| Kitchenmaster Group Limited | Manufacturing | 2018 |
| Kitchenscomplete Ltd | Manufacturing | 2020 |
| Kitday Limited | Information & communication | 2026 |
| Kitesurf Warehouse Limited | Wholesale & retail | 2011 |
| Kith & KIN Financial Solutions C.I.C. | Professional & scientific | 2015 |
| Kitking (NI) Limited | Wholesale & retail | 2013 |
| Kits IT Limited | Information & communication | 2015 |
| Kitsch Sisters CIC | Hospitality | 2024 |
| Kitsilano Developments Ltd | Financial services | 2021 |
| Kitson Residential Ltd | Real estate | 2017 |
| Kiwi Property Management Ltd | Real estate | 2024 |
| Kiwind Ltd | Professional & scientific | 2017 |
| Kiyu Trading Limited | Professional & scientific | 2024 |
| KJC Estates Ltd | Real estate | 2010 |
| KJF Trading Ltd | Financial services | 2026 |
| KJM Catering Ltd | Hospitality | 2025 |
| KJM Cleaning Services Ltd | Administrative & support | 2026 |
| Kjms Imaging Ltd | Health & social care | 2019 |
| KJW Electrical Engineering (NI) Ltd | Information & communication | 2024 |
| KK Architectural Services Ltd | Professional & scientific | 2023 |
| KKA Investments Limited | Financial services | 2018 |
| Kkeefo Supply Chain Ltd | Wholesale & retail | 2024 |
| KKM Investments Limited | Hospitality | 2011 |
| Kkrecruit Limited | Administrative & support | 2025 |
| Klas Therapeutics Limited | Professional & scientific | 2021 |
| Klaus Berghaus Limited | Wholesale & retail | 2023 |
| Klemt Mario Ltd | Wholesale & retail | 2023 |
| Klientflow Limited | Administrative & support | 2025 |
| Kliqxe Technology Ltd | Information & communication | 2021 |
| KLJ Properties Limited | Real estate | 2010 |
| KLM Engineering Advisers Limited | Professional & scientific | 2021 |
| Klondyke 2026 Limited | Real estate | 2026 |
| Klovd Consulting Limited | Information & communication | 2024 |
| KLS Aesthetics Ltd | Health & social care | 2026 |
| KM London Ltd | Wholesale & retail | 2026 |
| KM Prestige Limited | Wholesale & retail | 2025 |
| KM Property C/O Key Lets NI Ltd | Households | 2023 |
| KM Rentals N.I Ltd | Real estate | 2024 |
| Kmac Associates Limited | Energy | 2016 |
| Kmac Drywall IE Ltd | Construction | 2019 |
| Kmac Properties (N.I.) Ltd | Real estate | 2023 |
| Kmaerospace Ltd | Manufacturing | 2019 |
| KMC Medical Ltd | Health & social care | 2021 |
| Kmdl Engineering (NI) Ltd | Construction | 2009 |
| KMG Advisory Ltd | Professional & scientific | 2026 |
| KML Plant Hire Limited | Construction | 2015 |
| KMM Connect Ltd | Wholesale & retail | 2025 |
| Kmmma Ltd | Arts & recreation | 2025 |
| Kmpc Estates Ltd | Real estate | 2010 |
| Kmpm Property Limited | Hospitality | 2024 |
| KMR Mechanical Ltd | Professional & scientific | 2025 |
| Kmse Estates Limited | Real estate | 2016 |
| Kmysbt Ltd | Wholesale & retail | 2024 |
| KN 03 Trading Ltd | Hospitality | 2023 |
| Kneecap 1 Films Limited | Information & communication | 2025 |
| Kneecap Films Limited | Information & communication | 2022 |
| Knight High Purity Pipework Limited | Other services | 2025 |
| Knighton Leisure (N.I.) Limited | Arts & recreation | 2022 |
| Knighton Leisure Belfast Limited | Arts & recreation | 2016 |
| Knightsbridge Clinic Ltd | Professional & scientific | 2015 |
| Knightsbridge Thirty-One Limited | Hospitality | 2015 |
| Knightsbridge Thirty-Three Limited | Households | 2016 |
| Knightsbridge Wealth Management (NI) Ltd | Financial services | 2008 |
| Knightswood Consulting Limited | Administrative & support | 2013 |
| Knlm Health Ltd | Health & social care | 2023 |
| Knob-Busters Rigging Ltd | Information & communication | 2023 |
| Knock Child Contact Centre | Health & social care | 2011 |
| Knock Golf Club Limited | Arts & recreation | 1920 |
| Knockalla Holdings Limited | Financial services | 2019 |
| Knockany Imaging Ltd | Health & social care | 2022 |
| Knockavannon Ltd | Energy | 2013 |
| Knockavoe Renewables Limited | Energy | 2016 |
| Knockbrack Ltd | Wholesale & retail | 2021 |
| Knockbreda Consulting Limited | Professional & scientific | 2011 |
| Knockburn Management Limited | Financial services | 2018 |
| Knockburn Mews Management Company Ltd | Households | 2011 |
| Knockburn Real Estate LLP | | 2010 |
| Knockdarragh (Phase 2) Property Management Ltd | Households | 2006 |
| Knockdarragh Management Company Limited | Real estate | 2015 |
| Knockdene Gate Management Company Limited | Households | 2005 |
| Knockdene Manor Limited | Households | 1999 |
| Knockfierna Properties Limited | Real estate | 2022 |
| Knockhill Ltd | Financial services | 2026 |
| Knockmoreone Limited | Real estate | 2023 |
| Knocknagore Limited | Real estate | 2024 |
| Knocknaraven Limited | Transport & logistics | 2013 |
| Knockninny Developments Ltd | | 2006 |
| Knockraine Farms Limited | Agriculture & fishing | 1996 |
| Knocksallagh Management Company (NO 2) Limited | Real estate | 2023 |
| Knocksallagh Management Ltd | Households | 2013 |
| Knockvale Grove Management Limited | Households | 2009 |
| Knockvale Park Management Company Limited | Households | 2002 |
| Knowleds Ltd | Information & communication | 2021 |
| Knowridge Limited | Information & communication | 2025 |
| Knst Coffee Ltd | Hospitality | 2025 |
| KNX Consulting Ltd | Professional & scientific | 2025 |
| Ko'Drilla Ltd | Information & communication | 2025 |
| Koad Clothing Ltd | Wholesale & retail | 2024 |
| Kobault Limited | Information & communication | 2019 |
| Kodeela Technology Co Limited | Wholesale & retail | 2026 |