| Mill Street (Stone) Management Limited | Households | 2004 |
| Millar Sandy Limited | Real estate | 2003 |
| Miller and Turner Engineering Limited | Manufacturing | 2025 |
| Miller Engineering Limited | Professional & scientific | 2022 |
| Millfield Medical Limited | Extraterritorial | 2010 |
| Millingtons Builders Limited | Construction | 2025 |
| Million-Power Engineering Machinery Co., Ltd. | Extraterritorial | 2017 |
| Millmoore Building Services Ltd | Construction | 2007 |
| Milner Autotech Ltd | Wholesale & retail | 2012 |
| Mind Made Marketing Limited | Professional & scientific | 2017 |
| Mindersconsult Ltd | Information & communication | 2022 |
| Miners Arms (Swadlincote) Limited | Hospitality | 2024 |
| Minerva Accounting & Bookkeeping Services Ltd | Professional & scientific | 2026 |
| Minewin Trading Ltd | Wholesale & retail | 2026 |
| Ming Yang Trading Co., Ltd | Extraterritorial | 2015 |
| Mingchem Limited | Extraterritorial | 2011 |
| Mini Shirts UK Limited | Wholesale & retail | 2025 |
| Miniature Shetland Therapy Ponies Ltd | Administrative & support | 2019 |
| Mint Fintech Limited | Information & communication | 2022 |
| Mint Grounds Maintenance Limited | Administrative & support | 2026 |
| Miracle QG Ltd | Wholesale & retail | 2025 |
| Mirror Mirror Medical Aesthetics Ltd. | Health & social care | 2012 |
| Miska Limited | Hospitality | 2004 |
| Missy ELZ Ltd | Other services | 2021 |
| Miston Power Consultants Ltd | Professional & scientific | 2019 |
| Miteri Property Ltd | Real estate | 2021 |
| Mithandele Driver Training Ltd | Education | 2025 |
| Mitsun Ltd | Energy | 2023 |
| Miusse Limited | Wholesale & retail | 2023 |
| MJ Bistros Limited | Hospitality | 2025 |
| MJ Metal Magic Limited | Manufacturing | 2020 |
| MJ Retail Solutions Limited | Wholesale & retail | 2013 |
| Mjcgl Trading Co., Limited | Wholesale & retail | 2025 |
| MJP Electrical and Mechanical Services Limited | Manufacturing | 2005 |
| MJR Properties and Sons Ltd | Households | 2025 |
| Mjsmzuwnz Ltd | Wholesale & retail | 2026 |
| MJW Property Limited | Construction | 2021 |
| MK Cafe Stafford Ltd | Hospitality | 2025 |
| MKD Properties (London) Ltd | Households | 2025 |
| Mkhs Ventures Ltd | Real estate | 2025 |
| ML (White Hart) Ltd | Hospitality | 2021 |
| MLD Rail Consultant Ltd | Professional & scientific | 2016 |
| MLR Transport Ltd | Administrative & support | 2019 |
| MLT (Staffordshire) Ltd | Hospitality | 2022 |
| MMJ Leisure Limited | Hospitality | 2018 |
| MMM Medics Limited | Professional & scientific | 2021 |
| MMV Labs Limited | Manufacturing | 2014 |
| MN Property Investments Staffordshire Limited | Real estate | 2019 |
| Mnra Ltd | Real estate | 2025 |
| Mo's Barbers 41 Ltd | Other services | 2025 |
| Mobile Leisure Vehicle Services Ltd | Wholesale & retail | 2010 |
| Moddelo Properties Limited | Financial services | 2025 |
| Modena Import and Export Co., Ltd. | Manufacturing | 2024 |
| Modern Pro Ltd | Wholesale & retail | 2024 |
| Modivnine Ltd | Manufacturing | 2025 |
| Moffat Barbers Limited | Other services | 2024 |
| Mogel Industry Co., Ltd | Wholesale & retail | 2024 |
| Molo CSG Ltd | Financial services | 2023 |
| Momentum Digital Retail Solutions Ltd | Wholesale & retail | 2025 |
| Monica LUZ Boutique & Lifestyle Ltd | Wholesale & retail | 2022 |
| Monitech Limited | Manufacturing | 2012 |
| Monk & Smuggler Ltd | Hospitality | 2023 |
| Monken Ltd | Wholesale & retail | 2022 |
| Monthly Alzheimer's Support Evening Limited | Health & social care | 2010 |
| Montjack Investment Group Ltd | Financial services | 2019 |
| Montjack Limited | Construction | 2019 |
| Mooiklippe Limited | Information & communication | 2021 |
| Moon and Star I Consultant Services Ltd | Financial services | 2019 |
| Moonieco Ltd | Manufacturing | 2024 |
| Moorcroft Rentals Ltd | Real estate | 2021 |
| Moorcroft Services Ltd | Construction | 2018 |
| Moore Building Limited | Construction | 2015 |
| Moore Roofing Solutions Ltd | Construction | 2019 |
| Moot Technologies Limited | Wholesale & retail | 2023 |
| Moot Trading Ltd | Wholesale & retail | 2016 |
| Moreton Developments Limited | Construction | 1998 |
| Morgan Elizabeth Hairdressing Ltd | Other services | 2018 |
| Morgan Rushworth Limited | Extraterritorial | 2012 |
| Morgani Birchall Limited | Health & social care | 2024 |
| MOS Lighting (UK) Ltd | Wholesale & retail | 2007 |
| Mosaic Executive Search Limited | Administrative & support | 2016 |
| Mosaic Recruitment Holdings Limited | Financial services | 2021 |
| Mosell Corp Ltd | Wholesale & retail | 2022 |
| Moslia Import Export Co., Ltd | Wholesale & retail | 2015 |
| Motex Spares Ltd | Wholesale & retail | 2017 |
| Motivapor Limited | Wholesale & retail | 2017 |
| Motivation, Joy & Wellness Coaching Services Ltd | Health & social care | 2024 |
| Moto Transporter Limited | Transport & logistics | 2016 |
| Motorcentre Limited | Wholesale & retail | 2003 |
| Motorsports Photography Limited | Information & communication | 2011 |
| Motouk Ltd | Wholesale & retail | 2019 |
| Mottaghan Reid Limited | Construction | 2023 |
| Mousa Trading Limited | Wholesale & retail | 2025 |
| Move That Car Deliveries Limited | Transport & logistics | 2014 |
| Movement & Milestones Ltd | Education | 2026 |
| Mowgli Adventures Media Ltd | Information & communication | 2021 |
| MPC Installations Ltd | Construction | 2018 |
| MPG (Tpow) Ltd | Hospitality | 2022 |
| MPI Lettings Ltd | Real estate | 2024 |
| Mpower Consultancy Limited | Professional & scientific | 2024 |