020 |
| Turkish BBQ Flames Ltd | Hospitality | 2022 |
| UK SMR Plant Limited | Manufacturing | 2024 |
| UK Towbars Ltd | Manufacturing | 2009 |
| Ultimate MPR Limited | Manufacturing | 2025 |
| Ultra Clean Pro Ltd | Administrative & support | 2025 |
| Ultra-Align Limited | Manufacturing | 2022 |
| Uncle Mini Ltd | Real estate | 2026 |
| Unearthed Discovery Centre CIC | Arts & recreation | 2020 |