| M & M Developments (Midlands) Limited | Construction | 2022 |
| M & M Spa Limited | Other services | 2009 |
| M and a Contracting Limited | Transport & logistics | 2014 |
| M D Trading U K Limited | Wholesale & retail | 2002 |
| M H & Sons (Midlands) Limited | Transport & logistics | 2022 |
| M J Interiors (Midlands) Limited | Construction | 2013 |
| M K Brickwork Limited | Construction | 2016 |
| M Kasliwal Limited | Health & social care | 2015 |
| M Mitchell Catering Limited | Hospitality | 2016 |
| M P Highclass Limited | Other services | 2000 |
| M Smith Quality Consulting Limited | Professional & scientific | 2025 |
| M&D Food and Wine Ltd | Wholesale & retail | 2020 |
| M. B. Distribution (Holdings) Limited | Financial services | 2020 |
| M. B. Distribution Investments Limited | Financial services | 2020 |
| M. Billingham & Co. Limited | Manufacturing | 1983 |
| M. Billingham Holdings Limited | Manufacturing | 2019 |
| M. Gray Fabrications Limited | Manufacturing | 2004 |
| M.B. Wheels & Tyres Limited | Wholesale & retail | 2023 |
| M.D. Green Renovation Limited | Construction | 2011 |
| M.K. Beauty Limited | Other services | 2015 |
| MAB Sales and Marketing Limited | Wholesale & retail | 2015 |
| MAC Gyver Limited | Manufacturing | 2018 |
| MAC Metal Trading Limited | Wholesale & retail | 2021 |
| Mace Martial Arts Ltd | Arts & recreation | 2023 |
| Macron AMB Ltd | Wholesale & retail | 2026 |
| MAF Consult Ltd | Professional & scientific | 2020 |
| Magnasnap Ltd | Professional & scientific | 2026 |
| Maha's Hair and Beauty Ltd | Other services | 2026 |
| Main MAN Supplies Limited | Wholesale & retail | 1989 |
| Mainair Compressors Ltd | Manufacturing | 2019 |
| Maldan Limited | Administrative & support | 2003 |
| Malkie Ltd | Wholesale & retail | 2024 |
| MAM Haulage Limited | Transport & logistics | 2012 |
| Mantech (Safety Systems) Limited | Professional & scientific | 2012 |
| Marbec Installations Ltd | Construction | 2026 |
| Mariospizzaandburger Ltd | Hospitality | 2025 |
| Markaman Logistics Limited | Transport & logistics | 2017 |
| Marlborough Print Limited | Administrative & support | 2019 |
| Marlie Automotive Supplies Ltd | Wholesale & retail | 2021 |
| Marlotte Limited | Health & social care | 2012 |
| Martik Ltd | Wholesale & retail | 2020 |
| Martin Castle Ltd | Construction | 2008 |
| MAS Specialist Fabricators Ltd | Manufacturing | 2022 |
| Masters Outdoor Leisure Limited | Arts & recreation | 2014 |
| Mastersskirtingboards Ltd | Manufacturing | 2025 |
| Matt the Bakers Limited | Wholesale & retail | 2018 |
| MBT Consulting Limited | Professional & scientific | 2022 |
| MC Metalworks Limited | Manufacturing | 2019 |
| Mcrx Ltd | Health & social care | 2025 |
| Mdtuk Holdings Limited | Administrative & support | 2021 |
| Mdtuk Property Limited | Administrative & support | 2021 |
| Mechatherm Engineering Limited | Manufacturing | 1973 |
| Mechatherm International Limited | Manufacturing | 1973 |
| Medi Pizza Ltd | Hospitality | 2026 |
| Mehr Building & Fencing Co Limited | Manufacturing | 2025 |
| Meighs & Westleys Limited | Manufacturing | 2008 |
| Meighs Limited | Manufacturing | 2004 |
| Memo's Pizza and Burgers Ltd | Hospitality | 2025 |
| Merchoid Limited | Wholesale & retail | 2015 |
| MGB and Sons Service Limited | Transport & logistics | 2019 |
| Mian Chuk Trade Ltd | Wholesale & retail | 2026 |
| Mick Coop Motors Limited | Wholesale & retail | 2015 |
| Middlemore Properties Ltd | Real estate | 2023 |
| Midland Cars Online Limited | Wholesale & retail | 2011 |
| Midland Coil Ltd | Manufacturing | 2024 |
| Midland Football League Limited | Arts & recreation | 2015 |
| Midland Joinery Services Limited | Manufacturing | 2000 |
| Midland Tube & Fabrications Ltd | Manufacturing | 2016 |
| Midlands Grounds Maintenance Limited | Administrative & support | 2026 |
| Milk Street House Limited | Hospitality | 2019 |
| Mills Forgings Limited | Manufacturing | 1946 |
| Mint Digital Print Limited | Extraterritorial | 2011 |
| MJ Properties Limited | Real estate | 2011 |
| MJA Transport Limited | Transport & logistics | 2018 |
| MJS Cars and Transport Ltd | Transport & logistics | 2019 |
| MK Highway Ltd | Transport & logistics | 2024 |
| MLC Site Services Ltd | Construction | 2016 |
| MMC Tax Accountancy Ltd | Professional & scientific | 2025 |
| MMN Enterprise Ltd | Health & social care | 2022 |
| Mokareem Limited | Construction | 2025 |
| Mokoteli Ltd | Health & social care | 2013 |
| Molly's Manes Limited | Other services | 2022 |
| Momentum Electronics Limited | Manufacturing | 1987 |
| Momentum Limited | Manufacturing | 1980 |
| Montheill Limited | Hospitality | 2020 |
| Montrose Carpentry & Joinery Ltd | Construction | 2023 |
| Moore Street Investments Limited | Real estate | 2021 |
| Moore Street Recycling Limited | Water & waste | 2020 |
| Morexon Limited | Financial services | 2025 |
| Morgan Riley Limited | Real estate | 2005 |
| Motherland Music Community Interest Company | Education | 2019 |
| Motion Logistic Services Ltd | Transport & logistics | 2025 |
| Motor Market Ltd | Wholesale & retail | 2005 |
| Motorselite Ltd | Wholesale & retail | 2025 |
| Mountain ARC Properties Ltd | Real estate | 2025 |
| MR Midi Skip Limited | Water & waste | 2010 |
| Mroke Properties Limited | Real estate | 2020 |
| Mroke Victoria Limited | Health & social care | 2013 |
| MS (Midlands) Ltd | Manufacturing | 2002 |
| Msanka Ltd | Financial services | 2023 |