| United Flexo Supplies Limited | Wholesale & retail | 2009 |
| United Hair Studio Ltd | Other services | 2024 |
| United Immigration Services Limited | Professional & scientific | 2020 |
| United Kingdom Association of Professional Piercers | Education | 2015 |
| United Merchant Group Ltd | Hospitality | 2020 |
| United Ocean Limited | Health & social care | 2025 |
| United Property Developments Ltd | Real estate | 2017 |
| United Sports Corporation Ltd | Arts & recreation | 2018 |
| Unitility Ltd | Administrative & support | 2025 |
| Unity Block Management Limited | Households | 2026 |
| Unity Coffee Ltd | Hospitality | 2022 |
| Unity Front Property Investments Limited | Real estate | 2024 |
| Unity Gym Ltd | Arts & recreation | 2018 |
| Universal Coaching Limited | Extraterritorial | 2011 |
| Universal Fortune Engineering Services Ltd | Professional & scientific | 2025 |
| Universal Forwarding Limited | Extraterritorial | 2025 |
| Universal Land Developments Limited | Professional & scientific | 1972 |
| Universal Love Ltd | Professional & scientific | 2023 |
| Universal Protective Coatings Limited | Wholesale & retail | 1995 |
| University Centre Quayside Limited | Education | 1997 |
| University of Northumbria at Newcastle Developments Limited | Education | 1997 |
| Uniworld Essentials Limited | Wholesale & retail | 2025 |
| Unjibbed Ltd | Information & communication | 2024 |
| Unlock Music CIC | Arts & recreation | 2021 |
| Unmanned Aviation Ltd | Professional & scientific | 2026 |
| Unravel Data Solutions Ltd | Information & communication | 2023 |
| Unreal Ideal Ltd | Information & communication | 2020 |
| Untemp Ltd | Arts & recreation | 2025 |
| UNW Company Secretary Limited | Extraterritorial | 2016 |
| UNW Consultants Limited | Extraterritorial | 2002 |
| UNW Financial Services Limited | Extraterritorial | 1999 |
| UNW Group Limited | Extraterritorial | 2000 |
| UNW LLP | | 2002 |
| UNW Ltd. | Extraterritorial | 1996 |
| Unwritten Group Limited | Professional & scientific | 2014 |
| UP ALL Neet Ltd | Arts & recreation | 2026 |
| UP North Fibre Limited | Information & communication | 2025 |
| UP North Property Ltd | Real estate | 2025 |
| UP the Hill Limited | Real estate | 2018 |
| Upacare Health Ltd | Health & social care | 2021 |
| UPD Finance Limited | Financial services | 2025 |
| Uphire IQ Limited | Information & communication | 2025 |
| Upnorth Consulting Ltd | Information & communication | 2019 |
| Upnorth Flat Roofing Ltd | Construction | 2019 |
| Upper Limb Surgery Ltd | Health & social care | 2012 |
| Upperbay Limited | Hospitality | 1999 |
| Uprooted INK Ltd | Arts & recreation | 2025 |
| Upshift Store Ltd | Wholesale & retail | 2018 |
| Upstream Global Ventures Limited | Professional & scientific | 2025 |
| Uptin Motors Limited | Wholesale & retail | 1988 |
| Uptivity Limited | Information & communication | 2019 |
| UR Care Solution Ltd | Administrative & support | 2021 |
| Uraltrade Ltd | Wholesale & retail | 2022 |
| Urban Angel Centres Ltd | Health & social care | 2019 |
| Urban Angel Healthcare Ltd | Health & social care | 2023 |
| Urban Business Solutions (UK) Ltd. | Wholesale & retail | 2024 |
| Urban Catering North East Ltd | Hospitality | 2024 |
| Urban Concept (North East) Limited | Other services | 2014 |
| Urban Convenience Ltd | Wholesale & retail | 2022 |
| Urban Cribs Ltd | Real estate | 2023 |
| Urban Foresight Limited | Professional & scientific | 2011 |
| Urban FOX Networks (Herts) Limited | Construction | 2026 |
| Urban FOX Networks (Kent) Limited | Construction | 2026 |
| Urban FOX Networks (Medway) Limited | Construction | 2026 |
| Urban FOX Networks (P&C) Limited | Construction | 2026 |
| Urban FOX Networks (Suffolk) Limited | Construction | 2026 |
| Urban FOX Networks (UK) Limited | Manufacturing | 2023 |
| Urban Future Farm Ltd | Manufacturing | 2020 |
| Urban Landscapes NE Ltd | Administrative & support | 2024 |
| Urban Logistics NE Ltd | Transport & logistics | 2019 |
| Urban Mind CIC | Health & social care | 2021 |
| Urban Nest Developments Ltd | Construction | 2021 |
| Urban Nest Real Estate Limited | Real estate | 2017 |
| Urban Park Market Ltd | Arts & recreation | 2023 |
| Urban Pathways Limited | Wholesale & retail | 2023 |
| Urban Pinnacle Properties Ltd | Real estate | 2024 |
| Urban Residential Ltd | Real estate | 2019 |
| Urban Shopper Ltd | Wholesale & retail | 2023 |
| Urban Sweet Potato Ltd | Households | 2019 |
| Urban Voices Community Media Limited | Information & communication | 2025 |
| Urbanbase Lettings Limited | Real estate | 2005 |
| Urbangoddess Limited | Other services | 2013 |
| Urbanlynx Limited | Real estate | 2026 |
| Urbanmedics Ltd | Wholesale & retail | 2019 |
| Urbanpulse Collective Ltd | Wholesale & retail | 2025 |
| Urbun Properties Ltd | Real estate | 2025 |
| Urhobo Progress Union UK Newcastle Sub-Branch CIC | Hospitality | 2025 |
| URO Life Limited | Health & social care | 2019 |
| Urogenpra Limited | Health & social care | 2025 |
| URS Group of Companies Ltd | Wholesale & retail | 2026 |
| Used Power Generation Ltd | Construction | 2018 |
| Userlab Ltd. | Professional & scientific | 2015 |
| Usmaira Limited | Wholesale & retail | 2024 |
| Usnea Services Limited | Professional & scientific | 2016 |
| Ustirea Ltd | Real estate | 2016 |
| Usworth Hall Management NO. 2 Limited | Hospitality | 2007 |
| Utensilas Global Ltd | Wholesale & retail | 2026 |
| Utex Industries UK Limited | Manufacturing | 2002 |
| Uthman&Bros Ltd | Hospitality | 2024 |
| Utiligensia Limited | Transport & logistics | 2002 |