| Manor Kitchens UK Limited | | 2005 |
| Manor Park Aesthetics Limited | Health & social care | 2020 |
| Manor Road (Penn) Management Company Limited | Households | 2026 |
| Mansell Mews Management Company Limited | Households | 2021 |
| Many Doodles Natural Treats Limited | Manufacturing | 2023 |
| Maple (247) Limited | Households | 2005 |
| Maple Medicals Limited | Health & social care | 2015 |
| MAR Motorsport Ltd | Wholesale & retail | 2011 |
| Marcia Edwards Dance C.I.C. | Arts & recreation | 2025 |
| Marcus C Consulting Limited | Information & communication | 2013 |
| Marh Trade Limited | Wholesale & retail | 2026 |
| Mark and Martins ALE Distributions Ltd | Hospitality | 2015 |
| Mark Harvey Properties Ltd | Real estate | 2018 |
| Market Locator Ltd | Professional & scientific | 2009 |
| Market Solutions Limited | Wholesale & retail | 2010 |
| Marketing International (FAR East) Ltd | | 1986 |
| Marketrite (Birmingham) Limited | Real estate | 2019 |
| Marketrite (Properties) Limited | Real estate | 1996 |
| Marley's Homeware Ltd | Wholesale & retail | 2024 |
| Marlow Estates (Midlands) Limited | Real estate | 2009 |
| Martin Hill Interiors Limited | Wholesale & retail | 1991 |
| Martin Ioan C Limited | Construction | 2026 |
| Mary Stevens Hospice(The) | Health & social care | 1985 |
| Masi Real Estate Limited | Real estate | 2008 |
| Maskat Limited | Professional & scientific | 2008 |
| Maskat Properties Ltd | Real estate | 2021 |
| Masons Court Limited | Professional & scientific | 2018 |
| Masq Films Ltd | Information & communication | 2023 |
| Mastitech Ltd | Construction | 2025 |
| Mateus Holdings Limited | Financial services | 2012 |
| Mathieson Consultants Ltd | Professional & scientific | 2016 |
| Matra Consulting Limited | Professional & scientific | 2025 |
| Matrix Global Limited | Construction | 2022 |
| Matt Billingham (Holdings) Ltd | Financial services | 2019 |
| Mattal Limited | Professional & scientific | 2011 |
| Mattdoesglasses Limited | Wholesale & retail | 2026 |
| Matthew Harris Ltd | Real estate | 2020 |
| Matthew James Kitchens (Birmingham) Limited | Manufacturing | 2025 |
| Matthew Parkin Bioeducational Limited | Information & communication | 2016 |
| Mawali Corporation Ltd | Administrative & support | 2017 |
| MAX Hart Ltd | Real estate | 2023 |
| Maxfaro Ltd | Professional & scientific | 2008 |
| Maxima Consultancy Services Ltd | Professional & scientific | 2025 |
| Maximum Gainz Limited | Wholesale & retail | 2022 |
| Maxpro Limited | Financial services | 2026 |
| Mayburys Mobile Mechanics Ltd | Wholesale & retail | 2022 |
| Mayrich Ltd | Manufacturing | 2022 |
| Mbhaul Ltd | Wholesale & retail | 2022 |
| MBT Traders Ltd | Wholesale & retail | 2025 |
| Mc-Construction Chemicals (UK) Mueller and Partners | | 2008 |
| Mcallister ROE Ltd | Wholesale & retail | 2026 |
| MCB Sweets & Party Supplies Ltd | Wholesale & retail | 2025 |
| Mccadden HR Ltd | Administrative & support | 2016 |
| Mcclure Hospitality Ltd | Hospitality | 2023 |
| Mcdermott & Co Developments 1 Limited | Real estate | 2026 |
| MCE Springform Limited | Manufacturing | 2015 |
| Mcfarling Consulting Ltd | Professional & scientific | 2018 |
| Mcgg Limited | Other services | 1998 |
| Mchomebrews Limited | Wholesale & retail | 2017 |
| Mcknight Heating Limited | Construction | 2022 |
| Mclean Legal Limited | Other services | 2021 |
| MDB Enterprises Ltd | Construction | 2016 |
| Mdsl Installations Limited | Construction | 2011 |
| ME Bolton and SON Ltd | Households | 2025 |
| Meadow Court Properties Limited | Real estate | 2003 |
| Meadow View (Hulland Ward) Management Company Limited | Households | 2024 |
| Meadowbrook Close (Bridgnorth) Management Company Limited | Households | 2026 |
| Meadowcroft Kennels Limited | Professional & scientific | 2016 |
| Mean Treats Ltd | Hospitality | 2025 |
| Meba Services Limited | Wholesale & retail | 2008 |
| Med-A-T Solutions Limited | Extraterritorial | 2005 |
| Medal Recruitment Ltd | Administrative & support | 2022 |
| Medasun Ltd | Professional & scientific | 2004 |
| Medexcel Limited | Professional & scientific | 2011 |
| Medi-Services Limited | Health & social care | 1992 |
| Media Manor Ltd | Professional & scientific | 2009 |
| Medicos-Rx LLP | | 2007 |
| Medics Run Club Ltd | Arts & recreation | 2026 |
| MEDS2YOU Ltd | Wholesale & retail | 2022 |
| MEI CHA LP | | 2026 |
| Meldrum and Smith Ltd | Manufacturing | 2020 |
| Meliorus Limited | Transport & logistics | 2022 |
| Mellors Carpentry & Construction Limited | Manufacturing | 2022 |
| Melton Union Ltd | Professional & scientific | 2010 |
| Memory Magnets Ltd | Wholesale & retail | 2025 |
| Mentoringme Ltd | Education | 2025 |
| Menumate Ltd | Administrative & support | 2025 |
| MER Group Limited | Construction | 2016 |
| Mercian Aviation Ltd | Transport & logistics | 2023 |
| Mercury Precision Limited | Manufacturing | 2002 |
| Merdab Limited | Financial services | 2018 |
| Meriden Financial Planning Limited | Professional & scientific | 2014 |
| Meriden Healthcare Limited | Wholesale & retail | 2022 |
| Meridian Digital HCM Ltd | Information & communication | 2026 |
| Merlin Management Limited | Professional & scientific | 2002 |
| Mermaid Marys Ltd | Wholesale & retail | 2024 |
| Merrimore House Limited | Health & social care | 2010 |
| Merrivale and Partners Limited | Professional & scientific | 2019 |
| Merrivale Holdings Limited | Professional & scientific | 2019 |
| Merrivale Property Limited | Construction | 2019 |