| Tyne & Tees Renewables Group Ltd | Construction | 2025 |
| Tyne-Tees Ropes Rigging & Access Services Ltd | Construction | 2023 |
| Type Five Ltd | Information & communication | 2022 |
| Tyrala Holdings Limited | Financial services | 2016 |
| Tyrala Limited | Wholesale & retail | 2022 |
| Tyrala Property Limited | Construction | 2022 |
| TYW Consulting Ltd | Wholesale & retail | 2018 |
| U Glow Limited | Wholesale & retail | 2019 |
| U Hold the Key Self Storage Ltd. | Real estate | 2001 |
| U Santanera & Associates Limited | Professional & scientific | 2014 |
| U.C. Intelligence Ltd. | Information & communication | 2015 |
| UAS Inspection Services Ltd | Professional & scientific | 2024 |
| Ubeautyaesthetics Ltd | Health & social care | 2018 |
| Ubiquitous Services Ltd | Other services | 2024 |
| Udope Limited | Health & social care | 2026 |
| Uglowtan Ltd | Wholesale & retail | 2025 |
| Ugolis Ltd | Health & social care | 2008 |
| UH Cardiac Diagnostics Ltd | Health & social care | 2022 |
| UK & Ireland SAP User Group Limited | Other services | 2000 |
| UK Checking Services Ltd | Administrative & support | 2019 |
| UK Construction Contracts Limited | Construction | 2011 |
| UK Dairy Sales Limited | Wholesale & retail | 2010 |
| UK Engineering Hub Ltd | Professional & scientific | 2023 |
| UK Gutter Maintenance Ltd | Administrative & support | 2008 |
| UK Health & Safety Services Ltd | Administrative & support | 2009 |
| UK Lifting Solutions Limited | Administrative & support | 2023 |
| UK National Holding Company Limited | Financial services | 2023 |
| UK Nexmove Limited | Transport & logistics | 2026 |
| UK Supplies Worldwide Ltd | Wholesale & retail | 2016 |
| UK Tankcleaning Holdings Limited | Financial services | 2021 |
| UK Tankcleaning Properties Limited | Real estate | 2018 |
| UK Tankcleaning Services Limited | Administrative & support | 2007 |
| UK Vape Supply Ltd | Wholesale & retail | 2016 |
| UK4PADEL Ltd | Real estate | 2026 |
| Ukforward Ltd | Construction | 2022 |
| Ukftis Ltd | Professional & scientific | 2014 |
| Ulta Build Maintenance North East Ltd | Construction | 2023 |
| Ultimate Access Ltd | Professional & scientific | 2023 |
| Ultimate Grooming Middlesbrough Ltd | Other services | 2024 |
| Ultimate Grooming Products Ltd | Other services | 2020 |
| Ultimate Windows (NE) Ltd | Construction | 2008 |
| Ultra Chique Clinique Limited | Other services | 2013 |
| Unbelievabullz Teesside Ltd | Agriculture & fishing | 2020 |
| Unearthed Worksurfaces Ltd | Manufacturing | 2025 |
| Unicorn Commercial Broker Limited | Financial services | 2019 |
| Unicorn Contracts Ltd | Professional & scientific | 2016 |
| Unicorn Skipton Limited | Hospitality | 2014 |
| Uniduo Group Ltd | Wholesale & retail | 2025 |
| Unified Media Films Ltd | Information & communication | 2015 |
| Unio Search Ltd | Administrative & support | 2023 |
| Union Supplier Co Ltd | Wholesale & retail | 2026 |
| Unite Capital Limited | Financial services | 2022 |
| Unite Family One Limited | Financial services | 2025 |
| Unite Family Two Limited | Financial services | 2025 |
| Unite Holdings Group Limited | Professional & scientific | 2022 |
| Unite Investments (UK) Ltd | Construction | 2020 |
| Unite Projects Limited | Financial services | 2021 |
| United British Caravans Limited | Wholesale & retail | 2006 |
| Unitrek Ltd | Information & communication | 2022 |
| Unity Trade Hub UK Ltd | Wholesale & retail | 2026 |
| Unity Transformations Ltd | Arts & recreation | 2024 |
| Universal Axess Limited | Construction | 2026 |
| Universal Garage 2015 Limited | Financial services | 2015 |
| Universal Lifts Limited | Extraterritorial | 1994 |
| Universal Valves Limited | Professional & scientific | 2022 |
| UNO Momento Durham Limited | Hospitality | 2017 |
| Unorthodox Marketing Ltd | Professional & scientific | 2019 |
| Unsponsored Limited | Education | 2015 |
| Unvale Aesthetics Ltd | Other services | 2024 |
| UP in Smoke Vapes Norton Ltd | Wholesale & retail | 2023 |
| Urban Crust Coffee Ltd | Manufacturing | 2026 |
| Urban Evolution Ltd | Construction | 2005 |
| Urban Kaos CIC | Arts & recreation | 2025 |
| Uriel Luxe Living Ltd | Financial services | 2025 |
| Urwater Ltd | Financial services | 2022 |
| UTB Enterprises Ltd | Information & communication | 2026 |
| UTB Training Services Ltd | Education | 2022 |
| Utility Alliance Ltd | Energy | 2015 |
| Utility Services (N.E.) Limited | Construction | 2005 |
| V I Keys Bradford Limited | Professional & scientific | 2018 |
| V I Keys Limited | Administrative & support | 2020 |
| V.I.Keys Property Services Limited | Real estate | 2012 |
| V.I.Keys Stockton Limited | Real estate | 2016 |
| Valencia Marketing Ltd | Manufacturing | 2018 |
| Vallsense Limited | Professional & scientific | 2025 |
| Valmont Stainton Limited | Manufacturing | 1999 |
| Valt Enterprises Ltd | Arts & recreation | 2019 |
| Value Craft Limited | Professional & scientific | 2024 |
| Valuframe Group Limited | Other services | 2012 |
| Valuframe Ltd | Wholesale & retail | 2019 |
| Vane Arms Thorpe Thewles Limited | Hospitality | 2019 |
| Vanta AI Ltd | Information & communication | 2025 |
| Vapes Italia H Ltd | Wholesale & retail | 2025 |
| Vapex Mobile Studio Limited | Wholesale & retail | 2025 |
| Vario’S Pizza and Grill Ltd | Hospitality | 2025 |
| Varo Rolling Stock Ltd | Transport & logistics | 2025 |
| Vault Motors Ltd | Wholesale & retail | 2025 |
| Vaulta Security Ltd | Administrative & support | 2026 |
| Vayu Technology Limited | Information & communication | 2010 |
| VB Digital Marketing Limited | Professional & scientific | 2022 |