| Krishkul Ltd | Wholesale & retail | 2011 |
| Krispy Katch Limited | Hospitality | 2024 |
| Kristle Rose Limited | Arts & recreation | 2024 |
| Krux Music Publishing Ltd | Administrative & support | 2021 |
| KRYTON4 Ltd | Professional & scientific | 2017 |
| KSM Consultants Limited | Professional & scientific | 2019 |
| KSS Fast Food Ltd | Hospitality | 2019 |
| KTB Contractors Limited | Other services | 2016 |
| KTB Kids Ltd | Health & social care | 2013 |
| Ktmj Assets Ltd | Real estate | 2024 |
| Kt’S Tennis Ltd | Education | 2022 |
| KU Consultations Ltd | Professional & scientific | 2022 |
| Kugaforce Ltd | Financial services | 2024 |
| Kuhi Estates Ltd | Real estate | 2024 |
| Kuka Coffee Ltd | Extraterritorial | 2016 |
| Kumar Food & Wine Ltd | Wholesale & retail | 2024 |
| Kumon Erith Ltd | Education | 2024 |
| Kunle Zenith Limited | Wholesale & retail | 2026 |
| KVM Cleaning Services Ltd | Administrative & support | 2017 |
| KVN Tech Ltd | Wholesale & retail | 2025 |
| Kwality Ltd | Wholesale & retail | 2019 |
| Kwamash Health Care Services Limited | Health & social care | 2018 |
| Kwik Phix Services Ltd | Other services | 2025 |
| Kwisdom Consulting Limited | Administrative & support | 2020 |
| Kwisdom Holdings Limited | Administrative & support | 2012 |
| Kwisdom Properties Limited | Real estate | 2012 |
| Kyalami Property Developments Limited | Real estate | 2006 |
| Kyberian Consulting Ltd | Administrative & support | 2024 |
| Kylefield Limited | Real estate | 1974 |
| Kymax Building Facilities Ltd | Construction | 2011 |
| Kymzus Media Corporation Ltd | Professional & scientific | 2011 |
| KYN Fitness Group Ltd | Arts & recreation | 2025 |
| KZ Winstanley Ltd | Professional & scientific | 2026 |
| L & D Commercials Ltd | Wholesale & retail | 2015 |
| L G R Commercials Limited | Wholesale & retail | 2012 |
| L G Rogers Master Carpenter Limited | Construction | 2016 |
| L Mills Nursery Limited | Wholesale & retail | 2017 |
| L Mills Trading Limited | Wholesale & retail | 2016 |
| L Ruberto Foods Ltd | Hospitality | 2025 |
| L&A Autos Ltd | Wholesale & retail | 2011 |
| L&C Platinum Property Ltd | Real estate | 2019 |
| L.Bain & Co.Limited | Transport & logistics | 1965 |
| L.C Auto Techs Ltd | Wholesale & retail | 2025 |
| L.C.T. Engineering Limited | Professional & scientific | 2014 |
| L.D.L.Cousins Electrical Engineering. Limited | Information & communication | 2014 |
| L.E. Delights Limited | Extraterritorial | 1989 |
| L.M. Cleaning Limited | Administrative & support | 2003 |
| L.M.S. Limited | Manufacturing | 1979 |
| L.Wallacee Limited | Wholesale & retail | 2025 |
| LA Bello Beauty Limited | Wholesale & retail | 2018 |
| LA Mortgage Solutions Limited | Financial services | 2025 |
| LAC Automotive Ltd | Wholesale & retail | 2024 |
| Ladygrove Specialist Ltd | Health & social care | 2014 |
| Lagc Limited | Information & communication | 2025 |
| Lahti Management Limited | Administrative & support | 2001 |
| LAI Wellness Ltd | Health & social care | 2025 |
| Laila Duggan Consulting Limited | Professional & scientific | 2025 |
| Laing Construction Limited | Construction | 1995 |
| Laing Engineering Limited | Construction | 1981 |
| Laing Limited | Construction | 1998 |
| Laing O'Rourke Delivery Limited | Construction | 2001 |
| Laing O'Rourke Holdings Limited | Construction | 2001 |
| Laing O'Rourke Infrastructure Limited | Construction | 2001 |
| Laing O'Rourke Midlands Limited | Construction | 2001 |
| Laing O'Rourke PLC. | Construction | 2001 |
| Laing O'Rourke Scotland Limited | Construction | 2001 |
| Laing O'Rourke Services Limited | Construction | 2002 |
| Laing O'Rourke Utilities Limited | Construction | 2001 |
| Laing O'Rourke Wales & West Limited | Construction | 2001 |
| Laith International Ltd | Information & communication | 2022 |
| Lakebridge 2008 Limited | Real estate | 2008 |
| Lakeh’S Ltd | Health & social care | 2023 |
| Lakes Dominos Ltd | Hospitality | 2024 |
| Laks Properties Ltd | Real estate | 2024 |
| Lalabazar Union Education Trust (UK 2009) Limited | Education | 2018 |
| Lalenz Ltd | Professional & scientific | 2024 |
| Lamb Investments Limited | Real estate | 2016 |
| Lambert Close Freeholders Limited | Real estate | 2023 |
| Lambourne Close (Farningham) Ltd | Households | 2019 |
| Lambournes Commercial Services Ltd | Wholesale & retail | 2022 |
| Lamm (UK) Limited | Construction | 2004 |
| Lamprell Roofing Ltd | Construction | 2014 |
| Lampsel Limited | Real estate | 2019 |
| Lamubi Limited | Administrative & support | 2016 |
| Lanai Lifestyle Ltd | Administrative & support | 2023 |
| Land Investment & Development Company Limited | Real estate | 1961 |
| Landestate.Co.Uk Limited | Real estate | 2006 |
| Landgate (New Homes) Limited | Real estate | 2005 |
| Lane Luxe London Ltd | Manufacturing | 2024 |
| Lanelamultipleventures Limited | Health & social care | 2021 |
| Lanes to Success Limited | Education | 2022 |
| Lang Air Ltd | Construction | 2022 |
| Langford Collectibles Ltd | Wholesale & retail | 2025 |
| Lanh Professionals LLP | | 2016 |
| Lanmark Limited | Information & communication | 1994 |
| Lanre Badmus Ltd | Information & communication | 2018 |
| Lanre Mondo Limited | Health & social care | 2016 |
| Lansdowne 628 Ltd | Administrative & support | 2017 |
| Lansgrove Limited | Construction | 2014 |
| Lara Star Ltd | Health & social care | 2016 |