| Karolinaneimet Limited | Health & social care | 2015 |
| Kars Coastal Limited | Real estate | 2021 |
| Kars Cotswolds Limited | Real estate | 2022 |
| Kars Investments Ltd | Real estate | 2015 |
| Kars Somerset Limited | Real estate | 2022 |
| Kasa Developments Ltd | Real estate | 2024 |
| Kate Ringsell Casting Limited | Information & communication | 2015 |
| Katei Ltd | Real estate | 2021 |
| Kathmandu Dinner Ltd | Hospitality | 2019 |
| Kati Leisure Limited | Hospitality | 2025 |
| Katie Jarvis Photography Limited | Professional & scientific | 2026 |
| Katie Oldknow Ltd | Wholesale & retail | 2018 |
| Kaymech Precision Limited | Manufacturing | 2021 |
| Kaymech Solutions Ltd | Manufacturing | 2018 |
| KAZ Barber 3 Limited | Other services | 2024 |
| KB Properties (Derbyshire) Limited | Real estate | 2021 |
| KC Bathrooms Limited | Wholesale & retail | 2024 |
| KC Security Ltd | Administrative & support | 2024 |
| Kc-Iccp-Mgps Ltd | Extraterritorial | 2023 |
| KCS Electrical and Security Contractors Ltd | Construction | 2018 |
| KCW Training and Consultancy Ltd | Education | 2026 |
| KDM Training Ltd | Professional & scientific | 2011 |
| Keeley Flint Market Services Ltd | Professional & scientific | 2014 |
| Keeling Consultancy Ltd | Professional & scientific | 2025 |
| Keep Glapwell Green Limited | Financial services | 2025 |
| Keesoft Ltd | Information & communication | 2016 |
| KEI Services Ltd | Professional & scientific | 2019 |
| Keiko Learning and Consultancy Ltd | Professional & scientific | 2025 |
| Keiko Osaka Limited | Wholesale & retail | 2019 |
| Keith Bradshaw Limited | Professional & scientific | 2020 |
| Kellie Property Group Ltd | Hospitality | 2024 |
| KEM Property Group Ltd | Real estate | 2025 |
| Kemp Resells Ltd | Wholesale & retail | 2026 |
| Kemp Trading Ltd | Wholesale & retail | 2024 |
| Kenyon Consultative Ltd | Financial services | 2025 |
| Kerry B Bars Limited | Hospitality | 2021 |
| Kerry G Bars Chesterfield Limited | Hospitality | 2025 |
| Kerry G Bars Mansfield Limited | Hospitality | 2025 |
| Kersal Management Limited | Real estate | 1987 |
| Kersal Mount Limited | Extraterritorial | 1986 |
| KES Plumbing & Heating Limited | Construction | 2003 |
| Keval Developments Ltd | Construction | 2019 |
| Keval Ltd | Administrative & support | 2021 |
| Kevin G. Mather Transport Limited | Transport & logistics | 2003 |
| Kevin Harris Consulting Limited | Professional & scientific | 2024 |
| Kevin James Overton Limited | Extraterritorial | 2025 |
| Kevin Jones Plumbing & Heating Limited | Construction | 2009 |
| Key and Bar Property Ltd | Real estate | 2025 |
| Key Electrical Contractors Ltd | Construction | 2026 |
| Key Mortgage Management Limited | Financial services | 2007 |
| Keystone Financial Limited | Financial services | 2009 |
| Keystone Labour Solutions Limited | Administrative & support | 2025 |
| Keystone Supplies Limited | Wholesale & retail | 2013 |
| Keyturn Property Group Ltd | Real estate | 2025 |
| KGB Developments Limited | Construction | 2007 |
| KH Hospitalities Services Ltd | Hospitality | 2025 |
| KH Special Projects Ltd | Information & communication | 2022 |
| Khaleia Aesthetic Ltd | Other services | 2026 |
| KHE Site Services Limited | Construction | 2024 |
| Khrpdevelopments Ltd | Real estate | 2025 |
| Ki-Ki's Hair and Beauty Ltd | Other services | 2021 |
| Kiar Limited | Transport & logistics | 2019 |
| Kickers Dance Studios Limited | Arts & recreation | 2004 |
| Kickers Studios Limited | Arts & recreation | 2009 |
| Kids Zone Ltd | Education | 2013 |
| KIE Developments Limited | Construction | 2004 |
| Kielder Computers Limited | Information & communication | 1985 |
| Kieran Clarke Green Ltd | Professional & scientific | 2015 |
| Kieran Hill Consultancy Ltd | Professional & scientific | 2023 |
| Killingley Holdings Ltd | Financial services | 2019 |
| Kindarcats Limited | Education | 2008 |
| Kinective Ltd | Construction | 2024 |
| Kinesic Limited | Wholesale & retail | 2025 |
| Kingdom Music Academy CIC | Information & communication | 2025 |
| Kingfield Electronics Limited | Manufacturing | 1985 |
| Kings Cross Plumbing Ltd | Construction | 2018 |
| Kingswood Park Management Company (Wingerworth) Ltd | Households | 2025 |
| Kingwood Hire Limited | Administrative & support | 2025 |
| Kinibay Associates Limited | Administrative & support | 1995 |
| Kinsiz Properties Limited | Real estate | 2025 |
| Kinyaga Limited | Health & social care | 2017 |
| KIP Mcgrath Chesterfield West LLP | | 2023 |
| Kirk's Property Services Ltd | Real estate | 2022 |
| Kirkby Developments Limited | Real estate | 2004 |
| Kirkstone Property Ltd | Real estate | 2025 |
| Kirsty Leanne Thacker Ltd | Extraterritorial | 2025 |
| Kirsty's Cleaning Ltd | Administrative & support | 2022 |
| Kismet Counselling Services Ltd | Health & social care | 2019 |
| Kitchen Craft Design Limited | Wholesale & retail | 2013 |
| Kitchen Makeover Store Limited | Wholesale & retail | 2024 |
| Kitchen Revive Company Ltd | Construction | 2022 |
| Kiwi Property Ltd | Real estate | 2020 |
| Kiwi Solutions Ltd | Other services | 2023 |
| Kizza's Kandies Ltd | Wholesale & retail | 2023 |
| KJB Vehicles Ltd | Wholesale & retail | 2022 |
| KJM Properties Limited | Construction | 2011 |
| KJS UK Services Ltd | Transport & logistics | 2017 |
| KLS Comms Ltd | Information & communication | 2021 |
| KLS Kebab Ltd | Hospitality | 2026 |
| KM Cotton Ltd | Wholesale & retail | 2025 |