| THE Masters Series Limited | Arts & recreation | 1998 |
| THE Milton Keynes Theatre of Comedy Limited | Arts & recreation | 2003 |
| THE Office Hub Olney Ltd | Real estate | 2018 |
| THE Olney Works Ltd | Real estate | 2014 |
| THE Padel Paddock Ltd | Arts & recreation | 2025 |
| THE Physique Project Limited | Arts & recreation | 2025 |
| THE Private Dental Group Limited | Health & social care | 2016 |
| THE Red Thread Fellowship Ltd | Other services | 2019 |
| THE Red Thread Partnership Limited | Professional & scientific | 2013 |
| THE Right Honourable Recording Company Ltd | Information & communication | 2013 |
| THE Snowball Effect Limited | Information & communication | 2007 |
| THE Swan Olney Limited | Hospitality | 2014 |
| Thea Grogan Limited | Information & communication | 2007 |
| Thistlebrook Limited | Construction | 1991 |
| Thomson & Lamb Hairdressing Limited | Other services | 2020 |
| Thrive Medical Group Ltd | Health & social care | 2026 |
| Thrive MS Ltd | Education | 2021 |
| Thunder Races Ltd | Arts & recreation | 2024 |
| Tickford Security Systems Limited | Administrative & support | 2002 |
| TIQ Consultancy Ltd | Professional & scientific | 2015 |
| TMI4 Limited | Administrative & support | 2004 |
| Tmma Properties Ltd | Households | 2025 |
| Tmsl Limited | Professional & scientific | 2012 |
| TNS Business Development Ltd | Professional & scientific | 2024 |
| Tocach Limited | Arts & recreation | 2025 |
| Tonemar Developments Ltd | Wholesale & retail | 2020 |
| Total Tension Solutions Limited | Manufacturing | 1994 |
| Townsend Plumbing Ltd | Construction | 2024 |
| Townsin Limited | Professional & scientific | 2003 |
| Tracey Mann Consulting Ltd | Professional & scientific | 2021 |
| Training With Impact Limited | Professional & scientific | 2004 |
| Treo Strategic Consulting Ltd | Administrative & support | 2021 |
| Trifekka Limited | Hospitality | 2018 |
| TTS Systems Limited | Extraterritorial | 2017 |
| Turquoise & Arboy Limited | Construction | 2007 |
| Twigden Asset Management Limited | Financial services | 2003 |
| TWS Sheq Services Ltd | Public administration | 2017 |
| Txrc Ltd | Manufacturing | 2023 |
| U K Exchangers Ltd | Manufacturing | 1994 |
| Ubortech Limited | Construction | 1997 |
| Udder Interests Limited | Administrative & support | 2005 |
| UK Heat Exchangers Ltd | Manufacturing | 2019 |
| Underneath the Arches Limited | Administrative & support | 2021 |
| Vahine FM Limited | Professional & scientific | 2017 |
| Vava Ltd | Wholesale & retail | 2020 |
| Velotech Cycling Limited | Other services | 2008 |
| Ventura Networks Limited | Information & communication | 2018 |
| Vigga Limited | Arts & recreation | 2019 |
| Vision Walls Ltd | Construction | 2021 |
| Visionary Data Ltd | Information & communication | 2024 |
| Vivhok Ltd | Professional & scientific | 2025 |
| W Squared Limited | Information & communication | 1996 |
| W. Needham & Sons Farming Limited | Agriculture & fishing | 1985 |
| W. Needham & Sons Limited | Professional & scientific | 2013 |
| W. Needham Business Properties Limited | Real estate | 2013 |
| Walton House Property Management Company Limited | Households | 2025 |
| Wandylaw Farming Limited | Agriculture & fishing | 2017 |
| Waseema Holdings Ltd | Financial services | 2024 |
| Waseema Packaging Limited | Wholesale & retail | 2010 |
| Waterloo Mortgages Ltd | Financial services | 2021 |
| Way 2 Mortgage Ltd | Financial services | 2021 |
| Webfox Digital Limited | Information & communication | 2023 |
| Webster Old Masters Limited | Wholesale & retail | 2026 |
| Wembley Lighting Limited | Extraterritorial | 2006 |
| Weston Wind Limited | Energy | 2010 |
| White and Company (Holdings) Limited | Financial services | 2025 |
| White and Company Olney Limited | Real estate | 2001 |
| Whitrust Limited | Real estate | 2002 |
| Wolverton Rail Limited | Wholesale & retail | 1995 |
| Wonderberry Limited | Real estate | 1995 |
| Woodhouse & Cross Limited | Extraterritorial | 2009 |
| Wordsmart Ltd | Professional & scientific | 2022 |
| WS Building Services (Northants) Limited | Construction | 2019 |
| XML Controls Limited | Information & communication | 2021 |
| Young Jedi Solutions Limited | Information & communication | 2002 |
| Zeno Construction Limited | Construction | 2022 |
| Zeno Facades Ltd | Construction | 2025 |
| Zusha Limited | Other services | 2018 |