| LUX Travel Coin Ltd | Professional & scientific | 2023 |
| Luxe International Ltd | Information & communication | 2024 |
| Luxe Showband Ltd | Administrative & support | 2023 |
| Luxir Ltd | Professional & scientific | 2013 |
| Luxor Properties Limited | Extraterritorial | 1961 |
| Luxuriousbeautyboutique Ltd | Health & social care | 2015 |
| Luxury Chauffeur London Limited | Transport & logistics | 2025 |
| Luxury Clothing Ltd | Manufacturing | 2012 |
| Luxury Living Direct LLP | | 2011 |
| Luxury Villa Retreats Ltd | Other services | 2012 |
| Lydia Digital Ltd | Information & communication | 2022 |
| Lymm GIN Bar Ltd | Hospitality | 2019 |
| Lyra Advisory Limited | Professional & scientific | 2026 |
| Lyticas Technology Ltd | Information & communication | 2015 |
| M & G Fencing & Gardening Services Limited | Administrative & support | 2006 |
| M & G Property Management Limited | Real estate | 2010 |
| M & M Installations Limited | Construction | 2011 |
| M & T Andrews Limited | Construction | 2019 |
| M & W Media Limited | Information & communication | 2015 |
| M an P Supplies Ltd | | 2012 |
| M B Clinic Ltd | Health & social care | 2024 |
| M Beautique Ltd | Other services | 2025 |
| M C M Automarine Limited | Wholesale & retail | 2002 |
| M G Site Services Limited | Construction | 2024 |
| M H Merchant Ltd | Wholesale & retail | 2014 |
| M K Property Solution Limited | Construction | 2017 |
| M Kurian Associates Limited | Health & social care | 2015 |
| M P Flooring Solutions Limited | Construction | 2014 |
| M R Salmon Limited | Wholesale & retail | 2013 |
| M S Housing Limited | Hospitality | 2016 |
| M World Ltd | Administrative & support | 2016 |
| M&A Coffee Limited | Hospitality | 2016 |
| M&H Retail 2 Ltd | Hospitality | 2025 |
| M&H Retail Ltd | Hospitality | 2023 |
| M&K Ultra Ltd | Real estate | 2021 |
| M. Brown Demolition Limited | Construction | 1990 |
| M. Crane Services Limited | Construction | 2015 |
| M.C.Maintenance Limited | Other services | 1998 |
| M.G.B Sports Consultancy Ltd | Professional & scientific | 2019 |
| M.H. Freedman (Podiatrist) Limited | Health & social care | 2002 |
| M.R Accountants Ltd | Professional & scientific | 2016 |
| M.R.T Developments Limited | Real estate | 2018 |
| M.R.T Properties Limited | Real estate | 2025 |
| M.S.K. People Solutions Ltd | Professional & scientific | 2013 |
| M7 Electrical (London) Ltd | Construction | 2020 |
| M7 London Ltd | Professional & scientific | 2021 |
| Maam Property Management Ltd | Real estate | 2025 |
| Mabel Media Limited | Professional & scientific | 2024 |
| MAC Professional Services Ltd | Professional & scientific | 2013 |
| Macasade Property Lettings Limited | Real estate | 2021 |
| Machmain Limited | Information & communication | 1987 |
| Macies Ltd | Other services | 2023 |
| Macoda Professional Services Limited | Professional & scientific | 2014 |
| Macsow Ltd | Financial services | 2019 |
| Macticulous Limited | Information & communication | 2009 |
| MAD Homes Limited | Real estate | 2017 |
| Madalin&David Construction Limited | Construction | 2018 |
| Madana Developers Ltd | Construction | 2020 |
| Maddox Advisors (UK) Ltd | Financial services | 2013 |
| Madock Properties Ltd | Real estate | 2020 |
| Madwin Ltd | Real estate | 2022 |
| MAE Holdings Limited | Real estate | 2019 |
| Mafic Limited | Information & communication | 2018 |
| MAG Sparkle Cleaning Ltd | Administrative & support | 2021 |
| Magenta 8 Limited | Wholesale & retail | 2005 |
| Magni Fire (Projects) Limited | Administrative & support | 2015 |
| Magni Fire Limited | Manufacturing | 2013 |
| Magnum Developments Limited | Real estate | 1982 |
| Maiden Marc Associates Limited | Real estate | 2011 |
| Maison Bass Limited | Professional & scientific | 2018 |
| Maiya Holdings Ltd | Construction | 2023 |
| Majedi Holdings Limited | Construction | 2019 |
| Majestic Autos (UK) Limited | Wholesale & retail | 2011 |
| Majestic Care Management Ltd | Professional & scientific | 2020 |
| Majestic Company London Limited | Manufacturing | 2018 |
| Majestic Rock Catalogue Limited | Administrative & support | 2005 |
| Major Mobile Inc LLP | | 2020 |
| MAK Accountants Limited | Professional & scientific | 2015 |
| Make Believe Media & Entertainment Ltd | Professional & scientific | 2020 |
| Makesave Limited | Extraterritorial | 1992 |
| Makkah Food Stores Limited | Wholesale & retail | 2020 |
| Maks 22 Ltd | Construction | 2022 |
| Mala Business Solutions Limited | Professional & scientific | 2016 |
| Mala Limited | Hospitality | 2021 |
| Malafame Limited | Administrative & support | 1991 |
| Malcolm Care Associates Ltd | Health & social care | 2016 |
| Malice Ltd | Wholesale & retail | 2025 |
| Maloch Ltd | Real estate | 2019 |
| Malone Workshop Limited | Administrative & support | 2015 |
| Mama MIA Kettering Ltd | Hospitality | 2024 |
| Mamalujo Limited | Information & communication | 2026 |
| MAN With a Van (Epping) Limited | Transport & logistics | 2003 |
| Manaff Ltd | Information & communication | 2024 |
| Mandala 2016 Ltd | Public administration | 2016 |
| Mandala Service Center London Ltd | Wholesale & retail | 2018 |
| Mandir Property Ltd | Real estate | 2022 |
| Mandy the Mouth Properties Limited | Real estate | 2004 |
| Mangan Solutions Limited | Professional & scientific | 2015 |
| Mangrove Global Limited | Wholesale & retail | 2013 |
| Mani Kohli's UK Limited | Real estate | 2005 |