| Mcglaun Ltd | Transport & logistics | 2016 |
| Mcguigan Estates Group Limited | Real estate | 2026 |
| Mckenzie Law Limited | Professional & scientific | 2003 |
| Mclaren Online Limited | Information & communication | 2024 |
| Mcloughlin Psychology Ltd | Education | 2025 |
| Mcsweeney Architecture Ltd | Professional & scientific | 2020 |
| MD Meehan Ltd | Professional & scientific | 2026 |
| MD Partnerships Limited | Financial services | 2022 |
| MDA Events Ltd | Professional & scientific | 2022 |
| MDA Mitchell Management Limited | Other services | 2012 |
| MDA Properties Ltd | Real estate | 2017 |
| MDH Events Limited | Hospitality | 2023 |
| MDK Facilities Services Limited | Professional & scientific | 2016 |
| Mdlon (2021) Ltd | Real estate | 2021 |
| MDP Contracting Ltd | Information & communication | 2019 |
| MDS Petrochemical Supplies Limited | Manufacturing | 2007 |
| MDV Courier Limited | Transport & logistics | 2025 |
| Meadow View Barns Management Company Limited | Households | 2024 |
| Meds at Home Limited | Wholesale & retail | 2010 |
| MEE2 Retail Limited | Wholesale & retail | 2010 |
| Meerooz Ltd | Wholesale & retail | 2020 |
| Meet EAT Drink Ltd | Hospitality | 2025 |
| Megan Campbell 28 Limited | Arts & recreation | 2023 |
| Meinertube Ltd | Wholesale & retail | 2019 |
| Melhado Signature Properties Ltd | Real estate | 2025 |
| Menstylegroup a Ltd | Other services | 2018 |
| Mercury Training Services Ltd | Education | 2005 |
| Mercy Duffell Limited | Manufacturing | 2026 |
| Meredith & Castle Ltd | Real estate | 2025 |
| Meridian Capital Group Ltd | Real estate | 2024 |
| Merlin Powder Characterisation Limited | Professional & scientific | 2010 |
| Merry Hill Private Hire Limited | Transport & logistics | 1997 |
| Messenger Transport Limited | Transport & logistics | 2017 |
| MET Property UK Ltd | Real estate | 2018 |
| Metakal International Limited | Arts & recreation | 1990 |
| Metal IQ Ltd | Information & communication | 2025 |
| Metcat Ltd | Water & waste | 2012 |
| Mets Laboratories UK Ltd | Professional & scientific | 2023 |
| MF Property Investors Ltd | Real estate | 2020 |
| MG Outdoor Living Ltd | Manufacturing | 2026 |
| MG Training & Events Ltd | Health & social care | 2014 |
| MH Brothers Ltd | Hospitality | 2022 |
| MH1 Properties Limited | Real estate | 2022 |
| MI23 Properties Limited | Real estate | 2023 |
| Mibi Serv Ltd | Hospitality | 2026 |
| Midcare Housing Support Ltd | Hospitality | 2021 |
| Midcare Ltd | Hospitality | 2025 |
| Midcare Properties Ltd | Real estate | 2024 |
| Midcare Services Ltd | Health & social care | 2015 |
| Midland Bright Steels Limited | Wholesale & retail | 2000 |
| Midland Drainage Limited | Water & waste | 2005 |
| Midland Electrical Services Ltd | Administrative & support | 2021 |
| Midland Motorcars (Brierley Hill) Limited | Wholesale & retail | 2013 |
| Midland Motorcars Limited | Wholesale & retail | 2004 |
| Midland Plant/Lifting Inspections Limited | Manufacturing | 2023 |
| Midland Plumbing Installations Limited | Construction | 2005 |
| Midland Structural Fabrications Limited | Extraterritorial | 2014 |
| Midland Structures Limited | Manufacturing | 2010 |
| Midland Supercream (Brierley Hill) Limited | Manufacturing | 1961 |
| Midland Theatre Services Limited | Arts & recreation | 2010 |
| Midland Transmission Holdings Limited | Administrative & support | 1996 |
| Midland Workshop Supplies Limited | Wholesale & retail | 2000 |
| Midlands Classic Motors Limited | Wholesale & retail | 2023 |
| Midlands Heating Solutions Limited | Construction | 2013 |
| Midlands Holding Group Limited | Financial services | 2020 |
| Midlands Motor House Ltd | Wholesale & retail | 2019 |
| Midlands Sheds and Summerhouses Limited | Construction | 2015 |
| Midlands Training Group Ltd | Other services | 2016 |
| Midlands Travel Solutions Limited | Administrative & support | 2024 |
| Midnightcrunch Ltd | Wholesale & retail | 2019 |
| Midpoint Trade Center Ltd | Wholesale & retail | 2017 |
| Midwinder Ltd | Administrative & support | 2018 |
| MIF Filter Systems Limited | Manufacturing | 1979 |
| Migand Ltd | Construction | 2021 |
| Migranna Ltd | Health & social care | 2024 |
| Mike Collins Recruitment Services Ltd | Administrative & support | 2024 |
| Mikmo Limited | Health & social care | 2016 |
| Mini Mall Limited | Wholesale & retail | 2025 |
| Mint Technology East Limited | Information & communication | 2024 |
| Mint Technology Group Limited | Financial services | 2018 |
| Mint Telecommunication Limited | Information & communication | 2013 |
| Mister Locs Ltd | Wholesale & retail | 2025 |
| MIT Investments Limited | Real estate | 2024 |
| Mitalent Recruitment Group Limited | Administrative & support | 2020 |
| Mitch's Swim Scheme Limited | Education | 2026 |
| MJ Green Accountancy Services Limited | Professional & scientific | 2011 |
| MJB Heating Services Ltd | Construction | 2025 |
| MJP Recycling Limited | Water & waste | 2012 |
| Mjp.Sales Ltd | Wholesale & retail | 2025 |
| MJS Elite Couriers Ltd | Transport & logistics | 2020 |
| MK Legacy Limited | Real estate | 2021 |
| ML21 Properties Ltd | Real estate | 2024 |
| MM Living Limited | Manufacturing | 2024 |
| MMK Scrub Solutions Ltd | Health & social care | 2014 |
| Mobility Aids Guide Ltd | Manufacturing | 2009 |
| Mocha Deli Ltd | Hospitality | 2023 |
| Mohammedi Property Investments Limited | Real estate | 2002 |
| Molineux Investments Limited | Financial services | 2021 |
| Momma JS Limited | Hospitality | 2024 |
| Monster Nursery Ltd | Education | 2019 |