| Kiaan Ltd | Administrative & support | 2017 |
| Kiambu Ltd | Other services | 2016 |
| Kiboko Life Ltd | Wholesale & retail | 2024 |
| KIC Machines Limited | Wholesale & retail | 2016 |
| Kickin Ltd | Real estate | 2023 |
| Kidan Limited | Wholesale & retail | 2021 |
| Kidare Development Ltd | Information & communication | 2009 |
| Kikwalo Ltd | Administrative & support | 2022 |
| Kilcullen Homes (UK) LLP | | 2009 |
| Killierisk Investment Holding Company UK Limited | Financial services | 2021 |
| Kilroy Consulting Ltd | Professional & scientific | 2015 |
| KIM Rance Limited | Other services | 2021 |
| KIM Tasker Interiors Ltd | Professional & scientific | 2020 |
| Kimas UK Service Ltd | Administrative & support | 2026 |
| KIN Estates Ltd | Real estate | 2024 |
| KIN Music Ltd | Arts & recreation | 2017 |
| Kind Solutions Limited | Administrative & support | 2014 |
| Kindling Money Ltd | Financial services | 2023 |
| Kinetic Capital Solutions Ltd | Administrative & support | 2025 |
| Kinetic Knight Ltd | Hospitality | 2025 |
| Kinetic Software Solutions Limited | Information & communication | 2008 |
| Kinetic Sports Consultancy Ltd | Health & social care | 2019 |
| Kingdom Bridge Estates Ltd | Real estate | 2026 |
| Kingdom Key Ltd | Real estate | 2024 |
| Kingdom Street Invest LLP | | 2024 |
| Kingo Services Ltd | Administrative & support | 2024 |
| Kings Court (Chelsea) Limited | Households | 1983 |
| Kings Court Chelsea NO. 2 Limited | Real estate | 2007 |
| Kingsbury Link Management Limited | Professional & scientific | 1977 |
| Kingsend Ruislip (Number 41) Management Company Limited | Real estate | 2007 |
| Kingsford Digital Limited | Wholesale & retail | 2026 |
| Kingson Electrical Limited | Construction | 2005 |
| Kingspark Stores Limited | Wholesale & retail | 2019 |
| Kingston (Ravensthorpe) Ltd | Construction | 2018 |
| Kingston Civils Limited | Construction | 2025 |
| Kingston Property Holdings Ltd | Construction | 2018 |
| Kingston Real Estate (New Homes) Limited | Construction | 2015 |
| Kingston Real Estate (Property Management) Limited | Real estate | 2017 |
| Kingston Real Estate Limited | Real estate | 2012 |
| Kingston Regent Ltd | Administrative & support | 2014 |
| Kingstone Capital Ltd | Real estate | 2026 |
| Kingswood Fitted Wardrobes Ltd | Manufacturing | 2022 |
| Kingswood Heating Limited | Construction | 2017 |
| Kingswood Specialist Glazing Limited | Construction | 2009 |
| Kingswood Supplies Limited | Wholesale & retail | 2000 |
| Kinik Trends Limited | Wholesale & retail | 2015 |
| Kins West Trading Co. Ltd | Wholesale & retail | 2024 |
| Kinsey Whitehouse Ltd | Information & communication | 2011 |
| Kinu Beauty Ltd | Other services | 2026 |
| Kiran Mahmood Health Ltd | Health & social care | 2013 |
| Kiran Tech Consulting Limited | Information & communication | 2014 |
| Kirkham Services Ltd | Construction | 2025 |
| Kirsty Bowman Limited | Professional & scientific | 2024 |
| Kirsty Marrins Ltd | Professional & scientific | 2017 |
| Kisa Investments Ltd | Health & social care | 2020 |
| Kisa Optical Ltd | Health & social care | 2024 |
| Kiseru Consulting Ltd. | Information & communication | 2016 |
| Kishara Limited | Health & social care | 2022 |
| Kishore Consulting Limited | Information & communication | 2007 |
| Kisim Construction Ltd | Construction | 2026 |
| Kismat Beats Limited | Other services | 2011 |
| Kiss by Nature Ltd | Wholesale & retail | 2023 |
| Kissanes Ltd | Other services | 2018 |
| Kisss Limited | Administrative & support | 2017 |
| Kitch Developments Limited | Construction | 2018 |
| Kitch Holdings Limited | Real estate | 2025 |
| Kitch Investments Limited | Financial services | 2018 |
| Kitchenaid UK Limited | Wholesale & retail | 2023 |
| Kitson's Insulation Contractors Limited | Construction | 1965 |
| Kitten Limited | Information & communication | 2022 |
| Kiwi Drainage Limited | Water & waste | 2004 |
| KJ Infosolutions Limited | Information & communication | 2010 |
| KJB Time & Art Limited | Wholesale & retail | 2007 |
| KJP Innovations Limited | Wholesale & retail | 2024 |
| KJR Systems Ltd | Information & communication | 2013 |
| KK Digital Consulting Limited | Professional & scientific | 2025 |
| KK Starr Ltd | Real estate | 2017 |
| KK Unique Property Investments Limited | Real estate | 2018 |
| Kk-Am Groups Ltd | Hospitality | 2026 |
| KKG Property Ltd | Real estate | 2019 |
| KKP Trade Ltd | Wholesale & retail | 2025 |
| Kkpd Limited | Transport & logistics | 2017 |
| KKS Solutions Limited | Health & social care | 2022 |
| KL Auto Engineers Limited | Manufacturing | 2025 |
| KL London Limited | Information & communication | 2013 |
| KLA Property Investment Ltd | Real estate | 2021 |
| Klaassen Property Maintenance Ltd | Construction | 2020 |
| Klavie Ltd | Wholesale & retail | 2024 |
| Klean Property Services Ltd | Administrative & support | 2017 |
| Klear Limited | Hospitality | 2020 |
| Klenzify Ltd | Administrative & support | 2023 |
| KLF Supplies & Admin Support Limited | Administrative & support | 2024 |
| Klia LLP | | 2009 |
| Klickstart Ltd | Professional & scientific | 2019 |
| KLN Installation Ltd | Construction | 2025 |
| Kloss Consulting Limited | Professional & scientific | 2018 |
| KLY Improvements Ltd | Construction | 2019 |
| KM Kinetic Ltd | Health & social care | 2025 |
| KM Sales & Lettings Ltd | Real estate | 2024 |
| KMC Consulting Ltd | Professional & scientific | 2014 |