| LUX Class Ltd | Transport & logistics | 2016 |
| Luxe Corporation Ltd | Wholesale & retail | 2011 |
| Luxe Home Renovations Ltd | Construction | 2021 |
| LV Recycling Clothes Ltd | Other services | 2018 |
| Lyfe Global Limited | Professional & scientific | 2017 |
| Lynchmob Productions Ltd | Information & communication | 1997 |
| M & I Flooring Limited | Wholesale & retail | 1999 |
| M & N Windows Ltd | Wholesale & retail | 2010 |
| M C International Links Limited | Professional & scientific | 2009 |
| M C Services Links Limited | Professional & scientific | 2014 |
| M Levy Ltd | Health & social care | 2023 |
| M T J R Property Management Ltd | Construction | 2017 |
| M&I Construction Limited | Wholesale & retail | 2025 |
| M&I Supplies Ltd | Construction | 2018 |
| M&S Housing (North West) Ltd | Real estate | 2025 |
| M.B. Car Hire Limited | Administrative & support | 2016 |
| M.M.J. Assistance Limited | Wholesale & retail | 2020 |
| Macmoor Associates Limited | Administrative & support | 2003 |
| Mado Construction and SON Limited | Construction | 2022 |
| Magics Electrical Services Limited | Construction | 2004 |
| Mainhouse London Ltd | Real estate | 2023 |
| Maistor Ltd | Construction | 2013 |
| Mandees Properties Ltd | Real estate | 2016 |
| Manor Build Limited | Real estate | 2021 |
| Marcus Paul Kitchens Limited | Manufacturing | 2001 |
| Mare Street Ltd | Construction | 2021 |
| Marilu Marada Limited | Manufacturing | 2020 |
| Marimed Agencies (UK) Limited | Transport & logistics | 1984 |
| Marimed Shipping Limited | Transport & logistics | 1983 |
| Marine Master Group Ltd | Transport & logistics | 2022 |
| Marine Shipmanagement Ltd | Transport & logistics | 2023 |
| Mariposa Solutions Limited | Professional & scientific | 2011 |
| Marks Commercials Limited | Other services | 2013 |
| Martin Wilde Windows Limited | Construction | 2003 |
| Mason Kiely Media Ltd | Other services | 2023 |
| Matanovic Group Ltd | Professional & scientific | 2024 |
| Matthew Emvin Taylor Cinematographer Ltd | Information & communication | 2022 |
| Matz Consulting Limited | Information & communication | 2013 |
| MAW Safeguarding Limited | Health & social care | 2017 |
| Maxant Consulting Limited | Professional & scientific | 2017 |
| MAY of London Limited | Wholesale & retail | 1967 |
| Maya Transport Logistics Ltd | Wholesale & retail | 2020 |
| Mayn Services Ltd | Construction | 2026 |
| Mazir UK Ltd | Real estate | 2021 |
| MBM Academy Ltd | Other services | 2024 |
| Mccoy Pearce Limited | Professional & scientific | 2013 |
| Mcomms Media Ltd | Information & communication | 2026 |
| MD Constructions (London) Ltd | Construction | 2014 |
| MDA Surveying Services Limited | Professional & scientific | 2006 |
| Mdjpropertygroup Limited | Households | 2021 |
| ME Housing (North West) Ltd | Real estate | 2025 |
| Mediated Dispute Solutions Limited | Professional & scientific | 2014 |
| MEM Consulting Ltd | Professional & scientific | 2023 |
| MEP Pro Ltd | Administrative & support | 2016 |
| Meridius Electrical Ltd | Construction | 2021 |
| Merilyn Films Ltd | Professional & scientific | 2018 |
| Metagrafix Limited | Professional & scientific | 2022 |
| Metals Consulting International Limited | Professional & scientific | 2003 |
| Metrium Service Limited | Construction | 2025 |
| MG Hair & Make UP Limited | Other services | 2017 |
| MH Investigative Consultants Ltd | Financial services | 2021 |
| Micon HTI Limited | Professional & scientific | 2019 |
| Mike Lewis Management Limited | Real estate | 1987 |
| Milagros Fresh Limited | Wholesale & retail | 2026 |
| Milford Accounting Ltd | Administrative & support | 2018 |
| Millan House Limited | Real estate | 2022 |
| Miller and Bull Ltd | Professional & scientific | 2020 |
| Mini Ballers Soccer School Ltd | Administrative & support | 2017 |
| Mini Sports Stars Ltd | Education | 2023 |
| Mistagripsta Ltd | Information & communication | 2020 |
| Misure Housing North West Ltd | Real estate | 2025 |
| Mjweatherley Consulting Ltd | Professional & scientific | 2024 |
| MK Baltic Trade Ltd | Wholesale & retail | 2025 |
| Mmframe Ltd | Professional & scientific | 2013 |
| MNM Property Partners Limited | Real estate | 2023 |
| Modern Formwork Limited | Real estate | 2024 |
| Moist Records Limited | Information & communication | 2000 |
| Molake Properties Ltd | Real estate | 2019 |
| Momentum Enterprise Solutions Ltd | Information & communication | 2017 |
| Moonlight Investment Properties Ltd | Real estate | 2019 |
| Mopex Consulting Ltd | Professional & scientific | 2025 |
| Morbec Sports Limited | Wholesale & retail | 1995 |
| Mortgage Solutions Commercial Ltd | Financial services | 2024 |
| Mountcharm (S.E.) Limited | Real estate | 2000 |
| Mountcharm Group Limited | Real estate | 2008 |
| Mountcharm Limited | Other services | 1994 |
| Mountcrest Associates Ltd | Real estate | 2011 |
| Mountcrest Group Limited | Households | 2020 |
| Mountcrest Inc Ltd | Extraterritorial | 2011 |
| Mountjoygoldfinch Limited | Professional & scientific | 2015 |
| Mountjoygoldfinch Properties Ltd | Real estate | 2021 |
| Mountjoygoldfinch Therapy Limited | Health & social care | 2025 |
| Moxyna Limited | Real estate | 2020 |
| Mp&E Services Limited | Manufacturing | 2015 |
| MRP Accountancy Services Limited | Professional & scientific | 2004 |
| MRS Bounce Limited | Arts & recreation | 2022 |
| MS INV Ltd | Real estate | 2023 |
| Msmrubia Ltd | Health & social care | 2021 |
| Msri Consultants Ltd | Administrative & support | 2023 |
| Muchu Ltd | Wholesale & retail | 2021 |