| KEO Engineering Services Ltd | Construction | 2024 |
| Kepa Solutions Limited | Information & communication | 2024 |
| Kernow and Mayfair Limited | Professional & scientific | 2013 |
| Kernpoint Ltd | Extraterritorial | 2022 |
| Kevandpra Limited | Professional & scientific | 2020 |
| Keys Real Estate Advisory Limited | Real estate | 2026 |
| Keyside Limited | Real estate | 1998 |
| Keysoe Riding Club Limited | Arts & recreation | 2019 |
| Keyston Consulting Ltd | Other services | 2026 |
| Keyston Farms Limited | Agriculture & fishing | 2013 |
| Keystone Building and Restoration Ltd | Construction | 2019 |
| Keytone Limited | Real estate | 2020 |
| Kgss Property Limited | Real estate | 2018 |
| KH Software Development Ltd | Information & communication | 2024 |
| Khosla Locums Ltd | Wholesale & retail | 2018 |
| Kickers Property Limited | Households | 2026 |
| Kids Entrepreneur Club Ltd | Education | 2022 |
| Kiem Consulting Ltd | Professional & scientific | 2022 |
| Kilverstone Grange (Thetford) Management Company Ltd | Real estate | 2006 |
| KIM Systems Limited | Manufacturing | 1991 |
| Kimbolton Financial Planning Limited | Financial services | 2015 |
| Kimbolton School | Education | 2003 |
| Kimbolton Spice Ltd | Hospitality | 2024 |
| Kimbolton Vets Limited | Professional & scientific | 2023 |
| Kimbolton Wills & Estate Planning Ltd | Financial services | 2017 |
| Kimuli Group Ltd | Financial services | 2024 |
| Kindred Fellows Ltd | Construction | 2019 |
| Kingfisher Day Centre Limited | Health & social care | 2019 |
| Kings Waterfront Properties Limited | Extraterritorial | 2000 |
| Kingsley Kade Ltd | Manufacturing | 2021 |
| Kingston House Management Company Limited | Households | 1993 |
| Kinnaird Hill Accountants LLP | | 2019 |
| Kinnaird Hill Limited | Professional & scientific | 2000 |
| Kinnetic Limited | Professional & scientific | 2026 |
| Kinsfaun Consultancy Limited | Professional & scientific | 2026 |
| Kiosk Barbers Limited | Professional & scientific | 2013 |
| Kirschner Cleaning Limited | Administrative & support | 2019 |
| Kirtlington Park Polo Club Limited | Arts & recreation | 2018 |
| Kirton Construction (Design & Build) Limited | Real estate | 1976 |
| Kisival Ltd | Administrative & support | 2025 |
| Kitaki Ltd | Professional & scientific | 2018 |
| Kitchen 2 Commercial Ltd | Wholesale & retail | 2018 |
| Kitchen Range Foods Limited | Manufacturing | 1971 |
| Kitchen TEN Limited | Hospitality | 2025 |
| Kittylee Art Ltd | Arts & recreation | 2020 |
| Kiwi Aviation Ltd | Transport & logistics | 2020 |
| KJ Composites Ltd | Manufacturing | 2026 |
| KJS GAS Services Ltd | Construction | 2012 |
| KKD Footwear Ltd | Professional & scientific | 2025 |
| Kkrz GB Ltd | Transport & logistics | 2018 |
| KL Thompkins Trading Ltd | Financial services | 2026 |
| KLC Electrical Ltd | Construction | 2013 |
| KLM Engineering UK Limited | Extraterritorial | 2007 |
| KLM Family Investment Company Limited | Extraterritorial | 2017 |
| KLM Investments Limited | Manufacturing | 1982 |
| KLN Estates Ltd | Administrative & support | 2016 |
| Kloeber Holdings Limited | Financial services | 2013 |
| Kloeber UK Ltd | Wholesale & retail | 2006 |
| KMB Security & Cleaning Services Limited | Administrative & support | 2014 |
| Kmml Trading Ltd | Wholesale & retail | 2020 |
| Kmmt Haulage Limited | Transport & logistics | 2019 |
| Knightwatch Cyber Security Solutions Ltd | Information & communication | 2024 |
| Komshu 132 Ltd | Hospitality | 2026 |
| Kontained Labs Ltd | Other services | 2025 |
| KP Commercial Services Limited | Professional & scientific | 2009 |
| Kp's Electric's Ltd | Construction | 2026 |
| Kratos Gym Ltd | Arts & recreation | 2021 |
| Krishevseb Ltd | Households | 2024 |
| Kristiana Enterprise Limited | Financial services | 2012 |
| Kruger Cowne Rights Limited | Information & communication | 2026 |
| Kruger Plumbing Ltd | Construction | 2020 |
| KS Aviation Services Ltd | Professional & scientific | 2019 |
| KS Secretarial Services Limited | Administrative & support | 2022 |
| KT Composites Ltd | Manufacturing | 2026 |
| KT Haulage Ltd | Transport & logistics | 2021 |
| Ktal Building and Landscape Services Limited | Construction | 2024 |
| KTS Computers Ltd | Other services | 2003 |
| Kudu Hospitality Limited | Hospitality | 2026 |
| Kudu Rooms Limited | Hospitality | 2026 |
| Kushe Home Ltd | Wholesale & retail | 2026 |
| Kwikstaart Investments Limited | Real estate | 2023 |
| KYM View Close Management Company Limited | Households | 2021 |
| L B Warehousing Limited | Administrative & support | 2009 |
| L G D Body & Paint Ltd | Wholesale & retail | 2026 |
| L G Steel Fixing Ltd | Construction | 2023 |
| L J Project Management Limited | Administrative & support | 2022 |
| L J S Design & Build Ltd. | Real estate | 2016 |
| L J S Homes Ltd. | Construction | 2016 |
| L R Boon & Sons Limited | Manufacturing | 2007 |
| L&R Removals Ltd | Transport & logistics | 2024 |
| L'Affaire DU Parfum Ltd | Wholesale & retail | 2025 |
| L. Ingle Contracting Services Ltd | Professional & scientific | 2014 |
| L.C.J. Mountain Farms Limited | Agriculture & fishing | 2003 |
| L.J.A.Miers & Company Limited | Manufacturing | 1954 |
| L.K.A Marketing Ltd | Professional & scientific | 2021 |
| L.P.P.S. Limited | Real estate | 2006 |
| L.R. Clayton Limited | Wholesale & retail | 1975 |
| L.T. Izzard (Electrical) Limited | | 1978 |
| LA Ballers Ltd | Arts & recreation | 2023 |
| LA Cladding Limited | Construction | 2005 |