| Umar Imaging Limited | Health & social care | 2022 |
| Umay Technology Limited | Information & communication | 2022 |
| UMB Trading Limited | Wholesale & retail | 2024 |
| Umbilical Holdings Limited | Administrative & support | 2017 |
| Umbilical Limited | Administrative & support | 2017 |
| Umbrella Research Corporation Ltd | Professional & scientific | 2018 |
| UMBRELLA4ME Ltd | Professional & scientific | 2015 |
| UMD Portfolio Limited | Real estate | 2010 |
| Umera Building Contractor Ltd | Construction | 2025 |
| Umme & Co Ltd | Wholesale & retail | 2025 |
| Umrah Express Wallsall Ltd | Wholesale & retail | 2025 |
| Umrah Supermarket Dewsbury Ltd | Wholesale & retail | 2024 |
| Umrah Supermarket Hastings Ltd | Wholesale & retail | 2023 |
| Umrah Supermarket Leeds Ltd | Wholesale & retail | 2026 |
| Umrah Supermarket Ltd | Wholesale & retail | 2021 |
| Umrah Supermarket Wolverhampton Ltd | Wholesale & retail | 2024 |
| Umug.Com Ltd | Wholesale & retail | 2026 |
| Umxlix Limited | Manufacturing | 2025 |
| UN Academy for Influential Leaders Ltd | Administrative & support | 2025 |
| UN Services Ltd | Transport & logistics | 2016 |
| UNA Management Limited | Construction | 2026 |
| Unbeeweeveable Ltd | Extraterritorial | 2014 |
| Unbiasly Ltd | Information & communication | 2023 |
| Unblockablock Limited | Administrative & support | 2021 |
| Unbox Machine Ltd | Information & communication | 2022 |
| Unbranded Official UK Limited | Wholesale & retail | 2023 |
| Unbreakable Self-Defence C.I.C. | Professional & scientific | 2021 |
| Unchained Music Ltd | Professional & scientific | 2025 |
| Uncle G Ltd | Hospitality | 2026 |
| Uncle J'S Holdings Ltd | Professional & scientific | 2026 |
| Uncleteo Promotions Ltd | Arts & recreation | 2018 |
| Uncovr.Art Limited | Professional & scientific | 2023 |
| Undercover Trading Ltd | Wholesale & retail | 2019 |
| Underdawgz Ltd | Other services | 2024 |
| Underdog Records Limited | Manufacturing | 2007 |
| Underground Stream Ltd | Hospitality | 2025 |
| Underwood Equities Ltd | Financial services | 2025 |
| Underworld Pet Products Limited | Extraterritorial | 2011 |
| UNE March Ltd | Wholesale & retail | 2026 |
| Uneek Branding Ltd | Manufacturing | 2021 |
| Uneeq Clothing Ltd | Manufacturing | 2018 |
| Uneven Camber Limited | Professional & scientific | 2005 |
| Unfiltered Elegance Limited | Wholesale & retail | 2024 |
| Unfitted Ltd | Wholesale & retail | 2011 |
| Unfitted Trustees Limited | Administrative & support | 2022 |
| Ungaro Hair Studies Limited | Other services | 1993 |
| Unhung Ltd | Wholesale & retail | 2025 |
| UNI OFF Licence Leics Ltd | Wholesale & retail | 2020 |
| UNI OFF Licence Ltd | Wholesale & retail | 2018 |
| UNI Store Leics Ltd | Wholesale & retail | 2024 |
| UNI Worx Ltd | Professional & scientific | 2022 |
| Uni.Ms Trading Ltd | Other services | 2018 |
| Unibuild Construction Ltd | Construction | 2016 |
| Unicommerce Technologies Limited | Information & communication | 2025 |
| Unicool (Leicester) Limited | Energy | 2008 |
| Unicorn High Finance Limited | Financial services | 2020 |
| Unicorn P.S.C. Limited | Health & social care | 2002 |
| Unified Bridge Consulting Ltd | Professional & scientific | 2026 |
| Unified Holdings Limited | Financial services | 2020 |
| Unified Marketing Agency, Ltd | Other services | 2023 |
| Uniform Xperts Ltd | Manufacturing | 2022 |
| Unihealth Plus Ltd | Health & social care | 2023 |
| Uniiq Ltd | Wholesale & retail | 2021 |
| Unik (2026) Limited | Wholesale & retail | 2026 |
| Unimed Equa Limited | Professional & scientific | 2025 |
| Unimed Global Limited | Wholesale & retail | 2018 |
| Unimed Procurement Services Limited | Wholesale & retail | 2018 |
| Union Brooks Ltd | Wholesale & retail | 2025 |
| Union Consulting Partners Uncopa UK Ltd | Wholesale & retail | 2020 |
| Union Naturelle Ltd | Wholesale & retail | 2020 |
| Union Pensions Trustees (London) Limited | Professional & scientific | 1983 |
| Union.Leicester Ltd | Professional & scientific | 2025 |
| Unipad Ltd | Real estate | 2010 |
| Unipharm Leicester Ltd | Wholesale & retail | 2023 |
| Unipow Property Limited | Real estate | 2025 |
| Uniq Style Ltd | Manufacturing | 2026 |
| Uniqminds Ltd | Education | 2023 |
| Uniqon Consulting Limited | Information & communication | 2008 |
| Unique 1A Limited | Wholesale & retail | 2023 |
| Unique Authentic Limited | Wholesale & retail | 2025 |
| Unique Choice Kitchens & Bedrooms Ltd | Manufacturing | 2019 |
| Unique Computers (LE) Ltd | Information & communication | 2011 |
| Unique Constructions (Leic) Ltd | Construction | 2024 |
| Unique Distributors Limited | Wholesale & retail | 2012 |
| Unique Financial Investments Limited | Professional & scientific | 2007 |
| Unique Fire Protection Limited | Administrative & support | 2011 |
| Unique Flowers & Photography Ltd | Wholesale & retail | 2023 |
| Unique Gems Limited | Professional & scientific | 2016 |
| Unique Group Limited | Financial services | 2015 |
| Unique Holding Services Limited | Hospitality | 2025 |
| Unique Home Solutions Limited | Construction | 2017 |
| Unique Indian Foods Limited | Hospitality | 2025 |
| Unique Interiors Leic Ltd | Manufacturing | 2020 |
| Unique Joinery Solutions Limited | Manufacturing | 2013 |
| Unique Kids Wear Limited | Wholesale & retail | 2021 |
| Unique Motorhouse Ltd | Wholesale & retail | 2018 |
| Unique Product Sales Ltd | Wholesale & retail | 2024 |
| Unique Retail Services Ltd | Wholesale & retail | 2019 |
| Unique UK Investments Limited | Financial services | 2015 |
| Unique Window Systems Holdings Ltd | Financial services | 2025 |