| Lypiatt Landscapes Ltd | Administrative & support | 2016 |
| M & C Care Limited | Health & social care | 2006 |
| M a C P Investments Limited | Real estate | 2014 |
| M Jones Architect Ltd | Professional & scientific | 2014 |
| M&B Stores (Minchinhampton) Ltd | Wholesale & retail | 2025 |
| M&K Stroud Building Services Limited | Construction | 2018 |
| M.C. Construction Limited | Construction | 2003 |
| M.W. Ingredients Limited | Other services | 1997 |
| MA2 Medical Ltd | Health & social care | 2012 |
| Maasai Kitchen Limited | Hospitality | 2023 |
| Mablethorpe Wind Park Limited | Energy | 2000 |
| MAC Law Ltd | Professional & scientific | 2023 |
| Macbeth Lankester Ltd | Professional & scientific | 2015 |
| Machux Consulting Limited | Professional & scientific | 2014 |
| Mackson Transport Solutions Ltd | Transport & logistics | 2025 |
| Macorro Projects Limited | Information & communication | 1995 |
| Macseyco Limited | Hospitality | 2002 |
| MAD March Hare CAD Services Limited | Information & communication | 2010 |
| Madbees Ltd | Wholesale & retail | 2025 |
| Made Curious Limited | Information & communication | 2025 |
| Made in Stroud Limited | Hospitality | 1999 |
| Maestro Marketing Solutions Limited | Professional & scientific | 2023 |
| Magic Wand Film Services Limited | Other services | 2010 |
| Magnaghi UK (Holdings) Limited | Professional & scientific | 2021 |
| Magnaghi UK Limited | Manufacturing | 1998 |
| Magnificent Roots Ltd | Professional & scientific | 2026 |
| MAID2MEASURE Ltd | Other services | 2011 |
| Maintix Support Services Ltd | Administrative & support | 2026 |
| Maiwald & Mosse Ltd | Manufacturing | 2022 |
| Major Media Sales Limited | Professional & scientific | 2009 |
| Make Believe UN Limited | Arts & recreation | 2017 |
| Make IT Right Ltd | Arts & recreation | 2025 |
| Malchomes Ltd | Real estate | 2018 |
| Mana Minerals Ltd | Wholesale & retail | 2022 |
| Mango Business Services Ltd | Professional & scientific | 2017 |
| Manor Glazing Stroud Limited | Construction | 2020 |
| MAP16 Asset Management Ltd | Information & communication | 2017 |
| MAP16 RSB Tech Ltd | Information & communication | 2018 |
| Maplevine Limited | Professional & scientific | 2012 |
| Marah Trust | Health & social care | 2006 |
| Marcus Walters Limited | Administrative & support | 2008 |
| Margaret Reid Display Solutions Limited | Manufacturing | 2016 |
| Maria DA Silva LLP | | 2020 |
| Marine Communications Limited | Information & communication | 1996 |
| Marine Experts Limited | Professional & scientific | 2016 |
| Mark Davis Ltd. | Professional & scientific | 2002 |
| Mark Ferrar Studio Limited | Professional & scientific | 2022 |
| Mark Sheehan Building Consultancy Limited | Professional & scientific | 2006 |
| Marketing Mill Studios Ltd | Professional & scientific | 2025 |
| Marsh Mcneil Mentoring Ltd | Education | 2025 |
| Marshall's Plumbing Ltd | Construction | 2020 |
| Marston Smile Ltd | Extraterritorial | 2020 |
| Martec Associates Limited | Financial services | 1987 |
| Martin Jennings Limited | Arts & recreation | 2003 |
| Martyn Young Fire Proofing Consultancy Ltd | Public administration | 2019 |
| Masss Limited | Mining & quarrying | 2015 |
| MAT Collishaw Ltd | Arts & recreation | 2007 |
| MAT Symons Ltd | Professional & scientific | 2024 |
| Match CUT Music Ltd | Information & communication | 2026 |
| Matcha Life Ltd | Wholesale & retail | 2020 |
| Matchplay Club Ltd | Arts & recreation | 2014 |
| Matizmo Limited | Information & communication | 2006 |
| MAX Barr Antique Restoration Ltd | Manufacturing | 2010 |
| MAX Comfort Limited | Administrative & support | 2002 |
| Mayfly Sound Ltd | Arts & recreation | 2015 |
| Maynard Ltd | Professional & scientific | 1998 |
| Maynard Machinery Limited | Extraterritorial | 2010 |
| Maynard Motorsport Limited | Extraterritorial | 2010 |
| Maynard Properties Limited | Real estate | 2015 |
| Mays Electrical Ltd | Construction | 2018 |
| Mazandi Design Limited | Extraterritorial | 2026 |
| Mbld UK Ltd | Professional & scientific | 2018 |
| MBP Consulting Ltd | Information & communication | 2014 |
| Mcdbt Ltd | Professional & scientific | 2021 |
| Mcfrauline Ltd | Professional & scientific | 2026 |
| Mcgill Estates Ltd | Real estate | 2015 |
| Mcmath Media Services Ltd | Administrative & support | 2007 |
| MD Electrical Contracting Ltd | Construction | 2019 |
| MD Electrical Engineering Ltd | Construction | 2026 |
| Mdny Limited | Financial services | 2021 |
| MDP Safety Limited | Professional & scientific | 2019 |
| Meaco Woodwork Limited | Manufacturing | 2005 |
| Mechanical Electrical Clerk of Works Ltd | Construction | 2023 |
| Media & Entertainment Law Limited | Professional & scientific | 2018 |
| Medics-Acu Limited | Public administration | 2013 |
| Medieval Hall Management Company Limited | Households | 2008 |
| Medtech Compliance Solutions Limited | Professional & scientific | 2026 |
| Meglamedia Ltd | Households | 2026 |
| Meko Electrical Services Limited | Construction | 2009 |
| Meningitis NOW | Health & social care | 1990 |
| Meningitis Trust | Health & social care | 2013 |
| Meningitis Trust Trading Limited | Administrative & support | 1990 |
| Mercer Masonry & Conservation Ltd | Construction | 2026 |
| Mercer Media Ltd | Information & communication | 2017 |
| Merchant Wind Park (East Kilbride) Limited | Energy | 1999 |
| Mercury EDU Limited | Education | 2004 |
| Mercury Glazing Services Limited | Administrative & support | 2008 |
| Mercury Glazing Supplies Ltd | Manufacturing | 2002 |
| Mercury Group Holdings Limited | Manufacturing | 2003 |
| Merlin IT Consultancy Ltd | Information & communication | 2010 |