| Marches Global Limited | Manufacturing | 2011 |
| Marches Homes (Mill Lane) Ltd | Construction | 2021 |
| Marches Homes (Oak Cottage) Limited | Real estate | 2021 |
| Marches Homes Limited | Construction | 2020 |
| Marches Management Services Limited | Administrative & support | 2010 |
| Marches Owen Limited | Construction | 2024 |
| Marches Psychological Services Ltd | Health & social care | 2022 |
| Marches Transport Ltd | Transport & logistics | 2026 |
| Marden Primary Academy | Education | 2013 |
| Marden Shop Ltd | Wholesale & retail | 2019 |
| Marengo 90 Limited | Health & social care | 2022 |
| Margaret Allen House Management Company Limited | Households | 2011 |
| MARIFRED2MEDICAL Limited | Health & social care | 2026 |
| Marilyn’S Meadow Ltd | Other services | 2021 |
| Marinaged Wines Ltd | Wholesale & retail | 2023 |
| Marine Gardens Residents Association Limited | Households | 1978 |
| Marine Personnel Services Limited | Administrative & support | 2018 |
| Marine Services (Chirk) Limited | Manufacturing | 2006 |
| Maritime Guardian Limited | Professional & scientific | 2011 |
| Mark Bilney Ltd | Professional & scientific | 2023 |
| Mark Burton Property Maintenance Ltd | Administrative & support | 2025 |
| Mark Chester Limited | Information & communication | 2018 |
| Mark Freeman Limited | Construction | 2004 |
| Mark Rees Construction Limited | Construction | 2010 |
| Mark Western Consulting Limited | Information & communication | 2006 |
| Market Logic Limited | Professional & scientific | 2001 |
| Marko Holding Ltd | Wholesale & retail | 2015 |
| Marks Mobility Solutions Ltd | Professional & scientific | 2018 |
| Marlo Group Ltd | Wholesale & retail | 2023 |
| Maroon Construction Ltd | Construction | 2020 |
| Maroon Holdings Ltd | Real estate | 2022 |
| Marsden House Management Company Limited | Households | 2019 |
| Marsden House Residents Company Ltd | Households | 2023 |
| Marsh Street Thai Limited | Hospitality | 2026 |
| Marshall Evans Ltd | Construction | 2005 |
| Marshall Properties (Hereford) Limited | Real estate | 1996 |
| Marston Bros Limited | Construction | 1936 |
| Marstow Property Limited | Real estate | 2025 |
| Marta MAY Photography Limited | Professional & scientific | 2016 |
| Martha Trust Hereford Limited | Health & social care | 1996 |
| Martin Johnson Windows Limited | Extraterritorial | 2011 |
| Martin Meredith Plant Hire and Ground Works Limited | Administrative & support | 2013 |
| Martin Suff Electrical Services Limited | Construction | 2015 |
| Martin Watkins Limited | Construction | 2013 |
| Martyn Group Limited | Financial services | 2025 |
| Mary Kate Care Ltd | Health & social care | 2026 |
| Masala Booth Limited | Hospitality | 2023 |
| Mason Potatoes Limited | Wholesale & retail | 1998 |
| Mathieson and Bell Developments Limited | Real estate | 2018 |
| Mathieson and Bell Limited | Real estate | 2017 |
| Mathuran Ltd | Wholesale & retail | 2016 |
| Matt Hudd Martial Arts CIC | Education | 2017 |
| Matt Loader Ltd | Professional & scientific | 2020 |
| Matt Smalley Carpentry Limited | Extraterritorial | 2018 |
| Mattback Limited | Real estate | 2000 |
| Matthew Straker Ltd | Administrative & support | 2009 |
| Mattibba Ltd | Real estate | 2023 |
| Maurice and Crow Limited | Manufacturing | 2019 |
| MAX Cook Limited | Construction | 2025 |
| MAX Residential Group Ltd | Households | 2025 |
| Maxo FBD Limited | Health & social care | 2022 |
| Maxtan Ltd | Other services | 2023 |
| Maxwell Security Limited | Administrative & support | 2016 |
| MAY Walters Limited | Administrative & support | 2016 |
| Mayak Solutions Ltd | Professional & scientific | 2022 |
| Mayne Industries Limited | Information & communication | 2021 |
| Mayworks Ltd | Health & social care | 2026 |
| Mazurek Cafe Ltd | Wholesale & retail | 2025 |
| MB & SJ Properties Limited | Real estate | 2016 |
| MB Safety Solutions Limited | Professional & scientific | 2022 |
| MBJ Building & Development Ltd | Construction | 2018 |
| Mbuyu Capital Partners Limited | Professional & scientific | 2014 |
| MC Educae Limited | Education | 2023 |
| Mccand Holdings Ltd | Hospitality | 2023 |
| Mccormack Plumbing & Heating Ltd | Construction | 2022 |
| Mcct Ltd | Manufacturing | 2013 |
| Mcglone Property Ltd | Real estate | 2017 |
| MCH Cloud Limited | Information & communication | 2019 |
| Mchugo Hospitality Ltd | Hospitality | 2019 |
| Mckellars Ironwork Limited | Manufacturing | 2025 |
| Mckelvie Solutions Limited | Information & communication | 2008 |
| MCL Ventures Ltd | Real estate | 2014 |
| Mctip IT Limited | Information & communication | 2010 |
| MD Offshore Contracting Limited | Construction | 2025 |
| MDP Builders Limited | Construction | 2010 |
| MEA VIA Cibus Limited | Manufacturing | 2023 |
| Meanwhilebackattheoffice Limited | Information & communication | 2016 |
| Mebin Manjaly Ltd | Wholesale & retail | 2025 |
| Mechanical Box Ltd | Professional & scientific | 2012 |
| Meddox Limited | Real estate | 2019 |
| Medhurst Enterprises Ltd | Extraterritorial | 2015 |
| Medi-Khel Ltd | Wholesale & retail | 2022 |
| Mediasphere Group Ltd | Information & communication | 2016 |
| Medigraph Imaging Limited | Manufacturing | 1989 |
| Medlar Capital Limited | Financial services | 2020 |
| Medpract Limited | Health & social care | 2013 |
| Meet ME at the Top Limited | Administrative & support | 2013 |
| Melcon Electrical Limited | Real estate | 2008 |
| Melcon Hereford Limited | Construction | 1990 |
| Melhuish Property Ltd | Real estate | 2021 |