| Luella Grey London Ltd | Manufacturing | 2019 |
| Lui.G Ltd | Manufacturing | 2018 |
| Luja Limited | Information & communication | 2024 |
| Lumo Intelligence Ltd | Information & communication | 2026 |
| Lunaverse Media Ltd | Wholesale & retail | 2025 |
| Luscombe Court (Number Two) Management Limited | Households | 1983 |
| Lushmart Limited | Wholesale & retail | 2025 |
| Lustre & Stone Limited | Manufacturing | 2026 |
| Lusty Glaze Developments Limited | Construction | 2013 |
| LUV Golf Ltd | Manufacturing | 2025 |
| LUX VIP Drive Ltd | Transport & logistics | 2023 |
| Luxe by Georgina Depay Ltd | Other services | 2024 |
| Luxecraft Jewellery Creations Limited | Manufacturing | 2025 |
| Luxtonvp Limited | Information & communication | 2010 |
| Luxuriant Suites Limited | Hospitality | 2024 |
| Luxury Carpet Club Ltd | Construction | 2026 |
| Luxury Clean Ltd | Administrative & support | 2019 |
| LVB Property Ltd | Real estate | 2020 |
| LWA Building & Maintenance Ltd | Construction | 2010 |
| Lynne Court (South Croydon) Limited | Real estate | 2007 |
| Lyriclab Ltd | Information & communication | 2024 |
| LYS Lighting Ltd | Wholesale & retail | 2025 |
| M & C Crown Ltd | Hospitality | 2025 |
| M & M Moran Mechanical & Electrical Ltd | Construction | 2016 |
| M & N Business Services Ltd. | Administrative & support | 2007 |
| M & S Executive and Chauffeur Ltd | Transport & logistics | 2021 |
| M & S Marketing Solutions Limited | Wholesale & retail | 2012 |
| M Adegoke Ltd | Health & social care | 2018 |
| M Cubed Management & PR Ltd. | Professional & scientific | 2015 |
| M W Floor Coverings Ltd | Construction | 2025 |
| M&M Brand Ltd | Professional & scientific | 2010 |
| M&M Decorating Ltd Ltd | Construction | 2017 |
| M&V Entertainment Limited | Hospitality | 2025 |
| M. a. Newsome & Co Limited | Professional & scientific | 2007 |
| M.Customs Limited | Wholesale & retail | 2024 |
| M.G.M. Property Consultants Limited | Extraterritorial | 2000 |
| M.J. Lawlor Carpentry Limited | Construction | 2017 |
| M.N.S. Building Team Ltd | Construction | 2026 |
| MA Temple Limited | Construction | 2005 |
| Maathiyosi Limited | Manufacturing | 2025 |
| Mabel Penge London Ltd | Hospitality | 2024 |
| MABROUKA25 Ltd | Other services | 2025 |
| MAC Design Ltd | Administrative & support | 2003 |
| MAC Mechanical PSV Limited | Wholesale & retail | 2023 |
| Macevoy-Troska Communications Limited | Construction | 1999 |
| Maclen Property Services Limited | Construction | 2012 |
| Mact Scaffolding Limited | Administrative & support | 2011 |
| Maculab Ltd | Information & communication | 2016 |
| MAD Dog Coffee Lounge (East Grinstead) Ltd | Hospitality | 2022 |
| MAD Properties Investment Ltd | Real estate | 2018 |
| Madalura London Ltd | Wholesale & retail | 2021 |
| Madam Martha Creative Agency Ltd | Professional & scientific | 2021 |
| Madebyculture Ltd | Professional & scientific | 2026 |
| Madello Consulting Limited | Information & communication | 2023 |
| Madesa Limited | Professional & scientific | 2010 |
| Madina Bakery & Restaurant Ltd | Hospitality | 2020 |
| Madison Global Solutions Ltd | Professional & scientific | 2016 |
| Maegridem Limited | Real estate | 2016 |
| Maestroworkout Ltd | Education | 2022 |
| Maggie's Group Limited | Manufacturing | 2019 |
| Magician Warriors Ltd | Information & communication | 2020 |
| Mahmut Property Management Limited | Real estate | 2012 |
| Maintenance.Ro Ltd | Construction | 2016 |
| Maiss Cosmetics Ltd | Other services | 2025 |
| MAJ Investments PL Ltd | Real estate | 2022 |
| MAK Socks and Fashion Ltd | Wholesale & retail | 2024 |
| Makas Grooming Ltd | Other services | 2024 |
| Makegood Property Group Ltd | Real estate | 2024 |
| Malg Ltd | Construction | 2012 |
| Maliha Boutique Ltd | Wholesale & retail | 2026 |
| MAM- Montenegro Ltd | Administrative & support | 2023 |
| Mameki Limited | Hospitality | 2019 |
| Mamilanji Ltd | Arts & recreation | 2020 |
| Management Holdings and Developments Limited | Administrative & support | 1975 |
| Manas Enterprises Ltd | Information & communication | 2012 |
| Mandela Bar & Kitchen Ltd | Hospitality | 2024 |
| Maniar Group Limited | Information & communication | 2026 |
| Manocap Advisory Ltd | Professional & scientific | 2016 |
| Manor Park Mews Limited | Construction | 2019 |
| Manor Place Management Company (1997) Limited | Real estate | 1996 |
| Manor Renovations Ltd | Construction | 2025 |
| Mansh Real Estate Ltd | Real estate | 2021 |
| Mapleleaf Close Residents' Company Limited | Extraterritorial | 2016 |
| Marbel ARK Ltd | Administrative & support | 2025 |
| Marble MEN Productions Limited | Information & communication | 2014 |
| Marc Parekh Events Limited | Hospitality | 2016 |
| Marc Parekh Limited | Professional & scientific | 2013 |
| Margaret Hayes Limited | Extraterritorial | 2025 |
| Marino Cafe Ltd | Hospitality | 2017 |
| Marinos Fish Shop Limited | Hospitality | 2018 |
| Mariya’S Nanny Services Limited | Health & social care | 2026 |
| Mark IT OFF Limited | Professional & scientific | 2008 |
| Mark Rixon Limited | Professional & scientific | 2018 |
| Mark Rochford Limited | Administrative & support | 2016 |
| Mark Tibbs Limited | Construction | 1997 |
| Markley Consultancy Limited | Information & communication | 2025 |
| Markley Services Limited | Information & communication | 2009 |
| Marouch Pastry and Cakes Ltd | Manufacturing | 2023 |
| Marpro Limited | Administrative & support | 2017 |
| Mars Sports CIC | Education | 2025 |