| Marlene Limited | Real estate | 2002 |
| Marmalady Property Limited | Real estate | 2021 |
| Marnie's Sarnie's LP | | 2010 |
| Marsh Property Group Investments Ltd | Real estate | 2024 |
| Marston Green Estates Limited | Real estate | 1935 |
| Martin Brent Limited | Professional & scientific | 2007 |
| Martline Limited | Professional & scientific | 1998 |
| Marvel Carpets Ltd | Wholesale & retail | 2022 |
| Mash Designs Limited | Administrative & support | 2006 |
| Mason Farms (Bromsgrove) Limited | Real estate | 2017 |
| Masterfinish Limited | Administrative & support | 2003 |
| Masters Creative Ltd | Wholesale & retail | 2021 |
| Masters Knowles Developments Ltd | Construction | 2018 |
| Mastfab Limited | Manufacturing | 2012 |
| Masuki Limited | Other services | 2024 |
| Matchless Trading Ltd | Wholesale & retail | 2025 |
| Matelin Holdings Limited | Real estate | 2019 |
| Matrix LE Ltd | Real estate | 2020 |
| MAX Security Group Limited | Administrative & support | 2023 |
| Maxkrista Ltd | Extraterritorial | 2012 |
| Maxwell Acting Limited | Arts & recreation | 2023 |
| Maybrook Developments (Appley Bridge) Ltd | Real estate | 2010 |
| Maybrook Investments (Parc Menai) Ltd | Professional & scientific | 2020 |
| Maybrook Investments Limited | Real estate | 2012 |
| Mayfield Mews (Catshill) Management Company Limited | Households | 2022 |
| MB24.7RECOVERYANDTRANSPORT Ltd | Transport & logistics | 2024 |
| MBH Healthcare Ltd | Administrative & support | 2016 |
| MBL Financial Services Limited | Information & communication | 1999 |
| MBM Engineering Limited | Administrative & support | 2003 |
| MBS Design & Build Limited | Construction | 2013 |
| MC Houghton Properties Ltd | Real estate | 2021 |
| Mcdermott Interior Projects Ltd | Construction | 2025 |
| Mcgrath Bros. Construction Limited | Construction | 1967 |
| Mchale Holdings Ltd. | Hospitality | 2017 |
| Mcubedb Limited | Information & communication | 2021 |
| MD Discounts Northfield Ltd | Wholesale & retail | 2026 |
| MDC Integrated Services Ltd | Information & communication | 2016 |
| MDE Healthcare Limited | Health & social care | 2018 |
| MDS Electrical (Bromsgrove) Limited | Construction | 2021 |
| Meadow Park Football Club Limited | Arts & recreation | 2016 |
| Meadow Studios Wellness Limited | Arts & recreation | 2024 |
| Meadow Vale Properties Ltd | Real estate | 2021 |
| Meadow Vale Publishing Ltd | Wholesale & retail | 2021 |
| Meadowbank Tree Services Ltd | Administrative & support | 2013 |
| Meadowfield Lawncare Ltd | Administrative & support | 2017 |
| Meadows Farm Vets Limited | Professional & scientific | 2010 |
| Mear Software Solutions Limited | Information & communication | 2015 |
| Mechanical Car Services Limited | Wholesale & retail | 2019 |
| Mechoair Limited | Energy | 2024 |
| Meda Medical Limited | Health & social care | 2024 |
| Medlinks ABO Limited | Health & social care | 2023 |
| Meeraj Shah Limited | Health & social care | 2015 |
| Meet & Street Ltd | Hospitality | 2023 |
| Mega Grab Ltd | Water & waste | 2021 |
| Melpark Properties Limited | Extraterritorial | 2002 |
| Mercia Industrial & Commercial Cleaning Ltd | Administrative & support | 2002 |
| Mercian Plumbing and Heating Services Ltd | Construction | 2022 |
| Mercian Surgical Supply Co. Limited | Manufacturing | 1968 |
| Merlesque Ltd | Agriculture & fishing | 2026 |
| Merlin Network Services Limited | Information & communication | 2002 |
| Mermaid Joinery Ltd | Manufacturing | 2011 |
| Merman Holdings Limited | Financial services | 2024 |
| Merman Limited | Administrative & support | 2005 |
| Meryll Properties Ltd | Real estate | 2021 |
| Mesh Corporate Ltd | Wholesale & retail | 2025 |
| Meta AI Limited | Information & communication | 2016 |
| Metal & Ores Limited | Real estate | 2006 |
| Metaverse Artificial Intelligence Ltd | Information & communication | 2022 |
| Meteor Works (UK) Limited | Manufacturing | 2014 |
| Metrorise Ltd | Wholesale & retail | 2024 |
| MFZ Trading Ltd | Wholesale & retail | 2025 |
| MG Prep & Paint Ltd | Construction | 2020 |
| MGM Property Developers Limited | Real estate | 2025 |
| MH Vehicle Movements Limited | Administrative & support | 2022 |
| Mhassan Traders Ltd | Wholesale & retail | 2025 |
| MI Solutions & Services Limited | Professional & scientific | 2012 |
| Michael Y K WEE Limited | Health & social care | 2010 |
| Michelle Claire Smith Ltd | Education | 2023 |
| Mick Davies Plant Ltd | Construction | 2017 |
| Middlemore Tree Surgery Ltd | Agriculture & fishing | 2023 |
| Middleton 20 Limited | Wholesale & retail | 2025 |
| Midland Associates Limited | Professional & scientific | 2009 |
| Midland Commercial Estates Limited | Construction | 1999 |
| Midland Food Bakery Limited | Administrative & support | 2012 |
| Midland Foods Bakery Solihull Limited | Wholesale & retail | 2015 |
| Midland Foods Limited | Wholesale & retail | 1994 |
| Midland Foods Trading Limited | Administrative & support | 2012 |
| Midland Industrial Temperature Solutions Company Limited | Administrative & support | 2004 |
| Midland Leisure Properties Limited | Real estate | 1995 |
| Midland Linen Services Limited | Manufacturing | 1985 |
| Midland Materials Handling Co. Limited | Manufacturing | 1981 |
| Midland Paper Products Limited | Manufacturing | 2003 |
| Midland Reproduction Mirrors Limited | Wholesale & retail | 2002 |
| Midland Vehicle Solutions Limited | Wholesale & retail | 2021 |
| Midlands Air Systems Limited | Manufacturing | 2024 |
| Midlands Fire Tech Ltd | Professional & scientific | 2024 |
| Midlands Industries Limited | Professional & scientific | 2026 |
| Midlands Premium Homecare Ltd | Health & social care | 2026 |
| Midpoint Roofing and Cladding Ltd | Construction | 2024 |
| Midtech Building Services Limited | Construction | 2017 |