| Kerr Family Property Holdings Ltd | Real estate | 2019 |
| Keshay Group Limited | Professional & scientific | 2024 |
| Keveral Holdings Limited | Professional & scientific | 2021 |
| Key Business Skills Limited | Education | 2003 |
| Key Creative Media Limited | Professional & scientific | 2012 |
| Key Sounds Ltd | Education | 2022 |
| KG Shaw Consulting Limited | Professional & scientific | 2017 |
| Kians Carpentry Ltd | Manufacturing | 2025 |
| Kidtropolis Ltd | Arts & recreation | 2016 |
| Kilsby Commercial Interiors Ltd | Manufacturing | 2015 |
| Kingfisher EAR Health Ltd | Health & social care | 2025 |
| Kingsbay Properties Ltd | Administrative & support | 2017 |
| Kingsley Terrace Flat Management Company Limited | Extraterritorial | 2010 |
| Kitts Consulting Ltd | Information & communication | 2019 |
| KJ Freight Limited | Transport & logistics | 2024 |
| KJB Training Limited | Education | 2024 |
| Klin Korea Ltd | Wholesale & retail | 2024 |
| Knibbs Leisure Group Ltd | Real estate | 2025 |
| Knightley Blinds Ltd | Wholesale & retail | 2016 |
| Knightsridge Limited | Professional & scientific | 2017 |
| Knowlywise Ltd | Professional & scientific | 2025 |
| Knox & Ross Roofing Ltd | Construction | 2025 |
| Kognity UK Ltd | Information & communication | 2017 |
| Kokovai Transport Driving Solution Ltd | Transport & logistics | 2011 |
| Kolak Transport Limited | Wholesale & retail | 2015 |
| Komodo Bikes Ltd | Manufacturing | 2021 |
| Kontrol Project Limited | Wholesale & retail | 2023 |
| Koonwah Limited | Wholesale & retail | 2026 |
| Kopp Facilities Management (KFM) Limited | Real estate | 2012 |
| Kr&Dec Co., Ltd | Professional & scientific | 2015 |
| Kreate Spaces Limited | Administrative & support | 2020 |
| Krimco Group Ltd | Hospitality | 2019 |
| KRO 1660 Limited | Professional & scientific | 2010 |
| Kroy 2011 Ltd | Financial services | 2014 |
| Krzysztof Lekso Ltd | Extraterritorial | 2026 |
| Kshd Holdings Ltd | Real estate | 2025 |
| KSJ Rentals Ltd | Real estate | 2015 |
| Kuni Coffee Ltd | Wholesale & retail | 2013 |
| Kurdish Barber Daventry Ltd | Other services | 2024 |
| Kweight Technology Ltd | Professional & scientific | 2008 |
| Kweku Consulting Limited | Information & communication | 2014 |
| L & D Country Dining Ltd | Hospitality | 2022 |
| L Wilson Paving Ltd | Construction | 2017 |
| L&N Homes Ltd | Real estate | 2023 |
| L&R Paving Ltd | Construction | 2025 |
| L.Black Ltd | Extraterritorial | 2018 |
| LAB8 Digital Ltd | Information & communication | 2026 |
| Laboratory Precision Limited | Manufacturing | 1986 |
| Lada Ltd | Transport & logistics | 2018 |
| Langley Investments Limited | Construction | 2016 |
| Langley Limited | Construction | 2023 |
| Langley Maintenance Limited | Construction | 2024 |
| Langley Regeneration Limited | Wholesale & retail | 2021 |
| Langley Renewables Limited | Wholesale & retail | 2021 |
| Langley Roofing Solutions Limited | Construction | 2021 |
| Langley Structures Limited | Construction | 2016 |
| Langley Training Services Limited | Education | 2020 |
| Langley UK Limited | Construction | 2008 |
| Langley UK Properties Limited | Real estate | 2013 |
| Langley Waterproofing Systems Limited | Construction | 1999 |
| Lannmarker Corporation Limited | Professional & scientific | 2014 |
| Lansa Pharma Group Ltd | Professional & scientific | 2013 |
| Lansford Properties Ltd | Real estate | 2025 |
| Lanterna Education Limited | Education | 2009 |
| Lara Macdonald Travel Ltd | Administrative & support | 2017 |
| Lashlake Developments Limited | Construction | 2016 |
| Lashlake Property Limited | Real estate | 1947 |
| Lawnhill Pet Crematorium Ltd | Other services | 2026 |
| LDG Construction Limited | Manufacturing | 2020 |
| Leadership Champions (UK) Ltd | Professional & scientific | 2011 |
| Leaf Marque Limited | Administrative & support | 2002 |
| Lean 4 Sales Ltd | Professional & scientific | 2016 |
| Learn. Inspire. Deliver. Consultancy Limited | Information & communication | 2024 |
| LEC Properties Holdings Limited | Financial services | 2012 |
| LEC Properties Limited | Real estate | 1999 |
| LEC Residential Limited | Real estate | 2001 |
| Leeding Holdings Ltd | Real estate | 2016 |
| Legacy Care Agency Ltd | Administrative & support | 2020 |
| Legacy Growers Ltd | Wholesale & retail | 2025 |
| Legacy Healthcare Group Ltd | Health & social care | 2024 |
| Legacy Outlaws Ltd | Arts & recreation | 2025 |
| Legacy Sport Academy Ltd | Education | 2023 |
| Leibling Property Limited | Households | 2022 |
| Lerigo Group Ltd | Manufacturing | 2007 |
| LES Olives Management Ltd | Administrative & support | 2018 |
| Lesa Clarke Limited | Administrative & support | 1980 |
| Let's Talk Ageing Limited | Professional & scientific | 2016 |
| Leverage Global Limited | Professional & scientific | 2015 |
| Levinte Ltd | Construction | 2019 |
| Lexshine Ltd | Wholesale & retail | 2018 |
| Leyla-F Limited | Administrative & support | 2017 |
| Licharz Ltd | Wholesale & retail | 1988 |
| Liersen UK Ltd | Professional & scientific | 2021 |
| Lighthorne Tree Care Ltd | Agriculture & fishing | 2025 |
| Linby Strand LLP | | 2007 |
| Lincoln Salam Ltd | Wholesale & retail | 2025 |
| Linear Accelerator Services Limited | Information & communication | 2014 |
| Link Marine Automation Co., Limited | Professional & scientific | 2017 |
| Linked and Loved Ltd | Wholesale & retail | 2026 |
| Linking Environment and Farming | Agriculture & fishing | 1995 |