| M&M IT Trustees Limited | Extraterritorial | 2024 |
| M&M Road Transport Ltd | Transport & logistics | 2017 |
| M&M UK Properties Ltd | Real estate | 2020 |
| M&S Cleaning Service (Stoke) Ltd | Administrative & support | 2024 |
| M&S Property and Building Developments Limited | Construction | 2025 |
| M-Level Ltd | Manufacturing | 2023 |
| M-Viron (Staffs.) Limited | Information & communication | 2004 |
| M. T. Hand Limited | Construction | 2006 |
| M.A Services (Stoke) Limited | Professional & scientific | 2025 |
| M.A Support Consultancy Ltd | Information & communication | 2026 |
| M.A.C. Services & Solutions Limited | Financial services | 2013 |
| M.A.D Reptiles Limited | Agriculture & fishing | 2024 |
| M.E.M. Insurance Brokers Limited | Financial services | 1980 |
| M.H. Elcock and SON Limited | Transport & logistics | 1975 |
| M.I Property Developments Ltd | Construction | 2025 |
| M.J.Jones Services Ltd | Construction | 2005 |
| M.K. Coffe Ltd | Hospitality | 2025 |
| M.O Property Limited | Real estate | 2018 |
| M.Plumbing Limited | Construction | 2025 |
| M.R.B Home Developments Ltd | Real estate | 2023 |
| M.Sha Medica Ltd | Health & social care | 2022 |
| M.Sha Wellness and Aesthetics Clinic Limited | Health & social care | 2023 |
| M.W. Construction (DNL) Limited | Construction | 2006 |
| M3 Branding Limited | Professional & scientific | 2018 |
| M3INSTALLATIONS Ltd | Construction | 2025 |
| M6 Couriers and Light Haulage Limited | Transport & logistics | 2008 |
| M8 Automation Solutions Ltd | Information & communication | 2024 |
| M8 Cyber Security Solutions Ltd | Information & communication | 2024 |
| M8 Solutions Limited | Information & communication | 2020 |
| MA Legacy Group Limited | Real estate | 2026 |
| MA Links 3 Ltd | Wholesale & retail | 2023 |
| MA Restaurant (Stafford) Ltd | Wholesale & retail | 2019 |
| MA Training & Assessments Ltd | Education | 2024 |
| Ma-Ve International (UK) Ltd | Wholesale & retail | 2023 |
| Maak Holdings Ltd | Real estate | 2024 |
| Maak Payroll Services Ltd | Professional & scientific | 2024 |
| Maak Portfolio Ltd | Real estate | 2025 |
| Maanjoes Movers Co Ltd | Water & waste | 2024 |
| Maas Motors Ltd | Wholesale & retail | 2017 |
| Maaz Locums Limited | Health & social care | 2013 |
| Mabanda Limited | Health & social care | 2020 |
| Maburhill Property Limited | Real estate | 2021 |
| MAC Business Support Limited | Professional & scientific | 2011 |
| MAC Flames (Middleport) Ltd | Hospitality | 2020 |
| MAC Tool and Plant Hire Limited | Administrative & support | 2011 |
| MAC Tools South Cheshire Ltd | Wholesale & retail | 2026 |
| MAC Training & Consultancy Limited | Education | 2026 |
| Mac's Barbers Limited | Other services | 2021 |
| Macagna Ltd | Hospitality | 2010 |
| Macao Ltd | Transport & logistics | 2021 |
| Macboski Ltd | Construction | 2018 |
| Maccimedia Limited | Professional & scientific | 2019 |
| Macclesfield Flyfishers Club Limited | Arts & recreation | 2006 |
| Macelarie Traditionala Limited | Manufacturing | 2025 |
| MACH2 Healthcare Ltd | Professional & scientific | 2021 |
| Machin Plant Hire Ltd | Construction | 2017 |
| Mackeo Limited | Financial services | 2021 |
| Macmillan Group Ltd | Professional & scientific | 2026 |
| Macrigi Ltd | Wholesale & retail | 2015 |
| Macro Tech Tred Ltd | Information & communication | 2022 |
| MAD Business Process Outsourcing Ltd | Administrative & support | 2024 |
| MAD Hatters Hairdressing Limited | Other services | 2019 |
| MAD Store Ltd | Wholesale & retail | 2025 |
| Maddox Accountancy & Business Services Ltd | Professional & scientific | 2025 |
| Made's Healthy Flours (UK) Limited | Professional & scientific | 2014 |
| Madeair Hvac Systems Ltd | Construction | 2026 |
| Madeira Property Holdings Ltd | Real estate | 2026 |
| Madeley Park Estate Management Ltd | Households | 2021 |
| Madimah Limited | Wholesale & retail | 2021 |
| Madina Cultural Centre Ltd | Education | 2012 |
| Madrona Films Limited | Information & communication | 2018 |
| Mafio Healthcare Limited | Health & social care | 2022 |
| Maganda Medical Aesthetic Ltd | Health & social care | 2025 |
| Magcad Designs Ltd | Wholesale & retail | 2021 |
| Magesticgifts Ltd | Manufacturing | 2026 |
| Maggie-Tina Limited | Health & social care | 2013 |
| Maggio (South East) Limited | Real estate | 2026 |
| Magic Memories Group (UK) Ltd | Arts & recreation | 2009 |
| Magic Muffins Ltd | Manufacturing | 2025 |
| Magic Taxi Ltd | Transport & logistics | 2025 |
| Magical Haircut Sutton Ltd | Other services | 2020 |
| Magna Cura Limited | Health & social care | 2013 |
| Magna Projects Limited | Construction | 2021 |
| Magna Taverns Limited | Hospitality | 2022 |
| Magnetic Minds CIC | Education | 2025 |
| Magnific Tailoring Alteration Ltd | Other services | 2025 |
| Magnum Private Hire Ltd | Transport & logistics | 2020 |
| Magoo's Wines and Spirits Limited | Wholesale & retail | 2002 |
| Magrini (UK) Limited | Manufacturing | 1989 |
| Mahar Multi Service Limited | Wholesale & retail | 2025 |
| Mahbeer Privates Limited | Wholesale & retail | 2024 |
| Mahiki Racing Ltd | Wholesale & retail | 2023 |
| Mahreb Ltd | Wholesale & retail | 2025 |
| Mahwan Properties Ltd | Construction | 2021 |
| Maia Westwick Ltd | Extraterritorial | 2024 |
| Maid in Biddulph Ltd | Administrative & support | 2022 |
| Mailey Shop Ltd | Wholesale & retail | 2025 |
| Mailswift Limited | Information & communication | 2024 |
| Main Arena Fencing Ltd | Administrative & support | 2020 |
| Main Electrical Services Ltd | Administrative & support | 2016 |