| Javian NO.2 Limited | Construction | 2022 |
| Jaview Limited | Wholesale & retail | 2024 |
| JAW Innovation Group Limited | Information & communication | 2024 |
| JAW Retail N.I. Limited | Wholesale & retail | 2022 |
| Jawa Pro Ltd | Wholesale & retail | 2025 |
| Jawbox Spirits Company Ltd | Extraterritorial | 2014 |
| Jawo Health Ltd | Hospitality | 2025 |
| JAX Sports Group Ltd | Professional & scientific | 2024 |
| JAY Hewitt Hair Ltd | Other services | 2025 |
| JAY T Medical Limited | Health & social care | 2024 |
| JAY Three Developments Ltd | Real estate | 2004 |
| JAYDEN3 Ltd | Wholesale & retail | 2023 |
| Jays Brow Bar Central Belfast Limited | Other services | 2014 |
| Jays Brow Bar Newry Limited | Other services | 2014 |
| Jazz Consulting Ltd | Information & communication | 2025 |
| JB BDS Ltd | Health & social care | 2019 |
| JB Cabling Solutions Ltd | Information & communication | 2021 |
| JB Chauffeurs (IRL) Ltd | Transport & logistics | 2026 |
| JB Chemicals Ltd | Wholesale & retail | 2025 |
| JB Components (NI) Limited | Administrative & support | 2005 |
| JB Sign Services Ltd | Manufacturing | 2009 |
| JBA Design Consultancy Ltd. | Professional & scientific | 2016 |
| JBB Belfast Limited | Hospitality | 2024 |
| Jbdcam Limited | Financial services | 2021 |
| JBG Groundworks Ltd | Construction | 2023 |
| Jbni Limited | Hospitality | 2018 |
| JC Finance Broker Ltd | Financial services | 2016 |
| JC Fitting Ltd | Manufacturing | 2019 |
| JC Imaging Limited | Health & social care | 2022 |
| JC Weighbridge Ltd | Real estate | 2024 |
| JC1 Ltd | Information & communication | 2024 |
| JCA 67 Ltd | Health & social care | 2024 |
| JCA Eighty Three Limited | Other services | 2020 |
| JCA Maintenance and Repair Ltd | Manufacturing | 2015 |
| JCA Ninety Eight Limited | Construction | 2021 |
| JCA Ninety Two Limited | Other services | 2021 |
| JCA One Hundred and Eleven Limited | Financial services | 2022 |
| JCA One Hundred and Fifty One Limited | Extraterritorial | 2026 |
| JCA One Hundred and Fourteen Limited | Other services | 2022 |
| JCA One Hundred and Nine Limited | Financial services | 2022 |
| JCA One Hundred and Nineteen Limited | Administrative & support | 2023 |
| JCA One Hundred and Thirty Nine Limited | Extraterritorial | 2024 |
| JCA One Hundred and Thirty One Limited | Extraterritorial | 2024 |
| JCA One Hundred and Thirty SIX Limited | Health & social care | 2024 |
| JCA One Hundred and Three Limited | Real estate | 2021 |
| JCA One Hundred and Twelve Limited | Real estate | 2022 |
| JCA One Hundred and Twenty Four Limited | Extraterritorial | 2023 |
| JCA One Hundred and Twenty One Limited | Administrative & support | 2023 |
| JCA Thirtythree Limited | Real estate | 2013 |
| JCF Media Ltd | Professional & scientific | 2024 |
| Jchukz Properties Ltd | Real estate | 2015 |
| Jcomms 1976 Ltd | Information & communication | 2001 |
| JCP Consulting Limited | Professional & scientific | 2001 |
| JCR Advisory Limited | Professional & scientific | 2024 |
| JCS Ents Ltd | Arts & recreation | 2025 |
| JCS Flooring Limited | Construction | 2014 |
| JD Auto Group Ltd | Wholesale & retail | 2026 |
| JD Farms Ltd | Agriculture & fishing | 2009 |
| JD Kelly Limited | Hospitality | 2022 |
| JD Real Estate Holdings Ltd | Real estate | 2025 |
| JD Tattoos Ltd | Arts & recreation | 2018 |
| JD23 HC Limited | Health & social care | 2023 |
| JDI Direct Ltd | Construction | 2018 |
| Jdmc 2020 Limited | Professional & scientific | 2021 |
| JDP Retail Limited | Wholesale & retail | 2019 |
| JDR Commercial Solutions NI Limited | Transport & logistics | 2018 |
| Jdrrsq Ltd | Wholesale & retail | 2024 |
| JDT International Ltd | Transport & logistics | 2019 |
| JEA Digital Trding Ltd | Wholesale & retail | 2026 |
| Jean Mckee Ltd | Wholesale & retail | 2023 |
| Jean Millar & Company | Wholesale & retail | 1950 |
| Jean Millar NI Ltd | Wholesale & retail | 2010 |
| Jeanro Computing Ltd | Information & communication | 1999 |
| Jebin Global Limited | Health & social care | 2025 |
| Jeeps Limited | Real estate | 2007 |
| Jeff Hayes Ltd | Wholesale & retail | 2025 |
| Jeffers Bakery Ltd | Hospitality | 2015 |
| Jeffers Holdings Ltd | Financial services | 2018 |
| Jeffrey Wray Ltd | Wholesale & retail | 2025 |
| Jefreight Ltd | Transport & logistics | 2022 |
| Jegs-Din Limited | Real estate | 1998 |
| Jelly Mall Limited | Wholesale & retail | 2025 |
| Jellybean Cafe Ltd | Hospitality | 2011 |
| JELLYBEAN7 Ltd | Wholesale & retail | 2026 |
| JEM P Jams Ltd | Wholesale & retail | 2022 |
| Jem's Catering Limited | Hospitality | 2026 |
| Jemni Group Ltd | Financial services | 2013 |
| Jemrob Developments LLP | | 2021 |
| Jemy Developments Ltd | Construction | 2019 |
| Jemy Rentals Ltd | Real estate | 2023 |
| Jena Zhan Limited | Wholesale & retail | 2024 |
| Jench Ltd | Real estate | 2025 |
| Jenie Doer Ltd | Wholesale & retail | 2024 |
| Jenkins NO 2 Ltd | Transport & logistics | 1982 |
| Jenkins Shipping Company Limited | Transport & logistics | 2003 |
| Jenkins Shipping Transport Limited | Transport & logistics | 2008 |
| Jenkins Stevedoring Company Limited | Transport & logistics | 1996 |
| Jenkinson Agencies (NI) Limited | Professional & scientific | 1981 |
| Jennet Allamyradova Limited | Wholesale & retail | 2024 |
| Jennifer Blair Ltd | Wholesale & retail | 2025 |