| Tumble N FUN NI Limited | Administrative & support | 2021 |
| Tumilty's Farm Ltd | Agriculture & fishing | 2025 |
| Turley Bros UK Ltd | Transport & logistics | 2020 |
| Turley Property Consultants Limited | Professional & scientific | 2018 |
| Turlough O'Donnell | Health & social care | 2012 |
| Turlough O'Donnell Orthopaedics Limited | Health & social care | 2012 |
| Turmore Capital Limited | Professional & scientific | 2014 |
| Turmore Limited | Construction | 2021 |
| Turnavall Farm Meats Ltd | Extraterritorial | 2005 |
| Tusker Contracts NI Limited | Construction | 2009 |
| Tvpm Ltd | Real estate | 2019 |
| TW Hill Joinery Limited | Construction | 2025 |
| TW Medical Limited | Health & social care | 2011 |
| Twin Peak Construction Ltd | Construction | 2016 |
| Two Guys Coffee Ltd | Manufacturing | 2024 |
| Two Spires Technology Ltd | Financial services | 2023 |
| Tynan Enterprises Ltd | Hospitality | 1993 |
| Tyncho UK Limited | Wholesale & retail | 2021 |
| Tyre Distributors Limited | Wholesale & retail | 2019 |
| Tyrebay Belfast Limited | Wholesale & retail | 2010 |
| Tyroler Ltd | Wholesale & retail | 2024 |
| U.S.P.C.A. Trading Limited | Extraterritorial | 1991 |
| U3 Solutions Limited | Information & communication | 2016 |
| Ubhall Limited | Information & communication | 2019 |
| UC Finance LP | | 2016 |
| Ucam Plant Hire Limited | Construction | 2015 |
| Ucandoo Ltd | Information & communication | 2011 |
| UEW DPF Refurbishment Ltd | Wholesale & retail | 2020 |
| UGP Newry HC Limited | Financial services | 2023 |
| UGP Newry Limited | Real estate | 2023 |
| UGP Newry Shopping Centre Ltd | Real estate | 2026 |
| UGP Retail Services Limited | Wholesale & retail | 2024 |
| UHP Services Limited | Professional & scientific | 2019 |
| UK Autos Enterprise Ltd | Wholesale & retail | 2025 |
| Ullord Ltd | Extraterritorial | 2021 |
| Ulster Bullion Embroidery Co. Limited - the | Manufacturing | 2001 |
| Ulster Catering Ltd | Hospitality | 2026 |
| Ulster Commercials Limited | Manufacturing | 2021 |
| Ulster Society for Prevention of Cruelty to Animals - the | Wholesale & retail | 1925 |
| Ulstermux Ltd | Information & communication | 2022 |
| Ultimate Battle Royale Ltd | Arts & recreation | 2025 |
| Ultimate Interiors NI Ltd | Professional & scientific | 2024 |
| Ultimate Pool All-Ireland Ltd | Arts & recreation | 2026 |
| Ultimate Training Ltd | Administrative & support | 2021 |
| Ultimo Trans L.P. | | 2017 |
| Ultra Renewables Ltd | Construction | 2023 |
| Umricam Services Limited | Manufacturing | 2018 |
| UMS Trade Ltd | Wholesale & retail | 2024 |
| UNA Cunningham Ltd | Other services | 2017 |
| UNA Kadams PTE Ltd | Wholesale & retail | 2023 |
| Underwaterpistol Ltd | Information & communication | 2012 |
| Uneedpower.Com Limited | Manufacturing | 2025 |
| Uniflex Overseas L.P. | | 2015 |
| Unifront Sales L.P. | | 2017 |
| Unilin Flooring UK Limited | Wholesale & retail | 1991 |
| Unique Holding Ltd | Hospitality | 2009 |
| Unique Print Ltd | Wholesale & retail | 2021 |
| Unislim Clubs Limited | Administrative & support | 1972 |
| Unislim Gorge US Ltd | Administrative & support | 2022 |
| Unit 24 Pods Ltd | Arts & recreation | 2026 |
| Unity Wedding Cars Ltd | Manufacturing | 2009 |
| Universal Stud Ltd | Agriculture & fishing | 2020 |
| Unreal (N.I.) Ltd | Hospitality | 2022 |
| UP Above Consulting Ltd | Information & communication | 2026 |
| UP N Down Projects Ltd | Information & communication | 2023 |
| Upickkilkeel Ltd | Hospitality | 2022 |
| Uplevel Consulting Ltd | Information & communication | 2021 |
| Uptime Labs IT NI Ltd | Information & communication | 2023 |
| Urban Biomass Ltd | Manufacturing | 2014 |
| Urban Contracts IRE Limited | Construction | 2021 |
| Urban Renew (NI) Limited | Administrative & support | 2016 |
| Urker Ltd | Transport & logistics | 2019 |
| V H Electrics Ltd | Manufacturing | 2005 |
| V Mesh Fencing Limited | Construction | 2014 |
| V.M. Carpentry Services Limited | Construction | 2002 |
| Vac-Excavation Northern Ireland Ltd | Construction | 2025 |
| Vadio Limited | Professional & scientific | 2014 |
| Valhallas Silver Ltd | Manufacturing | 2012 |
| Vallely Electrical Ltd | Construction | 2019 |
| Valley Filters UK Limited | Water & waste | 2022 |
| Valley View Contracts Limited | Construction | 2025 |
| Vallymore Ltd | Construction | 2017 |
| Vallymore Rentals Ltd | Real estate | 2020 |
| Valter Corp. LP | | 2015 |
| Value Bazaar Newry Ltd | Wholesale & retail | 2026 |
| Value Foam Ltd | Construction | 2020 |
| Vanra Group Limited | Construction | 2025 |
| Vantos Data Ltd | Professional & scientific | 2025 |
| Vape Garden Distro Ltd | Wholesale & retail | 2025 |
| Varpa C.A. L.P. | | 2017 |
| Vava Influence Ltd | Professional & scientific | 2020 |
| Vector Manufacturing Ltd | Manufacturing | 2018 |
| Vectorlogic Ltd | Information & communication | 2021 |
| Vega Studio UK Ltd | Other services | 2014 |
| Vegastar Trade L.P. | | 2017 |
| Vehicle Sourcing NI Ltd | Extraterritorial | 2023 |
| Vela Microboards NI Limited | Health & social care | 2004 |
| VEN Electrical Ltd | Construction | 2026 |
| Vent Communications LP | | 2018 |
| Ventley Projects L.P. | | 2017 |