| Superbowl UK Stafford Limited | Arts & recreation | 2023 |
| Superbowl UK Wolverhampton Limited | Arts & recreation | 2024 |
| Support Revolution Investments Ltd | Information & communication | 2012 |
| Support Revolution Limited | Information & communication | 1998 |
| Supreme Legal & Business Ltd | Professional & scientific | 2020 |
| Surgery in Berkshire Limited | Other services | 2010 |
| Sustainable Marine Solutions Ltd | Professional & scientific | 2020 |
| Sustainable Marine Technology Ltd | Professional & scientific | 2021 |
| Sustainable Reporting Solutions Ltd | Professional & scientific | 2025 |
| Sustainable Technology Solutions Ltd | Extraterritorial | 2020 |
| SW Composites Limited | Manufacturing | 2025 |
| SW Nannying Services Limited | Health & social care | 2025 |
| Swatter Prop Ltd | Real estate | 2024 |
| Sweet Imagination Ltd | Wholesale & retail | 2017 |
| Swings & Smiles | Arts & recreation | 2007 |
| Swish Cocktails Ltd | Manufacturing | 2021 |
| Swish Holdings Ltd | Financial services | 2023 |
| Swish Snacks Ltd | Manufacturing | 2023 |
| SX Imaging Limited | Manufacturing | 2012 |
| Synergy Plastering Ltd | Construction | 2020 |
| Systematic Creative Interiors Ltd | Construction | 2005 |
| Syswatch Ltd | Information & communication | 2018 |
| T a Properties Limited | Real estate | 2000 |
| T D Heating Limited | Other services | 2002 |
| T W K Electrical Limited | Energy | 2009 |
| T&M Kitchens and Bedrooms Ltd | Construction | 2012 |
| T.J.M Construction Management Limited | Construction | 2025 |
| T.P.Grange & Co. Ltd | Real estate | 2023 |
| T4 Communications Limited | Information & communication | 2001 |
| T88 TU Limited | Real estate | 2025 |
| T999 Ltd | Wholesale & retail | 2016 |
| TA Consulting Limited | Professional & scientific | 1994 |
| Tabari Trading Ltd | Professional & scientific | 2022 |
| Tace House Management Company Limited | Households | 2023 |
| Tactical Properties Limited | Construction | 1987 |
| Tail Wagging Treats Limited | Wholesale & retail | 2023 |
| Talambo Trans Ltd | Transport & logistics | 2025 |
| Talent Development Services Ltd | Professional & scientific | 2021 |
| Tamcken Investments Ltd | Real estate | 2026 |
| Tamworth Holdings Limited | Financial services | 2021 |
| Tankways Ltd | Professional & scientific | 2017 |
| Tanoti Services Ltd | Information & communication | 2020 |
| Target Fixings Limited | Manufacturing | 1997 |
| Target Structural Ltd | Construction | 2007 |
| Task Right Limited | Wholesale & retail | 2004 |
| Tastely Ltd | Wholesale & retail | 2024 |
| Taylor Made Fabrication Limited | Manufacturing | 1998 |
| TBV Construct Ltd | Wholesale & retail | 2020 |
| TC5 Design Ltd | Administrative & support | 2012 |
| TDL Properties (Sandy Lane) Limited | Construction | 2012 |
| TDL Properties Limited | Construction | 2012 |
| Tea for YOU Limited | Wholesale & retail | 2008 |
| Techcase Ltd | Extraterritorial | 2012 |
| Technocomm Consulting Ltd | Information & communication | 2013 |
| Technocomm-Iot Ltd | Information & communication | 2021 |
| Technology Management Group Limited | Information & communication | 1983 |
| Techpro Solutions Limited | Manufacturing | 2004 |
| Teed UP Limited | Other services | 2024 |
| Tekxt Ltd | Information & communication | 2019 |
| Telepathix Limited | Administrative & support | 2007 |
| Tenaka.Net Ltd | Information & communication | 2023 |
| Tend and Care Ltd | Administrative & support | 2024 |
| Tenuta Marmorelle Limited | Wholesale & retail | 2014 |
| TEV Investment Ltd | Hospitality | 2024 |
| Thatcham 10K Community Interest Company | Arts & recreation | 2024 |
| Thatcham Autocentre Ltd | Wholesale & retail | 2020 |
| Thatcham Court Management Ltd | Real estate | 2019 |
| Thatcham Properties Ltd | Real estate | 2025 |
| Thatcham Stores Limited | Real estate | 2021 |
| Thatcham Tandoori Restaurant UK Ltd | Hospitality | 2026 |
| Thatcham Tandoori Yummy Food Ltd | Hospitality | 2024 |
| Thatcham Van Services Ltd | Transport & logistics | 2025 |
| Thatcham Ventures Limited | Information & communication | 2023 |
| Thatlldo Ltd | Wholesale & retail | 2023 |
| THE Base Greenham | Arts & recreation | 2019 |
| THE BBQ MAG Limited | Information & communication | 2020 |
| THE Berkshire VET Limited | Professional & scientific | 2022 |
| THE Breeze Drinks Company Ltd. | Manufacturing | 2021 |
| THE Brew Basket Limited | Wholesale & retail | 2025 |
| THE Cake Lady of Oxfordshire Ltd | Manufacturing | 2023 |
| THE Carrier Pigeon Ltd | Transport & logistics | 2011 |
| THE Channel Sherpas Ltd | Information & communication | 2025 |
| THE Complete Works Entertainment Limited | Arts & recreation | 1998 |
| THE Connection Psychologist Limited | Health & social care | 2018 |
| THE Cube Farm Limited | Information & communication | 2002 |
| THE Dog Pack Berkshire Ltd | Agriculture & fishing | 2024 |
| THE Drainsquad Limited | Construction | 1996 |
| THE Experiential Travel Group Ltd | Administrative & support | 2015 |
| THE Fireplace Thatcham Limited | Construction | 2011 |
| THE Full Works Valeting Limited | Professional & scientific | 2011 |
| THE Gilded Barber Ltd | Other services | 2020 |
| THE Grassroots Platform Ltd | Arts & recreation | 2024 |
| THE Harrow Property Management Company Limited | Households | 2018 |
| THE Heritage Lime Co. Ltd | Construction | 2024 |
| THE House of Toomer Limited | Construction | 1996 |
| THE HR Alchemist Limited | Professional & scientific | 2002 |
| THE International Exchange Ltd | Administrative & support | 2006 |
| THE Key Clinic Ltd | Administrative & support | 2015 |
| THE LAN Platform Limited | Information & communication | 1996 |
| THE Lemon Rooms Ltd | Professional & scientific | 2026 |