| K L Change Ltd | Information & communication | 2021 |
| K Neale Limited | Education | 2021 |
| K S a P Services Limited | Health & social care | 2016 |
| K Street Fisheries Ltd | Hospitality | 2026 |
| K T Installations Ltd | Construction | 2012 |
| K&A Housing Ltd | Real estate | 2021 |
| K&E Property Limited | Real estate | 2019 |
| K&K Medent Limited | Health & social care | 2013 |
| K&R Installations Limited | Construction | 2022 |
| K-Lab Fabrications Ltd | Manufacturing | 2026 |
| K. Hundal Property Group Ltd | Real estate | 2025 |
| K. Shaw Limited | Professional & scientific | 2010 |
| K. T. Excavations Limited | Water & waste | 2018 |
| K.A.S Roofing Ltd | Construction | 2019 |
| K.A.W.A. Vent Ltd | Manufacturing | 2020 |
| K.B. Industries UK Ltd | Construction | 2010 |
| K.S. Transport (UK) Limited | Transport & logistics | 2007 |
| K20 Projects Limited | Real estate | 2023 |
| KAI Frostick Ltd | Real estate | 2025 |
| Kaij Ltd | Wholesale & retail | 2024 |
| Kale Copywriting Ltd | Professional & scientific | 2022 |
| Kale Group Ltd | Financial services | 2024 |
| Kale Property Ltd | Real estate | 2024 |
| Kaloki Family Company Limited | Financial services | 2024 |
| Kaloyan Transport Limited | Transport & logistics | 2018 |
| Kamazani Ltd | Wholesale & retail | 2026 |
| Kamtrak Ltd | Transport & logistics | 2017 |
| Kansa Limited | Manufacturing | 2011 |
| Kaplar Developments Limited | Construction | 2024 |
| Karick Limited | Professional & scientific | 2026 |
| Karl Lindley Limited | Construction | 2015 |
| Karlmarx Holdings Limited | Financial services | 2018 |
| Karma Cleaners Limited | Administrative & support | 2019 |
| Karpiel Solutions Ltd | Real estate | 2024 |
| Kashmiri Cooks Ltd | Hospitality | 2024 |
| KAT Homes Limited | Real estate | 2016 |
| Kate Thorpe Ltd | Professional & scientific | 2019 |
| Katy Craig Limited | Wholesale & retail | 2010 |
| Katy's Boutique UK Ltd | Wholesale & retail | 2021 |
| Kay's Cafe Limited | Wholesale & retail | 2007 |
| Kaya 2020 Ltd | Hospitality | 2019 |
| Kaye Holdings Limited | Financial services | 2022 |
| Kaylin Health Ltd | Health & social care | 2022 |
| Kaylock Estates Ltd | Real estate | 2016 |
| Kays Insurance Brokers Limited | Financial services | 2013 |
| KB Furnishing Ltd | Construction | 2025 |
| KB Marketing Ltd | Professional & scientific | 2026 |
| KBD Developments Ltd | Real estate | 2025 |
| KBM Property Group Limited | Real estate | 2025 |
| KC Academy HQ Ltd | Education | 2025 |
| KC Flooring and Property Limited | Construction | 2025 |
| KC Pharmaceuticals Ltd | Wholesale & retail | 2023 |
| KDA Wholesales Ltd | Wholesale & retail | 2004 |
| Kdselfcare Limited | Health & social care | 2025 |
| Kdsm Ltd | Hospitality | 2000 |
| Keamast Ltd | Wholesale & retail | 2025 |
| Kebab&Pizza Barnsly Limited | Hospitality | 2021 |
| Keel Inn Motel Ltd | Hospitality | 2025 |
| Keelings Fish and Chips Ltd | Hospitality | 2025 |
| Keen GAS Services Ltd | Construction | 2025 |
| Keith Mawby (Property) Limited | Real estate | 2017 |
| Keith Pedigree Limited | Financial services | 2016 |
| KEL Electrical Limited | Construction | 2015 |
| Keland Rentals Ltd | Real estate | 2025 |
| Kelham Treasures Ltd | Manufacturing | 2023 |
| Kellett (UK) Limited | Extraterritorial | 1919 |
| Kelo Precision Engineering Limited | Professional & scientific | 2022 |
| Kels Cuisine Ltd | Hospitality | 2026 |
| Kemill Limited | Real estate | 1963 |
| KEN Mallinson & Sons Holdings Limited | Financial services | 2017 |
| KEN Mallinson & Sons Limited | Transport & logistics | 1996 |
| Kendall Holdings UK Limited | Professional & scientific | 2007 |
| Kendall Retail Operations Consultants Ltd | Professional & scientific | 2025 |
| Kenilworth Claim Limited | Other services | 2000 |
| Kensa Chemicals Limited | Manufacturing | 1987 |
| Kensington Leverne Ltd | Professional & scientific | 2023 |
| Kensington Road Limited | Households | 2017 |
| Kent Alarms (Maintenance) Limited | Manufacturing | 2011 |
| Kent Alarms Limited | Administrative & support | 2003 |
| Kent-Rogers Holdings Limited | Financial services | 2020 |
| Kent-Rogers Investments Limited | Real estate | 2020 |
| Kent-Rogers Medico-Legal Reporting Limited | Health & social care | 2014 |
| Kenthworth Group Limited | Wholesale & retail | 2025 |
| Kenworthy Ltd | Real estate | 2025 |
| Ken’S KEG and Cask Limited | Wholesale & retail | 2023 |
| Keppel Consulting Limited | Administrative & support | 2020 |
| Keptcastle Estates Limited | Real estate | 2009 |
| Kerry's House of Flowers Ltd | Wholesale & retail | 2021 |
| Kerrys Blinds Limited | Wholesale & retail | 2014 |
| Kershaw Surfacing Ltd | Construction | 2024 |
| Kest Ltd | Construction | 2025 |
| Kestrel Estates UK Ltd | Real estate | 2016 |
| Kestrel Imaging Limited | Professional & scientific | 2018 |
| Kestrel Motorhomes Limited | Wholesale & retail | 2022 |
| Ketton Property Limited | Real estate | 2025 |
| Kevin Blanco Ltd | Wholesale & retail | 2019 |
| Keystage Teacher Supply Limited | Administrative & support | 2000 |
| Keystone Property Investments Group Ltd | Households | 2025 |
| KF MEP Services Ltd | Professional & scientific | 2022 |
| KFF Electrical Ltd | Construction | 2016 |