| MA Fave Ltd | Manufacturing | 2023 |
| MA Muzic Productions Limited | Arts & recreation | 2024 |
| MAA Project Services Ltd | Other services | 2012 |
| MAB Carpentry Limited | Manufacturing | 2026 |
| Mabestudio Ltd | Information & communication | 2021 |
| MAC Property Lettings (Midlands) Ltd | Real estate | 2003 |
| MAC Steels Limited | Construction | 2002 |
| MAC Tech Group Ltd | Information & communication | 2017 |
| Machenry Enterprises Limited | Real estate | 2026 |
| Machinor Limited | Professional & scientific | 2006 |
| Mackenzie-Smith Plant Limited | Construction | 2021 |
| Mackwell Components Limited | Manufacturing | 2025 |
| Mackwell Emergency Limited | Manufacturing | 2025 |
| Mackwell Lighting Limited | Manufacturing | 2025 |
| MAD Health Ltd | Health & social care | 2010 |
| Madcha Residentials Limited | Real estate | 2025 |
| Maddock Cottages Ltd | Real estate | 2024 |
| Made 2 Measure Mattress Ltd | Wholesale & retail | 2005 |
| Made IT Moments Ltd | Transport & logistics | 2023 |
| Made Simple Technology Limited | Administrative & support | 2009 |
| Madeleine Berry Limited | Professional & scientific | 2026 |
| Madewell Holdings Limited | Real estate | 1998 |
| Madewell Products Limited | Manufacturing | 1987 |
| Magakris Ltd | Transport & logistics | 2015 |
| Magique Lashes Limited | Wholesale & retail | 2024 |
| Magpie Apothecary Ltd | Wholesale & retail | 2024 |
| Maguire Europe Sales Limited | Wholesale & retail | 2008 |
| Maibelle Mortgage Solutions Ltd | Professional & scientific | 2022 |
| Maids 2 YOU Ltd | Wholesale & retail | 2023 |
| Make a Different Noise Ltd | Administrative & support | 2016 |
| Make Energy Ltd | Professional & scientific | 2022 |
| Make New Friends Ltd | Other services | 2018 |
| Make Television Limited | Information & communication | 2012 |
| Mala Estates Limited | Real estate | 2018 |
| Mala Group Holdings Ltd | Real estate | 2023 |
| Mala Homes Developments Limited | Construction | 2022 |
| Mala Homes Ltd | Real estate | 2016 |
| Mala Leather Ltd | Wholesale & retail | 2007 |
| Mala Rose and Crown Ltd | Real estate | 2023 |
| Malonesbespokeinteriors Ltd | Manufacturing | 2022 |
| Malted Waffle Company (Equipment) Limited | Manufacturing | 2017 |
| Malted Waffle Company (Frozen) Limited | Manufacturing | 2017 |
| Malted Waffle Company (IP) Limited | Professional & scientific | 2018 |
| Malted Waffle Company Limited | Manufacturing | 2002 |
| Mamod (2025) Ltd | Manufacturing | 2025 |
| Mamod Spares Limited | Manufacturing | 2024 |
| Manapil Limited | Information & communication | 2024 |
| Mandrive Ltd | Transport & logistics | 2019 |
| Mane Salon Ltd | Other services | 2025 |
| Mani & Shiny Foods Ltd | Hospitality | 2025 |
| Mani Service Ltd | Wholesale & retail | 2026 |
| Manley Construction Ltd | Construction | 2026 |
| Manning Wardle Locomotives Limited | Extraterritorial | 2004 |
| Mannuu Ltd | Transport & logistics | 2025 |
| Manor Farm Fruits Ltd | Agriculture & fishing | 2011 |
| Manor Vehicles Limited | Wholesale & retail | 2018 |
| Mansard Carpentry Ltd | Construction | 2011 |
| Mansard Developments Limited | Construction | 2019 |
| Mansard Estates Limited | Real estate | 2016 |
| Mansell's Agricultural & Groundworks Development Ltd | Administrative & support | 2023 |
| Mansell's Aquatics & Garden Design Ltd | Administrative & support | 2023 |
| Mansion Decor Limited | Construction | 2018 |
| Manstal Group Holdings Limited | Financial services | 2026 |
| Manstal Holdings Limited | Construction | 2015 |
| Manstal Limited | Construction | 1983 |
| Manstal Mechanical & Building Services Ltd | Construction | 2007 |
| Mantell Properties Limited | Real estate | 2015 |
| Manu Agrawal Medical Services Ltd | Health & social care | 2007 |
| Manufacturing Technical & Engineering Specialists (UK) Limited | Wholesale & retail | 2011 |
| Maple Vale Securities Limited | Administrative & support | 2006 |
| Mapletime Limited | Real estate | 2013 |
| Maraboustork Limited | Information & communication | 2007 |
| Marandsys Limited | Professional & scientific | 2005 |
| Marbridge Productions Tamworth Limited | Professional & scientific | 2011 |
| Marc Evans Carpentry Limited | Construction | 2006 |
| Marc Joesbury Limited | Professional & scientific | 2022 |
| Marcas Group Limited | Real estate | 1999 |
| Marco Benito Limited | Other services | 2019 |
| Mariahemin Ltd | Wholesale & retail | 2026 |
| Marieland Makeup & Beauty Ltd | Wholesale & retail | 2024 |
| Marin Rusu Transport Limited | Transport & logistics | 2015 |
| Marina View Fazeley Ltd | Administrative & support | 2015 |
| Mariner (Lichfield Road) Management Company Limited | Real estate | 2007 |
| Mariner GM Cafe Limited | Hospitality | 2023 |
| Maritime Service Line UK Limited | Transport & logistics | 2009 |
| Mariusz JUR Ltd | Transport & logistics | 2018 |
| Mark Brookes IFA Limited | Administrative & support | 2005 |
| Mark Lambert Consulting Ltd | Professional & scientific | 2023 |
| MARK118 Logistics Ltd | Transport & logistics | 2017 |
| Market Street Mortgages & Protection Limited | Financial services | 2024 |
| Marks Insurance Consultants Limited | Financial services | 2009 |
| Marleen Lettings Limited | Real estate | 2025 |
| Maroon Management Ltd | Professional & scientific | 2021 |
| Martick Construction Limited | Administrative & support | 2014 |
| Martick Properties Ltd | Real estate | 2023 |
| Martigon Ltd | Professional & scientific | 2025 |
| Martin Plowman Promotions Limited | Arts & recreation | 2007 |
| Martin Wright Recruitment Ltd | Administrative & support | 2023 |
| Marven Newbold Limited | Households | 2019 |
| Mary Zhang Limited | Health & social care | 2016 |