| Star Samra Limited | Hospitality | 2022 |
| STC Pipefitting Ltd | Transport & logistics | 2024 |
| Stinson Digital Consulting Ltd | Professional & scientific | 2025 |
| Strategically Creative Ltd | Professional & scientific | 2017 |
| Stratton Analytics Ltd | Information & communication | 2025 |
| Stride Small Animal Surgery Ltd | Professional & scientific | 2026 |
| String Telco Ltd | Information & communication | 2026 |
| Studio Hayward Limited | Professional & scientific | 2016 |
| Studio JQ Ltd | Construction | 2016 |
| Stva Construction Limited | Professional & scientific | 2024 |
| Sunforce Services PVT Ltd | Professional & scientific | 2013 |
| Sunnies Limited | Wholesale & retail | 2022 |
| Super Oven Clean Limited | Professional & scientific | 2019 |
| Supersine Ltd | Arts & recreation | 2024 |
| Superstar Katie Limited | Health & social care | 2023 |
| SUPPORT2BUSINESS Limited | Administrative & support | 2001 |
| Susie Freeman Travel Limited | Administrative & support | 2014 |
| Sustain Brokers Limited | Financial services | 2022 |
| Sustainable Wedding Association Ltd | Professional & scientific | 2020 |
| Swan Court Management (Newbury) Limited | Households | 1986 |
| Swan Mill (Newbury) Management Company Limited | Households | 2015 |
| Swift One Holdings Limited | Hospitality | 2016 |
| Swiftbar Limited | Hospitality | 2014 |
| Swinbrook Park (Carterton) Management Company Limited | Households | 2015 |
| SZR Psychology Ltd | Professional & scientific | 2022 |
| T & M (Fasteners & Fixings) Limited | Wholesale & retail | 1995 |
| Tabletrips Ltd | Administrative & support | 2025 |
| Tarco Consulting Limited | Information & communication | 2005 |
| Target Networks Limited | Professional & scientific | 2022 |
| Taslima Catering Ltd | Hospitality | 2024 |
| Tax Wise Services Limited | Professional & scientific | 2024 |
| Taylor Contract Services Limited | Construction | 2023 |
| TC Aviation Services Ltd | Manufacturing | 2018 |
| Teachers and General Investment Company Limited(The) | Real estate | 1889 |
| Teal House Management Company Limited | Professional & scientific | 2008 |
| TEC - the Exhaust Company Limited | Manufacturing | 2021 |
| Techsolv Ltd | Information & communication | 2012 |
| Teddington Enterprises Limited | Other services | 2015 |
| Temp Ctrl Ltd | Professional & scientific | 2026 |
| Tera-Com Limited | Information & communication | 2021 |
| Tfind Ltd | Hospitality | 2026 |
| Tgsk Ltd | Wholesale & retail | 2025 |
| Thames Groundworks Ltd | Construction | 2018 |
| Thames Valley Consultancy Ltd | Information & communication | 2010 |
| That Salon Limited | Other services | 2009 |
| Thatcham Mobility Ltd | Wholesale & retail | 2010 |
| THE Anders Foundation | Professional & scientific | 2012 |
| THE ARK Dog Daycare Ltd | Other services | 2025 |
| THE Bakerteers LLP | | 2017 |
| THE Blue Ball PUB Ltd | Hospitality | 2025 |
| THE Car Filming Safety GUY Ltd | Information & communication | 2020 |
| THE Chase (Newbury) Management Company Limited | Households | 2021 |
| THE Creative Door Company Ltd | Professional & scientific | 2026 |
| THE Definitive Collective Limited | Construction | 2025 |
| THE Dlux Club Ltd | Wholesale & retail | 2021 |
| THE Dog Physio Ltd | Professional & scientific | 2025 |
| THE Downgate PUB Ltd | Hospitality | 2022 |
| THE Downland Partnership Limited | Professional & scientific | 1999 |
| THE East Garston PUB Company Limited | Hospitality | 2015 |
| THE Etis Group Ltd | Hospitality | 2023 |
| THE Experience Design Hub Ltd | Professional & scientific | 2019 |
| THE Fabb Group Ltd | Financial services | 2013 |
| THE Farnham Wine Yard Limited | Wholesale & retail | 2020 |
| THE Filthy RAT Limited | Hospitality | 2025 |
| THE Finance HUT Ltd | Financial services | 2021 |
| THE Fishery (Donnington) Limited | Real estate | 2013 |
| THE Good Guest Company Limited | Wholesale & retail | 2011 |
| THE Institute of Licensed Trade Stock Auditors Ltd | Administrative & support | 1953 |
| THE Paddocks (Southmoor) Management Company Limited | Households | 2016 |
| THE Pink Door Limited | Other services | 2014 |
| THE Plough Operating Company Limited | Hospitality | 2026 |
| THE Plume of Hungerford Ltd | Hospitality | 2019 |
| THE Rufus Coffee House Limited | Hospitality | 2022 |
| THE Scandinavian Camper Van Company Limited | Wholesale & retail | 2021 |
| THE Sleepy PUB Co Limited | Hospitality | 2024 |
| THE Sustainable Apple Spirit Co. Ltd | Wholesale & retail | 2022 |
| THE Tally HO Community PUB Ltd | Hospitality | 2012 |
| THE Tanyard Management Company Limited | Households | 1996 |
| THE Tasting Barn Ltd | Wholesale & retail | 2014 |
| THE Tiny Tasting Room Ltd | Hospitality | 2021 |
| THE Tourbus Company Ltd | Transport & logistics | 2009 |
| THE Vapers Cave Limited | Wholesale & retail | 2017 |
| THE Very Lucky Investment Club LLP | | 2021 |
| THE Village Chippy (Shrewsbury) Limited | Hospitality | 2016 |
| THE Weather Sealing Company Ltd | Construction | 2025 |
| THE Wellbeing Project (Europe) Limited | Professional & scientific | 2007 |
| THE Wellbeing Project Limited | Extraterritorial | 2021 |
| THE Wright Group (South) Ltd | Manufacturing | 2024 |
| These Nutz Ltd | Hospitality | 2026 |
| Think Again Limited | Education | 2004 |
| Think Money Management Limited | Financial services | 2016 |
| Thor Design and Technology Limited | Manufacturing | 2015 |
| Ticketer Limited | Administrative & support | 2009 |
| Time to BE Happy Again Limited | Information & communication | 2025 |
| Timeless Land (Swindon) Limited | Financial services | 2024 |
| Titcomb Investments Limited | Professional & scientific | 2016 |
| TK Brickwork Limited | Construction | 2020 |
| TKP Group Holdings Ltd | Financial services | 2022 |
| TKP Surfacing Limited | Construction | 1997 |
| Tobex Exhibitions Limited | Construction | 2020 |