| Lunar Labs Store Limited | Health & social care | 2026 |
| Lungu Truck Ltd | Transport & logistics | 2019 |
| Lust Interactive Ltd | Hospitality | 2022 |
| LUV Groundworks Ltd | Construction | 2014 |
| Luxdog Cornwall Ltd | Other services | 2017 |
| Luxury Price Ltd | Information & communication | 2019 |
| Luxury Resin Solutions Limited | Construction | 2022 |
| Luxushauser Ltd | Real estate | 2024 |
| LV & H Marketplace Ltd | Wholesale & retail | 2019 |
| LW Design Services Ltd | Professional & scientific | 2024 |
| Lwhiting Ltd | Construction | 2025 |
| Lxshan Retails (UK) Ltd | Wholesale & retail | 2024 |
| Lyliths Garden Services Ltd | Water & waste | 2024 |
| Lynnek Consulting Ltd | Administrative & support | 2016 |
| Lynnlea Ltd | Extraterritorial | 2022 |
| Lyte Signalling Services Ltd | Professional & scientific | 2018 |
| LYW Logistics Ltd | Transport & logistics | 2023 |
| M & J Connect Limited | Information & communication | 2025 |
| M & NT Ltd | Transport & logistics | 2026 |
| M & W Electrical Limited | Construction | 2012 |
| M a Heating Limited | Administrative & support | 2015 |
| M a Wood Limited | Administrative & support | 2012 |
| M and B Food Box Ltd | Hospitality | 2024 |
| M C Lets Limited | Real estate | 2018 |
| M C Lift Services Limited | Construction | 2024 |
| M Church Vehicle Services Limited | Wholesale & retail | 2015 |
| M D Optometry Limited | Health & social care | 2018 |
| M D Piercy Limited | Real estate | 2004 |
| M Dodge Holdings Limited | Financial services | 2022 |
| M E Dunmore Ltd | Professional & scientific | 2012 |
| M F Blount Ltd | Health & social care | 2022 |
| M J Wittering Plumbing & Heating Limited | Construction | 2007 |
| M K Scales Limited | Wholesale & retail | 2006 |
| M Knight Forestry and Civil Site Clearance Ltd | Agriculture & fishing | 2014 |
| M Minimarket Ltd | Wholesale & retail | 2024 |
| M Oxford Consulting Limited | Professional & scientific | 2017 |
| M R Harris Limited | Construction | 1997 |
| M Rozi Auto Ltd | Manufacturing | 2021 |
| M S N Teamwear Limited | Wholesale & retail | 2016 |
| M S Photography Limited | Administrative & support | 2011 |
| M W V Renovations Ltd | Professional & scientific | 2022 |
| M&D Painting and Decorating Service Limited | Construction | 2018 |
| M&F Building Maintenance Ltd | Construction | 2022 |
| M&I Catering Services Ltd | Construction | 2023 |
| M&P Pest Control Services Ltd | Administrative & support | 2025 |
| M&S Consultancy (Northampton) Limited | Administrative & support | 2017 |
| M&T's Bargains Limited | Wholesale & retail | 2014 |
| M'S Beauty Natural Wellness Limited | Other services | 2020 |
| M. a. Coales Family Butchers Limited | Wholesale & retail | 2014 |
| M. Gorrod Agencies Limited | Real estate | 1973 |
| M.A.D Landscapes Limited | Administrative & support | 2015 |
| M.C.F Cleaning Ltd | Administrative & support | 2020 |
| M.J. Adams (Holdings) Limited | Financial services | 2025 |
| M.J. Adams Limited | Real estate | 1977 |
| M.J.N Entertainment Limited | Arts & recreation | 2017 |
| M.M PMC Ltd | Health & social care | 2013 |
| M2K Supplies Ltd | Wholesale & retail | 2020 |
| M7EN Properties Ltd | Real estate | 2024 |
| Mackinnon Management Company Limited | Real estate | 2018 |
| Macready Engineering Ltd | Professional & scientific | 2019 |
| MAD Express Limited | Construction | 2012 |
| Maddock Care Ltd | Health & social care | 2025 |
| Maddock Homes Ltd | Real estate | 2021 |
| Maddock Investments 1 Ltd | Real estate | 2024 |
| Maddock Investments Ltd | Real estate | 2024 |
| Maddock Investments Winton Ltd | Households | 2025 |
| Madeira Entertainments Ltd | Arts & recreation | 2026 |
| Madyei Ltd | Public administration | 2023 |
| Magenta Lemon Ltd | Administrative & support | 2024 |
| Maggieto Ltd | Health & social care | 2015 |
| Magic Spedition Ltd | Transport & logistics | 2024 |
| Magma Trading Limited | Information & communication | 2006 |
| Magoos Construction Ltd | Construction | 2020 |
| Maha Food Limited | Hospitality | 2024 |
| Maia Communications Ltd | Administrative & support | 2009 |
| Mailfax Savings Ltd | Other services | 2022 |
| Main Legal Services (MLS) Limited | Professional & scientific | 2026 |
| Mainland Properties Limited | Real estate | 1997 |
| Mainly Metal Ltd | Wholesale & retail | 2013 |
| Mainstream Security Services Ltd | Administrative & support | 2020 |
| Major Keys Developments Ltd | Real estate | 2024 |
| Make Solutions Ltd | Manufacturing | 2020 |
| Make Time Marketing Ltd | Professional & scientific | 2026 |
| Makran International Trade Co Ltd | Wholesale & retail | 2025 |
| Malak Medics Limited | Health & social care | 2019 |
| Malast Ltd | Transport & logistics | 2014 |
| Malde Investments Limited | Real estate | 2022 |
| Malena Ltd | Construction | 2016 |
| Mambo Mutasa Ltd | Transport & logistics | 2025 |
| Manatee Design Studio Ltd | Information & communication | 2025 |
| Mancor House Limited | Real estate | 2021 |
| Mander Barrow PR Ltd | Information & communication | 2016 |
| Manesh Properties Limited | Real estate | 2018 |
| Mann Taxi Company Ltd | Transport & logistics | 2025 |
| Manna Treats Limited | Manufacturing | 2021 |
| Mannol Holdings Ltd | Other services | 2019 |
| Manoj Property Ltd | Real estate | 2023 |
| Manor Court (Wellingborough) Residents' Association Limited | Real estate | 1990 |
| Manor House Investments and Developments Limited | Real estate | 2017 |
| Mantra Services Limited | Professional & scientific | 2008 |