| Kalra Trading Limited | Wholesale & retail | 2025 |
| Kamtex Limited | Professional & scientific | 2014 |
| Kannde Investment Ltd | Real estate | 2018 |
| Kanz Partners Ltd | Information & communication | 2026 |
| Karabatak International Consulting Ltd | Wholesale & retail | 2024 |
| Karas Design and Build Ltd | Construction | 2019 |
| Karimjee Jivanjee & Co.(U.K.)Limited | Extraterritorial | 1961 |
| Karl Mcfeely Refurbishments Ltd | Construction | 2020 |
| Karma Consultants Ltd | Professional & scientific | 2020 |
| Karma Fitness Ltd | Wholesale & retail | 2020 |
| Kath & Company Limited | Arts & recreation | 2019 |
| Kathmandu Tandoori Ltd | Hospitality | 2019 |
| Katie Bleach Ltd | Arts & recreation | 2016 |
| Katie Rose Medical Aesthetics Ltd | Other services | 2023 |
| Katie's Nails Limited | Other services | 2023 |
| Katy MAC Ltd | Wholesale & retail | 2026 |
| KAZ Limited | Real estate | 2020 |
| KBO Contractors Ltd | Construction | 2025 |
| KC Construction (Group) Ltd | Construction | 2025 |
| KC Group Properties Ltd | Real estate | 2024 |
| KD MOB Records Ltd | Arts & recreation | 2023 |
| KE & TE Limited | Wholesale & retail | 2023 |
| Keane Learning & Mentoring Limited | Education | 2012 |
| Keca Ltd | Wholesale & retail | 2024 |
| Keene Consultants Ltd | Professional & scientific | 2023 |
| Keep Homes (Cresta) Ltd | Real estate | 2022 |
| Keep Homes Limited | Construction | 2016 |
| Keep on the Grass! Ltd | Administrative & support | 2025 |
| Kelixio Ltd | Wholesale & retail | 2015 |
| Kellcad Limited | Construction | 2023 |
| Kelmscott Associates Consulting Ltd | Professional & scientific | 2019 |
| Kelvault Ltd | Information & communication | 2025 |
| Kempgrove Limited | Professional & scientific | 2013 |
| Kendra International Ltd | Professional & scientific | 2022 |
| Kendrey Consultancy Limited | Professional & scientific | 2020 |
| Kenley RD Twickenham Limited | Real estate | 2021 |
| Kenningham Retail LLP | | 2012 |
| Kepta Limited | Wholesale & retail | 2018 |
| Kernel Investments Limited | Financial services | 2022 |
| Kernow Boats (Oars) Limited | Manufacturing | 2018 |
| Kernow Boats Limited | Manufacturing | 2019 |
| Kevoc Ltd | Professional & scientific | 2023 |
| KEW Home Limited | Construction | 2012 |
| Kewhaven Pictures Ltd | Information & communication | 2002 |
| KGB Accountancy Ltd | Professional & scientific | 2013 |
| KGG Properties Ltd | Real estate | 2022 |
| KGP Property Limited | Real estate | 2019 |
| Khan Properties One Ltd | Real estate | 2023 |
| Khanani's Limited | Wholesale & retail | 2024 |
| KHL Estates Limited | Real estate | 2020 |
| Khubal Ltd | Information & communication | 2025 |
| Kian Holdings Ltd | Financial services | 2022 |
| Kiara Wines Limited | Wholesale & retail | 2023 |
| Kick Hair Limited | Administrative & support | 2004 |
| Kiddy Cook South West London Ltd | Hospitality | 2024 |
| Kidworth Limited | Other services | 2018 |
| Kidz Town Limited | Arts & recreation | 2025 |
| Kilkee Services Ltd | Construction | 2019 |
| KIM Poor Limited | Professional & scientific | 1996 |
| KIN Entertainment Ltd | Information & communication | 2013 |
| Kinder Consulting Ltd | Professional & scientific | 2020 |
| Kinglake Limited | Wholesale & retail | 2024 |
| Kingsnet Ltd. | Professional & scientific | 2014 |
| Kingston Hill Developments Limited | Construction | 2025 |
| Kintaugh Limited | Professional & scientific | 2026 |
| KIO Property Group Ltd | Real estate | 2019 |
| Kirby Wilkinson Picture Company Ltd | Information & communication | 2025 |
| Kirei Limited | Wholesale & retail | 2007 |
| Kirkpatrick Associates Limited | Wholesale & retail | 2015 |
| Kitchen Management Limited | Wholesale & retail | 2008 |
| Kixa Consultancy Ltd | Professional & scientific | 2025 |
| Kixa Finance Ltd | Financial services | 2020 |
| Kixa Limited | Real estate | 2020 |
| Kixa Properties LLP | | 2020 |
| Kiyetec Solutions Ltd | Transport & logistics | 2015 |
| KJC Technical Services Limited | Professional & scientific | 2025 |
| Kjmd Technologies Ltd | Information & communication | 2025 |
| KKM Contracts Ltd | Construction | 2010 |
| KL Recording Limited | Information & communication | 2024 |
| Klad Property Management Limited | Real estate | 2025 |
| Klay Artists Limited | Arts & recreation | 2023 |
| Klay Holdings Limited | Financial services | 2023 |
| Klay Team Limited | Hospitality | 2023 |
| Klein Industry Ltd | Wholesale & retail | 2021 |
| Klipper Club Ltd | Other services | 2022 |
| KM Kale Ltd | Health & social care | 2023 |
| KM Watkins Consulting Limited | Professional & scientific | 2008 |
| KMG Consulting Services Ltd | Professional & scientific | 2017 |
| KMR Spaces Ltd | Real estate | 2025 |
| Kmtr Riders Ltd | Administrative & support | 2026 |
| Knacktarget Limited | Arts & recreation | 1987 |
| Kneller Road Limited | Construction | 2017 |
| KNG Construction Ltd | Construction | 2025 |
| Knightsbridge London Holdings Ltd | Hospitality | 2021 |
| Knots Developments Limited | Construction | 2025 |
| Koantum Technologies Ltd | Information & communication | 2026 |
| Kobe One Ltd | Administrative & support | 2016 |
| Kobudai Ltd | Information & communication | 2018 |
| Koil Ltd | Health & social care | 2014 |
| Koko Nail Richmond Ltd | Other services | 2022 |