| LSW Sales Ltd | Wholesale & retail | 2025 |
| LT Ecommerce Ltd | Wholesale & retail | 2025 |
| LTR Services & Solutions Ltd | Wholesale & retail | 2023 |
| Lubrin Limited | Professional & scientific | 2021 |
| Luca Spedition Ltd | Transport & logistics | 2019 |
| Lucciola Bidco Limited | Financial services | 2025 |
| Lucciola Midco Limited | Financial services | 2025 |
| Lucciola Topco Limited | Financial services | 2025 |
| Lucky 11 Detailing Limited | Wholesale & retail | 2022 |
| Lucky Rabbit Crawley Limited | Hospitality | 2025 |
| Lucy a Poleykett Limited | Professional & scientific | 2018 |
| Luhar & Sons Industry Ltd | Wholesale & retail | 2025 |
| Luhmann Dublin 2 Limited | Real estate | 2016 |
| Luke Masters Ltd | Other services | 2024 |
| Lulo & Co. Property Management Ltd | Hospitality | 2025 |
| Lulu's Luxury Hair Lounge Ltd | Other services | 2026 |
| Lumi Lise Ltd | Information & communication | 2020 |
| Lumina Trace Ltd | Information & communication | 2024 |
| Luminark Ventures Limited | Wholesale & retail | 2025 |
| Luminary Management Recruitment Ltd | Other services | 2019 |
| Lunar Ice Ltd | Wholesale & retail | 2021 |
| Lunar Leapyear Limited | Information & communication | 2025 |
| LUO Women UK Ltd | Professional & scientific | 2020 |
| Lusignea Accounting & Consulting Ltd | Professional & scientific | 2026 |
| Lustra Cleans Limited | Administrative & support | 2025 |
| Lutterworth Country Park Limited | Real estate | 2020 |
| Luwuliza Limited | Health & social care | 2020 |
| LUX Shutters Ltd | Administrative & support | 2017 |
| Luxe Beautybar Ltd | Other services | 2024 |
| Lycan Group Ltd | Wholesale & retail | 2018 |
| Lychee Rose Limited | Professional & scientific | 2023 |
| Lynx Precise Care Ltd | Health & social care | 2025 |
| Lyonn Ltd | Construction | 2020 |
| M & V Maintenance Ltd | Other services | 2018 |
| M a Contractors (UK) Limited | Construction | 2012 |
| M a Flooring & Carpets Ltd | Construction | 2012 |
| M and S Tobacco Ltd | Wholesale & retail | 2013 |
| M Angelova Limited | Arts & recreation | 2024 |
| M Bray Property Ltd | Real estate | 2017 |
| M D Cotterell Fabrications Limited | Manufacturing | 2017 |
| M D Services Group Limited | Construction | 2021 |
| M George Corporation Ltd | Professional & scientific | 2021 |
| M Istrefi Ltd | Administrative & support | 2023 |
| M J Autos (Surrey) Limited | Wholesale & retail | 2015 |
| M J C Building & Decorating Services Ltd | Construction | 2018 |
| M King Groundworks Limited | Construction | 2003 |
| M W Botha Limited | Health & social care | 2009 |
| M&B Total Property Solutions Ltd | Households | 2026 |
| M&H Co Trading Ltd | Hospitality | 2023 |
| M&H Environmental Ltd | Extraterritorial | 2023 |
| M&K Finance Limited | Administrative & support | 2012 |
| M&K Groundworks Ltd | Construction | 2019 |
| M&M Diamond Properties Ltd | Real estate | 2025 |
| M&M Group of Company Limited | Professional & scientific | 2025 |
| M&S Services Limited | Real estate | 2021 |
| M.A Beauty & Aesthetics Ltd | Wholesale & retail | 2019 |
| M.A. Bookkeeping Ltd | Professional & scientific | 2013 |
| M.I.L. Services Limited | Manufacturing | 2001 |
| M.Zychowicz Transport Ltd | Administrative & support | 2016 |
| M1 Fencing Limited | Construction | 2014 |
| MA Assessors Ltd | Wholesale & retail | 2024 |
| MA Safety Consultants Ltd | Professional & scientific | 2024 |
| MA. MED Limited | Health & social care | 2015 |
| MAA UMA Limited | Wholesale & retail | 2024 |
| Maata Ltd | Health & social care | 2022 |
| MAC Group Ventures Ltd | Information & communication | 2023 |
| Maca Projects Limited | Construction | 2009 |
| Macbuild Homes Ltd | Construction | 2011 |
| Macgorman Associates Limited | Information & communication | 2004 |
| Mach 1 Services Ltd | Manufacturing | 2021 |
| Machimbis Limited | Health & social care | 2014 |
| Machucaengineering Ltd | Wholesale & retail | 2015 |
| Mack Tours LK Limited | Administrative & support | 2025 |
| Mackay Marine UK Ltd | Wholesale & retail | 2005 |
| Macl Holdings Limited | Financial services | 2020 |
| Maczas for YOU Ltd | Administrative & support | 2025 |
| Madalan Security Limited | Administrative & support | 2017 |
| Madhavy Ltd | Wholesale & retail | 2016 |
| MADHAVY77 Limited | Wholesale & retail | 2024 |
| Madigan Homes Ltd | Real estate | 2024 |
| Madison James Installation Services Ltd | Construction | 2014 |
| Maedeh's Food Ltd | Hospitality | 2022 |
| Magfit Ltd | Manufacturing | 2022 |
| Magic 4 Events Limited | Arts & recreation | 2015 |
| Magire Investments | Other services | 2018 |
| Magnolia Care Ltd | Health & social care | 2013 |
| Magnum Consulting and Management Services Ltd | Real estate | 2017 |
| Magnusdata Limited | Information & communication | 2023 |
| Magus Group Limited | Financial services | 2009 |
| Magus Private Wealth Limited | Financial services | 1998 |
| Magus Professional Partners LLP | | 2009 |
| Magus TAO Limited | Financial services | 2014 |
| Magys Corporation Ltd | Wholesale & retail | 2022 |
| Maha Kall Ltd | Wholesale & retail | 2026 |
| Mahavir Consultancy Limited | Information & communication | 2012 |
| Maheen (Crawley) Ltd | Other services | 2020 |
| Mahmoodn Ltd | Health & social care | 2024 |
| Maidenbower Park (Mpcc) Community Interest Company | Health & social care | 2016 |
| Maidenbower Village Services Ltd | Wholesale & retail | 2019 |
| Maidstone Dental Care Limited | Health & social care | 2007 |