| K&E Diamond Cleaning Service Ltd | Administrative & support | 2024 |
| K&K OFF Licence Store Limited | Wholesale & retail | 2026 |
| K&N Jackson Properties Ltd | Real estate | 2021 |
| K-Serv Limited | Professional & scientific | 2019 |
| K-Tax Limited | Other services | 2005 |
| K. D. P. Wood Products Ltd | Wholesale & retail | 2026 |
| K.B.B. Management Limited | Financial services | 2019 |
| K.D.G.S. (2005) Limited | Extraterritorial | 2005 |
| K.J.S Transport Services Ltd | Wholesale & retail | 2023 |
| K.O Demolition Services Limited | Construction | 2026 |
| K.O Diamond Nails Ltd | Other services | 2023 |
| K.O.T.J Ltd | Wholesale & retail | 2019 |
| K2 Inns Limited | Hospitality | 2023 |
| K9 Club Ltd | Wholesale & retail | 2023 |
| K9 Protection Ltd | Information & communication | 2011 |
| Kaadsu Limited | Hospitality | 2015 |
| Kaamt Ltd | Hospitality | 2025 |
| Kada Coatings International Ltd | Extraterritorial | 2012 |
| Kada Coatings Ltd | Professional & scientific | 2004 |
| Kada Commercial Coatings Ltd | Manufacturing | 2021 |
| Kada Europe Ltd | Manufacturing | 2018 |
| Kadalco Ltd | Hospitality | 2026 |
| Kadiesillustrations Ltd | Wholesale & retail | 2025 |
| Kaffyray Ltd | Health & social care | 2025 |
| Kafo GUY Ltd | Health & social care | 2025 |
| Kahve Limited | Hospitality | 2025 |
| Kaid Bartlett Mechanical Ltd | Construction | 2026 |
| Kaippans Properties Limited | Real estate | 2019 |
| KAK International Group Ltd | Arts & recreation | 2019 |
| Kakn Property Limited | Real estate | 2023 |
| Kalexben Holdings Limited | Hospitality | 2016 |
| Kalkata Ltd | Hospitality | 2024 |
| Kallhub Ltd | Administrative & support | 2025 |
| Kally Davies Media Ltd | Information & communication | 2021 |
| Kalni Traders Ltd | Wholesale & retail | 2022 |
| Kamber Family Ltd | Hospitality | 2026 |
| Kameu Investment CC Ltd | Health & social care | 2025 |
| Kandara Trading (UK) Limited | Wholesale & retail | 2023 |
| Kanga:Stone Ltd | Hospitality | 2025 |
| Kannon UK Limited | Wholesale & retail | 2017 |
| Kanthi Limited | Other services | 2017 |
| Kany Shop Ltd | Wholesale & retail | 2026 |
| KAP Media Production Ltd | Professional & scientific | 2022 |
| Kareemcouriers Limited | Transport & logistics | 2023 |
| Karkloof Limited | Manufacturing | 2021 |
| Karl Jones & Sons Limited | Transport & logistics | 2005 |
| Karmaceuticals Ltd. | Hospitality | 2019 |
| Karolo Limited | Information & communication | 2011 |
| Kartel Security Ltd | Financial services | 2023 |
| Karthik Limited | Transport & logistics | 2026 |
| KAS Barber Newport Ltd | Other services | 2025 |
| Kasa Quartz UK Limited | Wholesale & retail | 2023 |
| Kaspas South Wales Ltd | Hospitality | 2021 |
| Kasvosve Limited | Health & social care | 2014 |
| Kate Golding Health and Wellbeing Ltd | Education | 2022 |
| Katie Colella Ltd | Professional & scientific | 2023 |
| Katon Ingram Holdings IW Limited | Financial services | 2015 |
| Katon Ingram Limited | Real estate | 1971 |
| Kausar Akbar Properties Limited | Real estate | 2025 |
| KAY Gower Ltd | Other services | 2022 |
| Kaya Barbers (NPT) Ltd | Other services | 2026 |
| Kaya Supermarket Ltd | Wholesale & retail | 2017 |
| Kayden Audio Visual Ltd | Wholesale & retail | 2023 |
| KB Burford Management Ltd | Health & social care | 2023 |
| KB Fast Ltd | Transport & logistics | 2024 |
| KBJ Developments Limited | Administrative & support | 2006 |
| KBR Newport Ltd | Hospitality | 2023 |
| KBS Cardiff Ltd | Hospitality | 2023 |
| KC Electronics Limited | Manufacturing | 1994 |
| KC Properties Bristol Ltd | Construction | 2019 |
| KC Resolution Ltd | Wholesale & retail | 2018 |
| KC Vending Ltd | Wholesale & retail | 2025 |
| KC4I Solutions Ltd | Information & communication | 2020 |
| KCC Sheetmetal Limited | Manufacturing | 2025 |
| Kccart Ltd | Wholesale & retail | 2025 |
| KCM Fabrications Limited | Manufacturing | 2026 |
| KCR Wealth Management Limited | Professional & scientific | 2016 |
| Kdams Consulting Ltd | Information & communication | 2026 |
| KDS Convenience Ltd | Wholesale & retail | 2026 |
| KDS Properties Ltd | Real estate | 2004 |
| KDT Offshore Services Ltd | Construction | 2014 |
| KED Shine Ltd | Administrative & support | 2019 |
| Keelrise Limited | Households | 1988 |
| Keen Building Ltd | Construction | 2021 |
| Keep the Faith Beauty Limited | Other services | 2013 |
| Keep the Faith Hairdresser Limited | Other services | 2016 |
| Keep the Faith Social Club Limited | Financial services | 2016 |
| Keep the Faith Tattoos Limited | Other services | 2016 |
| Keerat and Seerat Limited | Wholesale & retail | 2016 |
| Keetosales Limited | Wholesale & retail | 2025 |
| Keeyo Limited | Information & communication | 2014 |
| Keishas Creations Ltd | Wholesale & retail | 2026 |
| Keldaz Ltd | Professional & scientific | 2022 |
| Kelemen Building Contractors Ltd | Construction | 2026 |
| KELKIT61 Ltd | Hospitality | 2018 |
| Kelly East Wealth Management Ltd | Financial services | 2025 |
| Kelly Hancock Conveyancing Limited | Professional & scientific | 2025 |
| Kelly Mumford Ltd | Construction | 2019 |
| Kellyscakes Ltd | Wholesale & retail | 2025 |
| Kelseyshampers CYF | Wholesale & retail | 2025 |