| Mills Pyatt Audit Limited | Professional & scientific | 2021 |
| Mills Pyatt Holdings Limited | Financial services | 2021 |
| Mills Pyatt Limited | Professional & scientific | 1985 |
| Millstream Group Limited | Financial services | 1997 |
| Mimi Property Ltd | Real estate | 2022 |
| Mimir Solutions Limited | Information & communication | 2022 |
| Mimospd Ltd | Transport & logistics | 2025 |
| Mina Tandoori Ltd | Hospitality | 2019 |
| Mindful Meets Method Ltd | Wholesale & retail | 2026 |
| Mindsprout Education Ltd | Education | 2025 |
| Mingus PIC Limited | Real estate | 2021 |
| Minton Mews Management Company (Bromsgrove) Limited | Households | 1988 |
| Minu Natural Ltd | Wholesale & retail | 2026 |
| Mirage Property and Lets Limited | Real estate | 2023 |
| MIRATRANS15 Limited | Transport & logistics | 2021 |
| Mirror Mirror Hairdressing Redditch Ltd | Other services | 2015 |
| Mirzarp Homes Ltd | Real estate | 2025 |
| Mistair Limited | Manufacturing | 2011 |
| Misterabakes Ltd | Hospitality | 2020 |
| MJ Properties Investments Ltd | Real estate | 2025 |
| MJS Programs Ltd | Information & communication | 2025 |
| Mk.Du Investments Ltd | Real estate | 2024 |
| Mkds Property Ltd | Real estate | 2024 |
| MLK ISO Consultancy Ltd | Administrative & support | 2022 |
| MM Cleaning Limited | Households | 2003 |
| MM Commercial Services Limited | Administrative & support | 2007 |
| MM Stafford Limited | Administrative & support | 2022 |
| Mmaz Tech Ltd | Information & communication | 2026 |
| Mmfb Worcester Ltd | Real estate | 2022 |
| MMS Cleaning & Maintenance Ltd | Administrative & support | 2024 |
| MMS Facilities Management Limited | Other services | 2025 |
| MMS FM Ltd | Administrative & support | 2007 |
| Mobile Pet Supplies Limited | Wholesale & retail | 2013 |
| Mobility Bathing Group Limited | Administrative & support | 2005 |
| Mobility Group Limited | Professional & scientific | 2016 |
| Mobility Group Topco Limited | Financial services | 2016 |
| Moda Music Group Ltd | Information & communication | 2023 |
| Modaé Limited | Wholesale & retail | 2025 |
| Modern and Heritage Decor Ltd | Construction | 2024 |
| Modern Vision Limited | Construction | 2025 |
| Moje Wypieki Ltd | Administrative & support | 2016 |
| Molinna Limited | Extraterritorial | 1994 |
| Monarch Motor Company Limited | Wholesale & retail | 2011 |
| Monk's Fuels Limited | Wholesale & retail | 2022 |
| Monny Care Limited | Health & social care | 2013 |
| Monoply Ltd | Construction | 2024 |
| Monro Walker Limited | Extraterritorial | 1991 |
| Monsal Dale Limited | Construction | 2011 |
| Montrose Fasteners Limited | Other services | 1991 |
| Montuno Limited | Information & communication | 2024 |
| Monument Quality Ltd | Manufacturing | 2016 |
| Morce Limited | Professional & scientific | 2012 |
| Moreby Properties Limited | Real estate | 2014 |
| Moredale Electrical Distributors Limited | Wholesale & retail | 1987 |
| Moredale Limited | Wholesale & retail | 1986 |
| Morgan Bennett Holdings Limited | Professional & scientific | 1965 |
| Morgan's Motor Vehicles Ltd | Wholesale & retail | 2016 |
| Morreston Limited | Construction | 2000 |
| Morris (Redditch) Limited | Wholesale & retail | 1924 |
| Morris Brothers Electrical Limited | Construction | 2018 |
| Morris Roofing Services Ltd | Construction | 2023 |
| Mortek Limited | Wholesale & retail | 2004 |
| Mortimer Brickwork Ltd | Construction | 2023 |
| Mortimer Tree Services Ltd | Administrative & support | 2025 |
| Morton Meadow Holdings Ltd | Financial services | 2024 |
| Moss House Build Limited | Construction | 2025 |
| Most Technical Limited | Administrative & support | 2003 |
| Motor Assistance & Recovery Services Limited | Administrative & support | 2005 |
| Motorcycle Equipment Limited | Wholesale & retail | 2014 |
| Motorcycle Riders Hub Ltd | Information & communication | 2021 |
| Mount Mini Market Ltd | Wholesale & retail | 2025 |
| Mounthood Limited | | 1982 |
| Mova Electrics Ltd | Construction | 2024 |
| Move IT Midlands UK Ltd | Transport & logistics | 2007 |
| Move ME TOO Ltd | Real estate | 2021 |
| Moveying NOW Limited | Transport & logistics | 2026 |
| Moviro Investments Ltd | Construction | 2025 |
| Movonix Limited | Administrative & support | 2013 |
| Mpay Service Ltd | Wholesale & retail | 2018 |
| MPK Car & Commercial Limited | Wholesale & retail | 2013 |
| MPL Contracts Ltd | Construction | 2013 |
| Mqasim Limited | Manufacturing | 2025 |
| MR Pizza Redditch Ltd | Hospitality | 2020 |
| MR Prep Ltd | Hospitality | 2016 |
| MRS IT Limited | Information & communication | 2012 |
| MS Electrical Engineers & Contractors Limited | Construction | 2003 |
| MSB Freight Ltd | Transport & logistics | 2015 |
| MSH Homes Ltd | Real estate | 2025 |
| MSS Healthcare Limited | Health & social care | 2013 |
| MT Maintenance Contracts Ltd | Construction | 2014 |
| MTL Engineers Limited | Administrative & support | 2007 |
| Mudwalls Farm Limited | Wholesale & retail | 2020 |
| Mudwalls Food Group Limited | Extraterritorial | 2024 |
| Muhammad Mustafa Ltd | Real estate | 2025 |
| Mulberry Barn Ltd | Wholesale & retail | 2006 |
| Mulberry PM Services Limited | Professional & scientific | 2024 |
| Mulig Ltd | Information & communication | 2024 |
| Muller & Company (England) Limited | Extraterritorial | 1926 |
| Muller AES UK Limited | Manufacturing | 2025 |
| Muller Birmingham Limited | Extraterritorial | 2001 |