| Kallar Holdings Limited | Financial services | 2021 |
| Kallar Property Agents Limited | Financial services | 2025 |
| Kalra Property Group Ltd | Real estate | 2019 |
| Kamiham General Ltd | Wholesale & retail | 2026 |
| Kamko Consultants Limited | Administrative & support | 2017 |
| Kamtec Lifescience Partners Limited | Professional & scientific | 2017 |
| Kanani Ltd | Other services | 2016 |
| Kaneglen Properties Limited | Administrative & support | 1980 |
| Kangaroo Tuition Ltd | Education | 2023 |
| Kapporeth Care Services Limited | Administrative & support | 2025 |
| KAR Digital Limited | Professional & scientific | 2026 |
| Karamjot | Health & social care | 2010 |
| Karma Communications Limited | Professional & scientific | 2020 |
| Kasastore Limited | Wholesale & retail | 2014 |
| Katala Education Ltd | Information & communication | 2020 |
| Kate Barclay Consulting Limited | Professional & scientific | 2016 |
| Kate Carpenter Medical Communications Limited | Extraterritorial | 2019 |
| Kate Vincent Photography Limited | Professional & scientific | 2019 |
| Katie Winterbourne Art Limited | Arts & recreation | 2020 |
| Katie Winterbourne Limited | Other services | 2013 |
| Kaur Healthcare Ltd | Extraterritorial | 2018 |
| Kavanagh Property Group Ltd | Real estate | 2019 |
| Kavita Consultancy Limited | Health & social care | 2014 |
| KB Tree Surgery Ltd | Administrative & support | 2023 |
| KBA Properties Ltd | Hospitality | 2023 |
| KC Private Capital Limited | Financial services | 2026 |
| KC Private Clients Limited | Other services | 2018 |
| KD Drug Discovery Ltd | Professional & scientific | 2026 |
| KD Ponds T/A Women With Waders Limited | Administrative & support | 2023 |
| KDZ Solutions Ltd | Wholesale & retail | 2023 |
| Keats Way Management Company (Hitchin) Limited | Households | 1984 |
| Keegan Lighting Limited | Information & communication | 2013 |
| Keegan Property Management Limited | Real estate | 2004 |
| Keelings Accountancy Group Limited | Financial services | 2019 |
| Keelings Group Audit Limited | Professional & scientific | 2019 |
| Keep-Fit 4U Ltd | Arts & recreation | 2019 |
| Kelly Home Staging Ltd | Real estate | 2011 |
| Kemco Conveyors Limited | Manufacturing | 1995 |
| Kemitech Limited | Information & communication | 2019 |
| KEN Pope Custom Joinery Ltd | Manufacturing | 2022 |
| Kenba Solutions Ltd | Wholesale & retail | 2023 |
| Kenhurst Fresh Foods Limited | Hospitality | 2022 |
| Kennion Associates Limited | Professional & scientific | 2011 |
| Kerburn Gold Limited | Information & communication | 2015 |
| Kerburn Media Limited | Professional & scientific | 2005 |
| Kerr & Co Hospitality Ltd | Hospitality | 2025 |
| Kerry Kane Limited | Health & social care | 2018 |
| Kestral Accountancy Solutions Ltd | Professional & scientific | 1987 |
| Key Events Limited | Professional & scientific | 1995 |
| Key Project Property Investment Limited | Real estate | 2013 |
| Keycounsel Limited | Other services | 2006 |
| Keyline Lettings Ltd | Real estate | 2024 |
| Keysheath Investment Company Limited | Construction | 1956 |
| Keyspace Collective Limited | Real estate | 2026 |
| Kez's DRY Cleaners Limited | Other services | 2008 |
| KG Media Ltd | Information & communication | 2023 |
| Khai Solutions Ltd | Administrative & support | 2025 |
| Khaya's House Ltd | Real estate | 2025 |
| Kibb's Construction Ltd | Construction | 2022 |
| Kicktrix Limited | Manufacturing | 2014 |
| Kidd Consultancy Ltd | Professional & scientific | 2025 |
| Kids on the Move Physio Ltd | Health & social care | 2025 |
| Kilmac Property Ltd | Hospitality | 2024 |
| Kiln Dried Logs London Ltd | Agriculture & fishing | 2018 |
| KIM 147 Limited | Real estate | 2025 |
| KIM Construction Limited | Construction | 1987 |
| KIM Trading Limited | Real estate | 1991 |
| Kimberley Systems Engineering Limited | Professional & scientific | 2013 |
| Kimpton Cricket Club Ltd | Arts & recreation | 2020 |
| Kimpton Express Ltd | Hospitality | 2022 |
| Kimpton Garages Management Limited | Real estate | 2006 |
| Kimpton Park Consulting Ltd | Professional & scientific | 2021 |
| Kimpton Spice Herts Ltd | Hospitality | 2018 |
| Kimpton Tennis Club Ltd | Arts & recreation | 2024 |
| Kind, Coin & Soho Limited | Administrative & support | 2009 |
| Kingfisher Henlow Ltd | Arts & recreation | 2023 |
| Kinglet Properties Ltd. | Real estate | 2016 |
| Kings Ripton Farms Limited | Agriculture & fishing | 1987 |
| Kingsmead Lettings Limited | Real estate | 2017 |
| Kingsmead Rock Limited | Hospitality | 2000 |
| Kingswood Heating Services Limited | Construction | 2014 |
| Kino Fuse Limited | Real estate | 2021 |
| Kino SCG Limited | Information & communication | 2018 |
| Kinstone Limited | Manufacturing | 2026 |
| Kirstin Goldring Consulting Ltd | Professional & scientific | 2026 |
| Kite Hitchin Limited | Hospitality | 2017 |
| KJ JET Solutions Ltd | Administrative & support | 2025 |
| Kjmsendtutoring Ltd | Education | 2024 |
| KJR Baldock Ltd | Hospitality | 2017 |
| KK UK Holdings Limited | Real estate | 2017 |
| Kkcat Limited | Real estate | 2026 |
| Klean Cosmetics Ltd | Wholesale & retail | 2026 |
| Kloudbase Limited | Administrative & support | 2018 |
| Klugman Distribution Services ( KDS ) Limited | Transport & logistics | 2014 |
| KMH Developments Limited | Construction | 2011 |
| KMR Rural Limited | Agriculture & fishing | 2026 |
| Knight Asset Holdings Ltd | Financial services | 2020 |
| Knight Renovations Limited | Construction | 2011 |
| Knight&Co Ltd | Real estate | 2024 |
| Knights Hill Property Limited | Hospitality | 2019 |