| Ulster Friends Trustees, Limited | Other services | 1937 |
| Ulster Weavers Home Limited | Manufacturing | 2010 |
| Ultrazan Ltd | Wholesale & retail | 2026 |
| Un/Altered Ltd | Wholesale & retail | 2021 |
| Uni-Trunk Group Holdings Limited | Financial services | 2020 |
| Uni-Trunk Holdings Limited | Professional & scientific | 2013 |
| Uni-Trunk Limited | Manufacturing | 1961 |
| Unicor Ventures Limited | Health & social care | 2017 |
| Unicorn (Northern Ireland) Limited | Extraterritorial | 2010 |
| Unicorn Containers Limited | Manufacturing | 1995 |
| Unicorn Flooring Limited | Manufacturing | 1993 |
| Unicorn Group Holdings Limited | Financial services | 2019 |
| Unicorn Group Partnership CIC | Public administration | 2024 |
| Unicorn Hygienics Limited | Manufacturing | 2006 |
| Unicorn Manufacturing Limited | Extraterritorial | 2005 |
| Unicorn Sales and Marketing Limited | Extraterritorial | 1966 |
| Unicorn Self Serve Limited | Extraterritorial | 1915 |
| Unicorn Urban Limited | Extraterritorial | 2009 |
| Unified Business Group LLP | | 2017 |
| Unitek Timber Framed Systems Limited | Construction | 2014 |
| Unitrunk Cable Trunking Systems Limited | Manufacturing | 1976 |
| Unity IT Ltd | Information & communication | 2003 |
| UPH - United Property Holdings Limited | Real estate | 2025 |
| Uplis Road Blow DRY Bar Limited | Other services | 2010 |
| Upskillni Limited | Education | 2024 |
| Upublic Ltd | Professional & scientific | 2026 |
| Upwind Solutions Ltd | Professional & scientific | 2006 |
| Uran Medical Services Ltd | Health & social care | 2019 |
| Urban Cycle Technologies Ltd | Wholesale & retail | 2024 |
| Urban Entertainment Ltd | Hospitality | 2023 |
| Urban Fire (2021) Ltd | Hospitality | 2021 |
| Urban Kitchens KDC Ltd | Manufacturing | 2022 |
| Urrús Consultancy Limited | Professional & scientific | 2020 |
| USA Nails Lisburn Ltd | Other services | 2025 |
| Usiome Limited | Other services | 2020 |
| Utility Solutions (Landlines to Mobiles) Limited | Professional & scientific | 2023 |
| Utility Solutions N.I. Limited | Information & communication | 2015 |
| Van About Town (2023) Ltd | Transport & logistics | 2023 |
| Vanden Recycling Limited | Wholesale & retail | 2012 |
| Varsity Estates Ltd. | Real estate | 1990 |
| VAULT27 Ltd | Information & communication | 2024 |
| VDL Construction Management Limited | Construction | 2010 |
| Velasseryil Imports and Distribution Ltd | Wholesale & retail | 2019 |
| Velora Lane Ltd | Wholesale & retail | 2026 |
| Vending and Refrigeration Services Ltd | Manufacturing | 2006 |
| Venture Air Ltd | Wholesale & retail | 2025 |
| Veri-T Limited | Information & communication | 2025 |
| Vertex Management LP | | 2025 |
| Veterinary Surgeons Supply Company Limited | Wholesale & retail | 1956 |
| Vetzone NI Limited | Professional & scientific | 2025 |
| Vgen Foods Ltd | Manufacturing | 2026 |
| Vhsni Ltd | Wholesale & retail | 2019 |
| Vibe Franchising International LP | | 2025 |
| Victoc Technology Co Limited | Wholesale & retail | 2026 |
| Victor Capital Holdings Limited | Real estate | 2021 |
| Viewpoint Developments Limited | Construction | 2013 |
| Viewpoint Leisure Ltd | Other services | 2006 |
| Vijayshobha Ltd | Transport & logistics | 2026 |
| Vilnuis Ltd | Hospitality | 2026 |
| Vine Group Limited | Hospitality | 2025 |
| Vinyl Logic Limited | Wholesale & retail | 2019 |
| Viridismaris Ltd | Wholesale & retail | 2025 |
| Virtual Eco-Advisors Limited | Professional & scientific | 2020 |
| Virtual Property Partners Limited | Professional & scientific | 2021 |
| Vision Fabrications Limited | Construction | 2017 |
| Vision Sales Direct Limited | Wholesale & retail | 2006 |
| Vison Limited | Professional & scientific | 2013 |
| Visual Aesthetics Limited | Arts & recreation | 2018 |
| VK Competitions Ltd | Information & communication | 2023 |
| Voduz Ltd | Wholesale & retail | 2019 |
| Vojo IP Limited | Information & communication | 2017 |
| Vojo Media Limited | Information & communication | 2016 |
| Voltohm Ltd | Construction | 2019 |
| Vornbrook Management Limited | Professional & scientific | 2017 |
| Vspine Ltd | Health & social care | 2011 |
| Vssco Veterinary Practice Ltd | Professional & scientific | 2021 |
| Vyrtuo Solutions Ltd | Information & communication | 2024 |
| Vysakh Mohan Photography Limited | Professional & scientific | 2025 |
| W & S Mcgp Ltd | Hospitality | 2025 |
| W F Lemon & Co Ltd | Professional & scientific | 2011 |
| W J Law Holdings Ltd | Real estate | 1999 |
| W Polly Construction Limited | Construction | 2013 |
| W.C. Guthrie Limited | Manufacturing | 1972 |
| W.F.I. Limited | Hospitality | 1989 |
| W.G. Maginess & SON Ltd | Professional & scientific | 2013 |
| Wade Electrical Services Ltd | Construction | 2018 |
| Wag'N'Stay Ltd | Other services | 2018 |
| Waggy Races LLP | | 2014 |
| Waka Express Lisburn Ltd | Hospitality | 2025 |
| Walk 'N' Dogs Ltd | Other services | 2016 |
| Walker Boxing Limited | Arts & recreation | 2021 |
| Walker Fuels Ltd | Wholesale & retail | 2024 |
| Wall Designni Ltd | Manufacturing | 2025 |
| Wallace Contracts (NI) Limited | Construction | 2007 |
| Walsh Entertainment Ltd | Arts & recreation | 2018 |
| Walsh Music Publishing Limited | Information & communication | 2024 |
| Walsh Residential Group Ltd | Construction | 2026 |
| Walsh Scaffolding Limited | Construction | 2007 |
| Walsin Group Limited | Financial services | 2017 |
| Walsin Limited | Construction | 1994 |