| Ubiq Group Ltd | Professional & scientific | 2018 |
| Ubkb Ltd | Other services | 2016 |
| Ubuningi Ltd | Professional & scientific | 2021 |
| UC197 Limited | Information & communication | 2026 |
| UCS Assist Limited | Administrative & support | 2026 |
| UCS Care Group Limited | Financial services | 2023 |
| UCS Medical Ltd | Health & social care | 2022 |
| UCS Training Ltd | Education | 2023 |
| UDC (NW) Ltd | Hospitality | 2018 |
| Uddish Stores Limited | Wholesale & retail | 2025 |
| Udupa PVT Ltd | Administrative & support | 2025 |
| UG Interiors Ltd | Construction | 2026 |
| UG Rentals Ltd | Administrative & support | 2022 |
| UGO Leisure Ltd | Wholesale & retail | 2019 |
| UI Central Holdings Limited | Construction | 2004 |
| UI Energy & Water Holdco Limited | Financial services | 2025 |
| UI Intermediate II Limited | Financial services | 2023 |
| UI Social Infrastructure Holdco Limited | Financial services | 2025 |
| UI Social Infrastructure Limited | Construction | 1986 |
| UI Telecoms & Power Holdco Limited | Financial services | 2025 |
| UI Utility Infrastructure Holdco Limited | Extraterritorial | 2025 |
| UK Advance Telecommunication Ltd | Information & communication | 2012 |
| UK Artificial Grass Direct Ltd | Manufacturing | 2020 |
| UK Bargain Box Limited | Wholesale & retail | 2025 |
| UK Building Control Limited | Administrative & support | 2025 |
| UK Building Surveys Ltd | Professional & scientific | 2016 |
| UK Car Discount Ltd | Wholesale & retail | 2003 |
| UK Control Panel Services Limited | Manufacturing | 2021 |
| UK Data Solutions Limited | Administrative & support | 2025 |
| UK Fashion for Kids Ltd | Wholesale & retail | 2023 |
| UK Fire & Security Limited | Administrative & support | 2011 |
| UK Fire Consultants Limited | Other services | 2021 |
| UK FM Holdings Limited | Construction | 2023 |
| UK Gases Ltd | Energy | 2021 |
| UK Groundcare Limited | Administrative & support | 2025 |
| UK Locks & Alarms Ltd | Administrative & support | 2015 |
| UK Luxury Construction Ltd | Construction | 2026 |
| UK Mortgage Centre Limited | Other services | 2024 |
| UK Natural Serenity Ltd | Manufacturing | 2018 |
| UK Power Design Ltd | Administrative & support | 2013 |
| UK Road Tanker Inspection Limited | Professional & scientific | 2013 |
| UK Safety Netting Ltd | Construction | 2014 |
| UK Spartan Limited | Real estate | 2021 |
| UK Tax Practice Limited | Professional & scientific | 2003 |
| UK Temper Ltd | Information & communication | 2022 |
| UK Window Tinting Ltd | Professional & scientific | 2023 |
| Uk-Africa Investment Gateway Consultancy Limited | Professional & scientific | 2025 |
| Ukbr Trading Limited | Other services | 2025 |
| UKC Global Ltd | Arts & recreation | 2020 |
| Ukc&E Ltd | Professional & scientific | 2017 |
| UKMC2 Ltd | Financial services | 2022 |
| UKR Group Ltd | Real estate | 2020 |
| Ukspeed Limited | Information & communication | 2023 |
| UL (Bathgate) Limited | Construction | 2024 |
| UL (TBW) Limited | Construction | 2021 |
| Ultimate Breakout Ltd | Arts & recreation | 2021 |
| Ultimate Builder Limited | Construction | 2008 |
| Ultimate Property Limited | Real estate | 2007 |
| Ultra Co Group Holdings Ltd | Financial services | 2024 |
| Ultra Co Group Ltd | Construction | 2023 |
| Ultra Coffee Ltd | Hospitality | 2025 |
| Ultra Couriers Limited | Transport & logistics | 2021 |
| Ultra Decking Ltd | Wholesale & retail | 2021 |
| Ultra Estates Co Ltd | Real estate | 2024 |
| Ultrapace Limited | Information & communication | 2006 |
| Ultrapolymers Limited | Administrative & support | 2002 |
| Ultrarunner Magazine Ltd | Information & communication | 2020 |
| Ultraview Limited | Education | 1988 |
| UM Service and Supply Ltd | Wholesale & retail | 2024 |
| Umami Warrington Limited | Hospitality | 2024 |
| Umbe Health Ltd | Health & social care | 2023 |
| Umbrella Group M&E Ltd | Construction | 2021 |
| Umbrella HR Ltd | Professional & scientific | 2020 |
| Umbrella Property Ltd | Real estate | 2023 |
| UN Copil Ltd | Transport & logistics | 2016 |
| Uncle Ronnies Barber Shop Ltd | Other services | 2025 |
| Uncletak Bakery Ltd | Hospitality | 2024 |
| Under Floor Heating Trade Direct Ltd | Wholesale & retail | 2011 |
| Under the Canopy CIC | Hospitality | 2026 |
| Underhill IT Consulting Limited | Information & communication | 2018 |
| Underneath Lingerie & Accessories Limited | Wholesale & retail | 2025 |
| Underwood Project Services Ltd | Information & communication | 2019 |
| Underwrapsuk Limited | Construction | 2023 |
| Uneeq Kreations Ltd | Other services | 2023 |
| Unicorn Advisory Limited | Professional & scientific | 2017 |
| Uniex Transport Limited | Professional & scientific | 1973 |
| Unified Data Analytics Limited | Information & communication | 2024 |
| Unified IT Solutions Ltd | Other services | 2015 |
| Unifiedvu Ltd | Information & communication | 2014 |
| Unik Glow Aesthetics Ltd | Other services | 2025 |
| Uniloads Limited | Transport & logistics | 1978 |
| Union House Accomodation Services Limited | Hospitality | 1997 |
| Unique Alterations Ltd | Professional & scientific | 2023 |
| Unique Blinds & Shutters NW Limited | Wholesale & retail | 2022 |
| Unique Cleaning Specialists Ltd | Administrative & support | 2024 |
| Unique Flavour Catering Ltd | Hospitality | 2020 |
| Unique Shutter Specialists Ltd | Wholesale & retail | 2023 |
| Unique Tanning and Beauty Ltd | Other services | 2026 |
| Uniskills Limited | Information & communication | 2019 |
| Unit 13 Cockhedge Ltd | Wholesale & retail | 2023 |