| Kenzi Security & Technology Ltd | Information & communication | 2023 |
| Kenzlex Recovery Ltd | Wholesale & retail | 2025 |
| Kerrigan Logistic Services Ltd | Transport & logistics | 2019 |
| Kest Services Limited | Manufacturing | 2023 |
| Kestrel Windows & Conservatories Limited | Construction | 2001 |
| Keyhirst Limited | Information & communication | 2018 |
| Keymore Limited | Real estate | 2021 |
| Kfip Limited | Professional & scientific | 2012 |
| KGR Project Controls Limited | Professional & scientific | 2012 |
| Khbd Limited | Households | 2012 |
| Khbd Property Management Ltd | Households | 2020 |
| Ki-Senteret Oslo Limited | Extraterritorial | 2010 |
| Kids Love Travel CIC | Hospitality | 2025 |
| Kill the Lights Limited | Arts & recreation | 2019 |
| Kilo Delta Design Ltd | Information & communication | 2018 |
| Kinder Company Holdings Ltd | Financial services | 2022 |
| King Access Hire Ltd | Administrative & support | 2025 |
| Kingfisher Sales & Marketing LLP | | 2014 |
| Kings Motors (Bridgend) Ltd | Wholesale & retail | 2025 |
| Kings Services Limited | Transport & logistics | 2025 |
| Kingstong Engineering Ltd | Administrative & support | 2016 |
| Kirkmain Limited | Extraterritorial | 2026 |
| Kirkpark Limited | Extraterritorial | 2025 |
| Kirkward Limited | Extraterritorial | 2025 |
| Kirsty O'Connell Limited | Real estate | 2025 |
| KJ Papworth Tour Services Limited | Professional & scientific | 2011 |
| KJE Auto Driver Training Ltd | Education | 2025 |
| Kjellgren Investment Limited | Extraterritorial | 2010 |
| KKK Holdings Limited | Financial services | 2026 |
| Klintealis Advisory Ltd | Professional & scientific | 2025 |
| KM Aesthetics (South Wales) Limited | Other services | 2019 |
| Knight Green Solutions Limited | Professional & scientific | 2022 |
| Knightsbridge Properties (2014) Limited | Real estate | 2014 |
| Knightsbridge Property Development Corporation (UK) Limited | Real estate | 1996 |
| KNS Contracting Ltd | Construction | 2019 |
| Kobu Retails Ltd | Wholesale & retail | 2025 |
| Kongs Gym Bridgend Ltd | Wholesale & retail | 2012 |
| Kongs Gym Ltd | Arts & recreation | 2018 |
| Konieczka Ltd. | Information & communication | 2016 |
| Kontrast Recovery Limited | Arts & recreation | 2026 |
| Kontrolmek Ltd | Manufacturing | 2021 |
| Kontroltek Holdings Limited | Manufacturing | 2020 |
| Kontroltek INT Ltd | Manufacturing | 2012 |
| Kontroltek Limited | Manufacturing | 2011 |
| Kontroltek Midlands Limited | Manufacturing | 2014 |
| Korale Limited | Administrative & support | 2002 |
| Koremade Ltd | Agriculture & fishing | 2025 |
| Korona Kitchens Limited | Manufacturing | 2015 |
| Kostic Development Company Limited | Construction | 1976 |
| Kostic Investment Company Limited | Construction | 2010 |
| Kostic Property Company Limited | Construction | 2010 |
| KP CH4 Limited | Construction | 2023 |
| KPC Youth & Community | Education | 2007 |
| KPD Regenerations Ltd | Real estate | 2023 |
| Kris Hicks Electrical Limited | Construction | 2023 |
| Krsg Property Ltd | Real estate | 2020 |
| Krybe Limited | Information & communication | 2024 |
| KT Abide Ltd | Wholesale & retail | 2021 |
| KT Consultancy (Bridgend) Limited | Professional & scientific | 2025 |
| KTF Gifts Bridgend Ltd | Wholesale & retail | 2024 |
| KTF Gifts Ltd | Wholesale & retail | 2023 |
| KTP Properties Ltd | Real estate | 2019 |
| Kuma Punch Productions Ltd | Wholesale & retail | 2024 |
| Kurz Ltd | Wholesale & retail | 2023 |
| Kusuma Limited | Health & social care | 2011 |
| Kvld Investments Limited | Professional & scientific | 2018 |
| KW Group (2022) Ltd | Manufacturing | 2022 |
| Kwan Anaesthetic Services Limited | Other services | 1995 |
| Kwik Cabs Taxis Ltd | Transport & logistics | 2025 |
| Kwik Leasing Ltd | Transport & logistics | 2025 |
| Kwservicesjf Ltd | Other services | 2026 |
| Kymco UK Ltd | Wholesale & retail | 2008 |
| L & F Recycling Machines Ltd | Real estate | 2011 |
| L & K Richardson(Investments)Limited | Construction | 1965 |
| L & M Proprietas Ltd | Real estate | 2021 |
| L & R Evans Construction Ltd | Construction | 2019 |
| L & S Building (Wales) Ltd | Construction | 2014 |
| L and T Dentures Laboratory Limited | Health & social care | 2008 |
| L Ormond Carpentry Ltd | Construction | 2026 |
| L R Doughty Ltd | Professional & scientific | 2021 |
| L T D Developments Ltd | Construction | 2023 |
| L&J Propety Maintenance and Wasteman Removal Services Limited | Water & waste | 2017 |
| L'Ultimo Limited | Hospitality | 2020 |
| L.D Transport Consultants Ltd | Professional & scientific | 2022 |
| L.J Environmental Waste Management Limited | Water & waste | 2023 |
| L.M.G. Solutions Limited | Professional & scientific | 1999 |
| LA Cocina Tapas Ltd | Hospitality | 2015 |
| LA Marketing & Automation Limited | Information & communication | 2014 |
| LA Mazure Ltd | Real estate | 2004 |
| LA Railway Ltd | Hospitality | 2022 |
| LAB23 Ltd | Professional & scientific | 2024 |
| Labanud Property Limited | Real estate | 2009 |
| Lagom Consultants Limited | Professional & scientific | 2024 |
| Lakebest Limited | Extraterritorial | 2026 |
| Lakecote Limited | Extraterritorial | 2025 |
| Lakshitha Ltd | Administrative & support | 2022 |
| Laleston Cars Limited | Transport & logistics | 1995 |
| Laleston Property Limited | Construction | 2025 |
| LAM LAM Chinese Ltd | Hospitality | 2026 |
| Lamados Builders Limited | Construction | 2025 |