| Kane of Comber Limited | Extraterritorial | 1970 |
| Kaner Bros Ltd | Manufacturing | 2025 |
| Kanesbrook Properties Ltd | Construction | 2005 |
| Kanesystems Limited | Information & communication | 2025 |
| Kang Jian Ltd | Health & social care | 2012 |
| Kang Management Limited | Real estate | 2014 |
| Kang Sling Limited | Wholesale & retail | 2023 |
| Kanopi Ltd | Information & communication | 2021 |
| Kansas Developments Ltd | Real estate | 2024 |
| Kanto Asian Fusion Ltd | Hospitality | 2022 |
| Kanvass Tech Ltd | Information & communication | 2024 |
| Kapell Bernd Ltd | Wholesale & retail | 2023 |
| Kapp Merchants Limited | Real estate | 1988 |
| Kappa Engineering Ltd | Manufacturing | 2026 |
| Kapricorn Ltd | Wholesale & retail | 2024 |
| Kapwa Group Limited | Wholesale & retail | 2024 |
| KAR Foods Ltd | Wholesale & retail | 2024 |
| Karami Limited | Professional & scientific | 2021 |
| Karan Anand Ltd | Information & communication | 2024 |
| Karb AI Limited | Information & communication | 2025 |
| Kardel Limited | Professional & scientific | 2024 |
| Karen Donaghy Ltd | Hospitality | 2016 |
| Karen Goodin Limited | Wholesale & retail | 2025 |
| Karen Mcshane Ltd | Professional & scientific | 2024 |
| Karkraft (N.I.) Limited | Administrative & support | 1984 |
| Karl Baldwin Ltd | Wholesale & retail | 2024 |
| Karl Johnston Ltd | Wholesale & retail | 2023 |
| Karma Services (NI) Limited | Other services | 2018 |
| Karma Wholesale International Limited | Wholesale & retail | 2011 |
| Karmic Relief Ltd | Health & social care | 2023 |
| Karp Ltd | Manufacturing | 2025 |
| Karr Site Services Ltd | Construction | 2018 |
| Karrakk LP | | 2018 |
| Karri Kitchen Ltd | Wholesale & retail | 2019 |
| Karror Limited | Wholesale & retail | 2025 |
| Kash Commerce Ltd | Wholesale & retail | 2023 |
| Kashif Prime Ltd | Wholesale & retail | 2025 |
| Kashmir Belfast Ltd | Real estate | 2020 |
| Kasiana Ltd | Wholesale & retail | 2025 |
| Kasinok Limited | Wholesale & retail | 2025 |
| Kasteel Protection Ltd | Administrative & support | 2024 |
| KAT Lkiu Ltd | Wholesale & retail | 2024 |
| Kataar Investments Ltd | Financial services | 2022 |
| Katco Ltd | Wholesale & retail | 2023 |
| Kate Anna Kelly Ltd | Wholesale & retail | 2026 |
| Katecam Ltd | Wholesale & retail | 2024 |
| Kathmandu Property Limited | Real estate | 2022 |
| Kathmandu Restaurant Ltd | Hospitality | 2017 |
| Kathrina Fashions (Marketing) Limited | Manufacturing | 1999 |
| Kathryn Callaghan Fine Art Limited | Wholesale & retail | 2015 |
| Kathury Limited | Wholesale & retail | 2023 |
| Kathy Brennan PMU Academy Ltd | Other services | 2023 |
| Kathy Developments Limited | Construction | 2015 |
| Katie & Joseph's Pizzeria Ltd | Hospitality | 2024 |
| Katofizzy Ltd | Energy | 2026 |
| KAU Shen Industrial Co Ltd | Wholesale & retail | 2025 |
| Kauffee Ltd | Wholesale & retail | 2019 |
| Kavaclan Care Ltd | Health & social care | 2021 |
| Kaveesha Limited | Professional & scientific | 2012 |
| Kawe Investments Limited | Real estate | 2019 |
| KAY Devlin Ltd | Manufacturing | 2021 |
| Kaya Ballyhack Ltd | Hospitality | 2025 |
| Kayah Limited | Wholesale & retail | 2017 |
| Kayfoam Woolfson (Belfast) Limited | Manufacturing | 1968 |
| Kayrath Investments Limited | Hospitality | 1978 |
| Kayy Superstores Limited | Hospitality | 2026 |
| Kazeho Limited | Wholesale & retail | 2024 |
| Kazmc Ltd | Financial services | 2026 |
| KB & NB Holdings Limited | Financial services | 2025 |
| KB Developments Limited | Financial services | 2019 |
| KB Dynamites Ltd | Wholesale & retail | 2025 |
| KB Property Belfast Ltd | Real estate | 2023 |
| KBA Motors Ltd | Wholesale & retail | 2025 |
| KBB Property Solutions Ltd | Real estate | 2025 |
| KBB Trade Limited | Administrative & support | 2025 |
| KBM Decorators Ltd | Construction | 2021 |
| KBS (NI) Limited | Wholesale & retail | 2012 |
| KBS Computer Supplies Ltd | Manufacturing | 1999 |
| KBS IT & Office Solutions Ltd | Information & communication | 2025 |
| Kbshdjufa Ltd | Wholesale & retail | 2024 |
| KC 2021 GG Limited | Construction | 2021 |
| KC 2021 RT Ltd | Construction | 2021 |
| KC Appointments (NI) | Professional & scientific | 2005 |
| KCG Group Consulting Ltd | Professional & scientific | 2016 |
| KCM IT Services Ltd | Information & communication | 2022 |
| KCP Contracts Limited | Construction | 2026 |
| Kcpg Limited | Wholesale & retail | 2011 |
| KCR Holdings Ltd | Real estate | 2012 |
| KCS (NI) Limited | Professional & scientific | 2011 |
| KD Access and Coatings Ltd | Construction | 2018 |
| KD OFF Sales Ltd | Wholesale & retail | 2020 |
| KD Properties 2022 Limited | Real estate | 2022 |
| KDL Management Limited | Professional & scientific | 2003 |
| KE Consultants Ltd | Administrative & support | 2022 |
| KE Consumer Ltd | Wholesale & retail | 2024 |
| KEA Real Estate Limited | Professional & scientific | 2023 |
| Keaney Medical Limited | Other services | 1999 |
| Kearney Sefton Solicitors Limited | Professional & scientific | 2015 |
| Kearney's Yard Ltd | Real estate | 2020 |
| Kebab House Andersonstown Ltd | Hospitality | 2023 |