| Kinetic Kids CIC | Education | 2023 |
| Kingdom Living Limited | Professional & scientific | 2019 |
| Kingfisher Construction Ltd | Construction | 2024 |
| Kingfisher Installations Limited | Administrative & support | 2009 |
| Kingsley Foods Limited | Wholesale & retail | 1993 |
| Kingswood Chase Consulting Ltd | Professional & scientific | 2012 |
| Kingswood Construction Developments Ltd | Construction | 2018 |
| Kingswood Housing Limited | Real estate | 2011 |
| Kiosk TEN Limited | Hospitality | 2017 |
| Kira Gilbert Ltd | Professional & scientific | 2025 |
| Kirbys Direct Ltd | Administrative & support | 2023 |
| Kiss Mwah Ltd | Wholesale & retail | 2017 |
| Kit's Trading Co Limited | Wholesale & retail | 2011 |
| Kitson Engineering Ltd. | Transport & logistics | 1993 |
| Kitsonclarke Properties Ltd | Real estate | 2025 |
| KJ Cleaning Limited | Water & waste | 2003 |
| KJG Cloud Consulting Ltd | Information & communication | 2022 |
| KJH Bookkeeping Ltd | Professional & scientific | 2019 |
| KL Detailing Autos Limited | Administrative & support | 2025 |
| Klarok Accommodation Ltd | Real estate | 2019 |
| Klarok Investments Ltd | Real estate | 2024 |
| Kleen Solar Limited | Extraterritorial | 2025 |
| KMD Business Development Ltd | Professional & scientific | 2012 |
| KNA Advisory Ltd | Professional & scientific | 2024 |
| Knatchbull Investment Company Limited | Real estate | 1963 |
| Knights Storage Ltd | Transport & logistics | 2020 |
| Knightsbridge Perfume Limited | Professional & scientific | 2024 |
| Knitting Media Limited | Professional & scientific | 2021 |
| Knopp Group Limited | Construction | 2019 |
| Know & Insure Ltd | Information & communication | 2016 |
| Know Your Success Ltd | Professional & scientific | 2021 |
| Koel Holding Ltd | Administrative & support | 2025 |
| Koelington Group Ltd | Construction | 2021 |
| Koelington Media Ltd | Professional & scientific | 2024 |
| Koller UK Immobilien Limited | Real estate | 2010 |
| Komberg Properties Ltd | Real estate | 2024 |
| Kotorri Limited | Other services | 2024 |
| Kouve Decor Limited | Construction | 2024 |
| Kova Clinic Limited | Other services | 2026 |
| KP (Essex) Ltd | Extraterritorial | 2018 |
| KP (Hawthorne) Ltd | Extraterritorial | 2019 |
| KP Accountancy Limited | Professional & scientific | 2008 |
| KP Business Group Ltd | Professional & scientific | 2025 |
| KP Capital Ltd | Financial services | 2025 |
| KPD Windows and Doors Limited | Construction | 2022 |
| Krhys Properties Limited | Real estate | 2024 |
| Kron Car Wash Limited | Administrative & support | 2024 |
| Krona Homes Ltd | Construction | 2017 |
| Krska Trading Ltd | Wholesale & retail | 2023 |
| KSC Sports Management Group Ltd | Arts & recreation | 2017 |
| KUK Dynamics Limited | Manufacturing | 2020 |
| Kushdy M&E Ltd | Other services | 2023 |
| KV2 Audio Europe Limited | Wholesale & retail | 2002 |
| KVP Advisory Ltd | Professional & scientific | 2023 |
| KVT Properties Ltd | Real estate | 2021 |
| Kwester Ltd | Real estate | 2025 |
| KWR Consulting Limited | Professional & scientific | 2022 |
| KY Harkins Counselling Services Ltd | Professional & scientific | 2024 |
| Ky'Cut Wilson Limited | Other services | 2014 |
| Kyla & Co Enterprises Ltd | Wholesale & retail | 2023 |
| L & D Electrical Contractors Limited | Construction | 2010 |
| L & I Consultancy Ltd | Professional & scientific | 2019 |
| L & J Hall Digging Services Limited | Construction | 2007 |
| L & J Roofing Ltd | Construction | 2019 |
| L & M Lowestoft Limited | Wholesale & retail | 2024 |
| L & P Mortgage & Financial Services Limited | Financial services | 2002 |
| L C Spencer Building Ltd | Administrative & support | 2021 |
| L J C Project Management Ltd | Administrative & support | 2013 |
| L J Law Limited | Construction | 2023 |
| L K Rail Limited | Construction | 2013 |
| L P Print Solutions Ltd | Manufacturing | 2008 |
| L S a Management Ltd | Professional & scientific | 2019 |
| L T B Builders Ltd | Construction | 2025 |
| L T L Construction Ltd | Construction | 2017 |
| L&G London Uniforms U.K. Limited | Manufacturing | 2012 |
| L&H Investment Group Limited | Financial services | 2025 |
| L&M Debt Recovery Ltd | Professional & scientific | 2026 |
| L-O-S Calisthenics Ltd | Arts & recreation | 2022 |
| L.H Admin Services Limited | Administrative & support | 2024 |
| L.J. Pratley & Partners Limited | Construction | 2008 |
| L.O.S. Cleaning Ltd | Administrative & support | 2025 |
| LA Fabbrica Ltd | Hospitality | 2023 |
| LA Laigne Consultancy Limited | Information & communication | 1998 |
| LA Plata Grove Management Company Limited | Real estate | 2022 |
| LAB EN SPV 01 Limited | Construction | 2024 |
| Labco Consultancy Services Limited | Professional & scientific | 2003 |
| Lady Mcadden Breast Cancer Trust | Health & social care | 1997 |
| Ladybird Management Services (UK) Ltd | Professional & scientific | 2024 |
| Lafferty Medical Supplies Limited | Health & social care | 2012 |
| Laisim Ltd | Professional & scientific | 2022 |
| Laissez Faire Club Limited | Information & communication | 2012 |
| Lakes Shipping Limited | Professional & scientific | 2026 |
| Lakestone Electrical Ltd | Construction | 2021 |
| Lakestone Property Management Ltd | Real estate | 2021 |
| Laks Investment Ltd | Real estate | 2013 |
| Lala Lagree Ltd | Arts & recreation | 2025 |
| Lalis Limited | Wholesale & retail | 2007 |
| Lamaza Solutions Limited | Administrative & support | 2024 |
| Lambert Media Ltd | Professional & scientific | 2025 |
| LAN Transport Ltd | Transport & logistics | 2025 |