| MCN Guest Properties Limited | Construction | 2015 |
| Mcore Ventures Limited | Administrative & support | 2025 |
| MCS Aesthetic Academy Limited | Health & social care | 2021 |
| MCS Aesthetics Limited | Health & social care | 2020 |
| MCS Beauty Limited | Other services | 2022 |
| MCS Property Development Ltd | Real estate | 2023 |
| MDH Leisure Ltd | Professional & scientific | 2018 |
| Mdhh Limited | Hospitality | 2026 |
| MDW Mortgage Solutions Ltd | Financial services | 2025 |
| Meachem Holdings Ltd | Financial services | 2024 |
| Medical Locum Solution Limited | Health & social care | 2010 |
| Meds 4 Your Pets Ltd | Professional & scientific | 2023 |
| Melbourne Close Management Company Limited | Extraterritorial | 2010 |
| Melissa Jayne Limited | Manufacturing | 2012 |
| Meller and Co. Accountants Limited | Professional & scientific | 2004 |
| Meller Bromsgrove Limited | Professional & scientific | 2005 |
| Mepsolve Limited | Construction | 2025 |
| MER Design Limited | Professional & scientific | 2007 |
| Mercia Heating Ltd | Construction | 2022 |
| Merek Engineering Limited | Manufacturing | 1983 |
| Merlin Asphalt Mixers Limited | Manufacturing | 2015 |
| Metro Lifts Limited | Extraterritorial | 2026 |
| Mffh Limited | Professional & scientific | 2011 |
| MG Installs Ltd | Construction | 2021 |
| MGE Renault Specialist and Service Centre Ltd | Wholesale & retail | 2009 |
| MH Electrical (Midlands) Ltd | Construction | 2021 |
| MH Offshore Electrical Rope Access Ltd | Construction | 2022 |
| Mhcs Investments Limited | Professional & scientific | 2024 |
| Mibed Limited | Manufacturing | 2023 |
| MIC Check Entertainment Ltd | Administrative & support | 2024 |
| Mick Donalds Limited | Hospitality | 2017 |
| Micki Consiglio Ltd | Arts & recreation | 2024 |
| Micro Precision (Midlands) Ltd | Professional & scientific | 1990 |
| Midland Architectural Ltd | Professional & scientific | 2023 |
| Midland Bearings Limited | Wholesale & retail | 1993 |
| Midland Blinds Limited | Wholesale & retail | 2003 |
| Midland Medical Technology Ltd | Manufacturing | 2010 |
| Midland Stone Paving Limited | Other services | 2019 |
| Midland Super Cream Ltd | Manufacturing | 2025 |
| Midlands Chandlery Limited | Wholesale & retail | 2016 |
| Mids GD Ltd | Professional & scientific | 2015 |
| Midsteel Flanges and Fittings Limited | Wholesale & retail | 2006 |
| MIH Traders Ltd | Wholesale & retail | 2011 |
| Miles Better Grab Hire Ltd | Administrative & support | 2017 |
| Mill Barn Property Limited | Construction | 2017 |
| Millard Utilities Limited | Construction | 2024 |
| Millennial Services Limited | Information & communication | 2020 |
| Millers Brow NO. 2 Management Company Limited | Real estate | 2010 |
| Millett-Kirkham Heavy Haulage Ltd | Transport & logistics | 2025 |
| Minhas Realty Ltd | Construction | 2019 |
| Mint Lawn & Weed Ltd | Administrative & support | 2024 |
| Mitr Search Ltd | Administrative & support | 2023 |
| MJ Retreats Ltd | Real estate | 2025 |
| MJS Vehicle Solutions Ltd | Wholesale & retail | 2018 |
| MJW Expediting Limited | Professional & scientific | 2026 |
| MJW Structures Limited | Professional & scientific | 2007 |
| MK & SSB Properties Ltd | Real estate | 2025 |
| MK Bennett | Professional & scientific | 2025 |
| MK Resuscitation Training Limited | Professional & scientific | 2023 |
| MKS Contact Services Limited | Education | 2025 |
| MKW Contracting Ltd | Construction | 2026 |
| ML Subco Limited | Manufacturing | 1978 |
| ML Utilities Ltd | Construction | 2024 |
| MMG Flooring Ltd | Construction | 2024 |
| Mmpc Corporation Ltd | Professional & scientific | 2024 |
| MMR Financial Planning (Midlands) Limited | Financial services | 2000 |
| Mobi & ANU Ltd | Health & social care | 2024 |
| Molineux Properties Ltd | Real estate | 2024 |
| Moore and Jeavons Property Development Limited | Construction | 2026 |
| Moorecroft Holdings Limited | Financial services | 2026 |
| Moose That's WHY... Limited | Hospitality | 2022 |
| More Mascots Please CIC | Other services | 2013 |
| Morecpd Ltd | Education | 2020 |
| Moreton Reynolds Ltd | Information & communication | 2016 |
| Morgan Howles & Parry Estate Agents Ltd | Real estate | 2025 |
| Morris and Sons Properties Ltd | Real estate | 2021 |
| Moss Grove Dental Care Ltd | Health & social care | 2021 |
| Moss Grove Management Company Limited | Households | 2006 |
| Mount Pleasant Groundworks Ltd | Construction | 2026 |
| MPB Medical Ltd | Health & social care | 2024 |
| MPP (Kingswinford) Ltd | Administrative & support | 2024 |
| MR Utility Solutions Ltd | Professional & scientific | 2023 |
| MRA Electrical Contractors Ltd | Construction | 2023 |
| MRM CNC Machinery Ltd. | Manufacturing | 2019 |
| MRS Minch Cleaning Services Ltd | Administrative & support | 2022 |
| Mryn Holdings Ltd | Financial services | 2025 |
| MS Medicare Limited | Real estate | 2007 |
| MT LPG Engineering Limited | Professional & scientific | 2025 |
| MTI Welding Technologies Ltd | Manufacturing | 2005 |
| MTN Practice Ltd | Manufacturing | 2025 |
| Muay Thai Academy Dudley Limited | Arts & recreation | 2019 |
| Muckmasters Services Ltd | Transport & logistics | 2016 |
| Mucky Paws Grooming Studio Limited | Other services | 2003 |
| Mugged OFF Prints Ltd | Manufacturing | 2025 |
| Munslows Accountants Limited | Professional & scientific | 2013 |
| Murdoch Accountancy Services Limited | Professional & scientific | 2011 |
| Murrayfield Medical Writing Services Limited | Administrative & support | 2015 |
| Must EAT Food Limited Limited | Hospitality | 2025 |
| MW Advisory Consulting Ltd | Administrative & support | 2019 |
| MWT Consulting Limited | Professional & scientific | 2014 |