| Kiddoc Ltd | Health & social care | 2026 |
| Kiel Consultancy Limited | Information & communication | 2012 |
| Kingfisher Heating Ltd | Energy | 2020 |
| Kinshipworldwide Limited | Wholesale & retail | 2025 |
| Knight FOX Ltd | Real estate | 2011 |
| Kollynasy Ltd | Information & communication | 2025 |
| Korzmho Limited | Information & communication | 2016 |
| Korzwellz Limited | Information & communication | 2025 |
| Kravchuk Ltd | Other services | 2026 |
| KRB Consultant Limited | Professional & scientific | 2018 |
| KRISS19 Ltd | Administrative & support | 2018 |
| Kskat Limited | Real estate | 2024 |
| Kuntech Limited | Health & social care | 2018 |
| Kwamzmotors Ltd | Wholesale & retail | 2025 |
| LA Safety First Ltd | Construction | 2018 |
| Lamby Professional Services Limited | Professional & scientific | 2024 |
| Lasas FIX Limited | Construction | 2023 |
| Laurentiu Logistic Transport Limited | Transport & logistics | 2017 |
| Lavish Woof Limited | Wholesale & retail | 2021 |
| Layers Cakes Ltd | Wholesale & retail | 2026 |
| Leanwalls Ltd | Information & communication | 2022 |
| LEE Thurlow Consultancy Ltd | Information & communication | 2013 |
| Lela Project Management Ltd | Professional & scientific | 2005 |
| Lendai Limited | Information & communication | 2025 |
| Lethuthando Ltd | Health & social care | 2025 |
| Leti Ltd | Manufacturing | 2018 |
| LF Fabweld Ltd | Construction | 2018 |
| LGB Management Limited | Transport & logistics | 2012 |
| Limbas Services Ltd | Health & social care | 2023 |
| Linquiy Limited | Administrative & support | 2018 |
| Litchfield & Soundy Limited | Transport & logistics | 1901 |
| Little Ducklings Greenhithe Limited | Health & social care | 2024 |
| Living Word Conquerors Global Ltd | Other services | 2025 |
| Ljfg Services Ltd | Construction | 2018 |
| Local Plumbing and Bathroom Fitters Ltd | Construction | 2023 |
| LOK Renovations Ltd | Real estate | 2023 |
| Lolliescottage Limited | Manufacturing | 2025 |
| London Electrical Testing Ltd | Construction | 2025 |
| London-Bricks Developments Consult Limited | Administrative & support | 2018 |
| Lorian Consultants Limited | Professional & scientific | 2012 |
| Lotic Timepieces Ltd | Manufacturing | 2024 |
| Lotus Atelier Ltd | Wholesale & retail | 2018 |
| Loufred Ltd | Wholesale & retail | 2017 |
| LQ Designs (London) Ltd | Wholesale & retail | 2013 |
| Luca Designs Limited | Professional & scientific | 2025 |
| Luceat MED Ltd | Health & social care | 2022 |
| Lucinda Stuhllemmer Ltd | Other services | 2023 |
| Lucknow House Ltd | Wholesale & retail | 2022 |
| Lumiderm Ltd | Other services | 2026 |
| Lupa Global Trading Ltd | Professional & scientific | 2014 |
| Lustres Consulting Limited | Information & communication | 2022 |
| Luxciti Ltd | Professional & scientific | 2025 |
| Luxe Touch Services Ltd | Administrative & support | 2025 |
| Luxury Urbannests Ltd | Real estate | 2025 |
| Lynchtec Ltd | Professional & scientific | 2024 |
| M D Hussain Limited | Professional & scientific | 2012 |
| M.C. Swift Ltd. | Transport & logistics | 2008 |
| Macally Limited | Construction | 2021 |
| Macrotract Ltd | Professional & scientific | 2010 |
| MAD Play Ltd | Health & social care | 2019 |
| Maestro Minds Business Consultants Limited | Professional & scientific | 2023 |
| Magda Wright Ltd | Health & social care | 2019 |
| Mage Communications Limited | Administrative & support | 2013 |
| Main Bridge INT. Limited | Health & social care | 2015 |
| Major Empire Limited | Information & communication | 2024 |
| Makersoft Limited | Information & communication | 2010 |
| MAN in the Mirror UK CIC | Health & social care | 2025 |
| Marcfel Associates Limited | Professional & scientific | 2010 |
| Mareki Public House Ltd | Hospitality | 2025 |
| Markethousse Limited | Real estate | 2020 |
| Marnadi Trading Limited | Transport & logistics | 2022 |
| Matata Autos Ltd | Wholesale & retail | 2026 |
| MAW Entertainment Ltd | Arts & recreation | 2024 |
| MAX Building Solutions Ltd | Construction | 2019 |
| Maximum Air Services Limited | Construction | 2021 |
| Maya Hair & Aesthetics Ltd | Other services | 2026 |
| MBA Housing Limited | Real estate | 2023 |
| MBK Fleet Maintenance Ltd | Wholesale & retail | 2019 |
| MBN Carpentry Ltd | Manufacturing | 2020 |
| MBS Building Solutions Ltd | Construction | 2025 |
| MCC Solutions Limited | Administrative & support | 2026 |
| MCM Electrical Contractor Ltd | Construction | 2017 |
| MCM Sales and Marketing Limited | Professional & scientific | 2021 |
| MD Services South East Ltd | Construction | 2018 |
| Medplus Care Solutions Limited | Health & social care | 2015 |
| Merciport (UK) Ltd | Real estate | 2021 |
| Mesotherapy Clinic Ltd | Other services | 2020 |
| Messy Business Ltd | Administrative & support | 2026 |
| Mhofu FX Ltd | Other services | 2024 |
| Midi Resources Limited | Professional & scientific | 2017 |
| Mikelizbeth Limited | Real estate | 2022 |
| Miles Roofing & Building Ltd | Construction | 2024 |
| Millennial Properties Ltd | Real estate | 2020 |
| Millennium Flooring Ltd | Construction | 2025 |
| Minh ANH Builder Ltd | Construction | 2024 |
| MJC Driving Ltd | Transport & logistics | 2018 |
| Mk&Mk Limited | Manufacturing | 2025 |
| Mobnet Ltd | Information & communication | 2023 |
| Modern Lift Services Limited | Construction | 2011 |
| MOM Transport Ltd | Transport & logistics | 2020 |