| JKT Dental Ltd | Health & social care | 2026 |
| JL Restaurant Group Ltd | Hospitality | 2021 |
| JLC Flooring Ltd | Construction | 2020 |
| JLD Retail Limited | Other services | 2018 |
| JLF Property Ltd | Real estate | 2014 |
| JLG Supplies Limited | Wholesale & retail | 2020 |
| JLM Roofing and Paving Ltd | Construction | 2025 |
| JLP Enterprises Ltd | Hospitality | 2016 |
| Jlpt Perfectly YOU Ltd | Health & social care | 2024 |
| JM Adams Agencies Ltd | Wholesale & retail | 2016 |
| JM Billposting Ltd | Other services | 2018 |
| JM Engineering (2026) Ltd | Construction | 2026 |
| JM Lifting Services Belfast Ltd | Professional & scientific | 2026 |
| JM Maggies Limited | Hospitality | 2015 |
| JM Protection N.Ireland Ltd | Professional & scientific | 2023 |
| JMA Clinical Consulting Ltd | Health & social care | 2024 |
| Jmac Investments Ltd | Real estate | 2006 |
| Jmax Property Ltd | Real estate | 2024 |
| JMC Invts Ltd | Real estate | 2010 |
| JMC Losjarales Limited | Information & communication | 2018 |
| JMC Micro Tech Ltd | Professional & scientific | 2016 |
| JMC Property Developments Limited | Construction | 1995 |
| JMC Sport UK Limited | Professional & scientific | 2022 |
| Jmcf Advisory Limited | Administrative & support | 2024 |
| Jmcg Consultancy Ltd | Administrative & support | 2025 |
| Jmcg Holdings Limited | Real estate | 2022 |
| Jmcg Property Services Limited | Real estate | 2018 |
| Jmck Services Ltd | Arts & recreation | 2024 |
| Jmcv Radiology Ltd | Health & social care | 2025 |
| JMD Motors Ltd | Wholesale & retail | 2015 |
| JMD Real Estate Consulting Ltd | Real estate | 2024 |
| Jmdm Properties LLP | | 2013 |
| JMG Contracts Ltd | Construction | 2016 |
| JMG Developments N.I. Ltd | Construction | 2002 |
| JMG Flooring Limited | Construction | 2024 |
| JMK Commerce Ltd | Wholesale & retail | 2023 |
| JMK Consultancy Limited | Professional & scientific | 2021 |
| JMK Recycling Limited | Manufacturing | 2020 |
| JMK Solicitors (NI) Ltd | Professional & scientific | 2010 |
| JML Construction Group Holdings Ltd | Professional & scientific | 2022 |
| JML Construction Group Limited | Construction | 2020 |
| JML Contract Services Limited | Construction | 2015 |
| JML Homes Limited | Construction | 2016 |
| JML Property Investors Limited | Real estate | 2025 |
| JMM Aerospace Ltd | Manufacturing | 2015 |
| JMM Medical Services Ltd | Health & social care | 2014 |
| JMP Media Ltd | Information & communication | 2023 |
| JMR Hair Ltd | Other services | 2026 |
| Jmrb Ltd | Real estate | 2022 |
| JMS Joinery and Building Works Ltd | Construction | 2011 |
| JMS Joinery Holdings Ltd | Financial services | 2025 |
| JMS Pharma Ltd | Health & social care | 2011 |
| Jmsd Ltd | Health & social care | 2025 |
| JMW Aerospace Consulting Ltd | Professional & scientific | 2022 |
| JN - Visual Effects Limited | Arts & recreation | 2019 |
| JN Contracts Belfast Ltd | Wholesale & retail | 2022 |
| JNB Solutions Limited | Real estate | 2023 |
| JNC Funding Limited | Professional & scientific | 2016 |
| JND Trading Ltd | Wholesale & retail | 2025 |
| Jnekhh OU Ltd | Wholesale & retail | 2025 |
| JNP Architects Limited | Professional & scientific | 2022 |
| JNP Group Consulting Engineers Belfast Limited | Professional & scientific | 2024 |
| JO Andrews Interiors and Furniture Design Ltd | Manufacturing | 2016 |
| Joanne Irwin Ltd | Wholesale & retail | 2025 |
| Joanne Mccall Ltd | Wholesale & retail | 2024 |
| Jodio Limited | Real estate | 2025 |
| Jodni Limited | Information & communication | 2016 |
| JOE Brolly Holdings Ltd | Financial services | 2021 |
| JOE Gallagher Entertainments Intl Ltd | Arts & recreation | 2017 |
| JOE O'Sullivan Oncology Limited | Health & social care | 2012 |
| Joe's Barbers Ltd | Other services | 2013 |
| Joel ANN Ball Limited | Wholesale & retail | 2024 |
| Joel Limited | Real estate | 1985 |
| Jofun Ltd | Wholesale & retail | 2024 |
| Jogaad Ventures Limited | Hospitality | 2025 |
| Joghurt Limited | Manufacturing | 2021 |
| Johan Lima Developments Ltd | Construction | 2021 |
| John Bennett Contracting Limited | Construction | 2017 |
| John Brown University Northern Ireland | Education | 2013 |
| John Brydon Radcliffe Ltd | Wholesale & retail | 2022 |
| John C.Brow, Limited | Manufacturing | 1943 |
| John D. Keane Limited | Professional & scientific | 2007 |
| John Dynes & SON Ltd | Construction | 2015 |
| John Frazer (Apparel) | Real estate | 1975 |
| John Frazer (Properties) Limited | Real estate | 1978 |
| John G. Fleming Limited | Wholesale & retail | 1997 |
| John H. Lunn (Jewellers), Limited | Wholesale & retail | 1954 |
| John Henry Taylor Ltd | Wholesale & retail | 2025 |
| John Hewitt Society -the | Arts & recreation | 2001 |
| John Hunter Glazing Limited | Construction | 2011 |
| John J Rice & Co Ltd | Professional & scientific | 2010 |
| John J. Doyle Limited | Construction | 1964 |
| John Joseph Mcdaniel Limited | Extraterritorial | 2025 |
| John Keers and Sons, Limited | Professional & scientific | 1958 |
| John Kelly Limited | Professional & scientific | 1911 |
| John Laverty Limited | Manufacturing | 2021 |
| John Lavery Ltd | Manufacturing | 2024 |
| John Luke Limited | Wholesale & retail | 2022 |
| John Mackin Ltd | Wholesale & retail | 2025 |
| John Mcdowell (Donegall Road) Limited | Health & social care | 2021 |