| KJP Home Improvements Ltd | Construction | 2019 |
| KJS Groundworks Newforest Limited | Construction | 2025 |
| KJS Mental Health Limited | Health & social care | 2025 |
| KJT Plumbing Services Limited | Construction | 2026 |
| KJV Group Limited | Construction | 2020 |
| KJW Groundworks Ltd | Construction | 2016 |
| KK & AC Limited | Hospitality | 2021 |
| KK Alma Properties Limited | Real estate | 2016 |
| KK Auto Services Ltd | Wholesale & retail | 2019 |
| KK Winchester Limited | Administrative & support | 2004 |
| KKB Electrical Ltd | Construction | 2022 |
| KKD Scaffolding Limited | Construction | 2024 |
| KKR Letting and Development Ltd | Real estate | 2020 |
| Kktk 2 Limited | Hospitality | 2001 |
| KL Health Care Ltd | Wholesale & retail | 2023 |
| KL Multi Builds Limited | Construction | 2025 |
| Klaass Ltd | Education | 2014 |
| KLB Dynamics Ltd | Real estate | 2024 |
| KLC Counselling Ltd | Health & social care | 2021 |
| KLG Property Investments Ltd | Real estate | 2022 |
| Klic-Key Ltd | Manufacturing | 2021 |
| KLM Properties Ltd | Real estate | 2026 |
| KLP Consultants Limited | Other services | 2013 |
| Klpf Properties Limited | Real estate | 2023 |
| Klutzy Dragon Ltd | Arts & recreation | 2026 |
| KM Crafted Interiors Ltd | Construction | 2019 |
| KM Elite Cleaning Services Ltd | Administrative & support | 2022 |
| KM Projects Ltd | Real estate | 2026 |
| KMA Consultancy Limited | Information & communication | 2017 |
| KMA Tailored Solutions Ltd | Administrative & support | 2015 |
| Kmari and Co Ltd | Wholesale & retail | 2026 |
| Kmarley Ltd | Health & social care | 2014 |
| Kmax Performance Ltd | Wholesale & retail | 2026 |
| KMD Classic Replicas Ltd | Manufacturing | 2010 |
| KMG & Sons Engineering Ltd | Manufacturing | 2003 |
| KMH Cleaning Limited | Administrative & support | 2012 |
| KMK LIM Trans Ltd | Transport & logistics | 2021 |
| Kmkn Limited | Wholesale & retail | 2018 |
| KML Trans Ltd | Transport & logistics | 2019 |
| KMP Logistics Limited | Construction | 2023 |
| KMS Property Investment Group Limited | Real estate | 2025 |
| Knad Automotive Ltd | Wholesale & retail | 2025 |
| Knellmore Homes Limited | Real estate | 2025 |
| Knight Catering Services Ltd | Manufacturing | 2011 |
| Knight D Limited | Wholesale & retail | 2007 |
| Knight Holdings Group Limited | Financial services | 2026 |
| Knight Investment Holdings Limited | Information & communication | 2026 |
| Knight Marine Limited | Manufacturing | 2013 |
| Knight Properties IW Ltd | Real estate | 2022 |
| Knightingale Couture Limited | Manufacturing | 2016 |
| Knights Communications Ltd | Professional & scientific | 2013 |
| Knights Contracting Ltd | Construction | 2026 |
| Knights Electrical & Plumbing Limited | Construction | 2021 |
| Knights Engineering & Fabrication Ltd | Manufacturing | 2023 |
| Knights Grove (North Baddesley) Management Company Limited | Households | 2004 |
| Knights PAT Testing Ltd | Construction | 2024 |
| Knights Prestige Estates Ltd | Real estate | 2025 |
| Knightsbrook Property Group Ltd | Other services | 2017 |
| Knightwood Executive Protection Ltd | Administrative & support | 2026 |
| Knightwood Oak Estates Ltd | Real estate | 2025 |
| KNM Building Services Ltd | Construction | 2019 |
| Knowexski Ltd | Information & communication | 2024 |
| Knowingbenefits Ltd | Wholesale & retail | 2021 |
| Knowl Hill Ltd | Construction | 2003 |
| Knowl Hill Sandpit Limited | Other services | 1997 |
| Knowler and SON Limited | Real estate | 2002 |
| Knowler Property Ltd | Real estate | 2026 |
| Knowsley Crescent 1970 Limited | Extraterritorial | 2014 |
| KO Beauty Limited | Other services | 2024 |
| KO Electrical Solutions Ltd | Construction | 2018 |
| Koala Marketing Limited | Information & communication | 2019 |
| Kobanah Limited | Professional & scientific | 2015 |
| Kobilz Cleaning Services Ltd | Administrative & support | 2020 |
| Kode Architecture Limited | Professional & scientific | 2013 |
| Koedan Construction Ltd | Construction | 2025 |
| Kogo Fresh Ltd | Wholesale & retail | 2026 |
| Kohinoor of Kerala (Southampton) Limited | Hospitality | 2019 |
| Kohistan Ltd | Transport & logistics | 2025 |
| Kojii Ltd | Wholesale & retail | 2025 |
| Koki Group UK Limited | Wholesale & retail | 1997 |
| Kolectric Research Limited | Manufacturing | 1994 |
| Kolman Ltd | Transport & logistics | 2015 |
| Kolmar Trans Limited | Transport & logistics | 2019 |
| Kololo Limited | Financial services | 2024 |
| Kolstoe Consulting Ltd | Information & communication | 2024 |
| Komidive Ltd | Information & communication | 2018 |
| Kommunications Design Services Limited | Information & communication | 2004 |
| Kompara Ltd | Construction | 2026 |
| Komplai Ltd | Information & communication | 2021 |
| Komvos Consulting Ltd | Professional & scientific | 2017 |
| Konasoft Limited | Information & communication | 1998 |
| Kongs (UK) Limited | Financial services | 2005 |
| Konnect Group Holdings Ltd | Other services | 2019 |
| Konnect Recruit South East Ltd | Administrative & support | 2019 |
| Konnect Recruit South West Limited | Administrative & support | 2021 |
| Konnect Recruit Southern Ltd | Administrative & support | 2016 |
| Konstruktion Ltd | Construction | 2026 |
| Kookie Tattoo Limited | Other services | 2017 |
| Koolkompany Ltd | Wholesale & retail | 2015 |
| Koray Limited | Hospitality | 2025 |