| MJM Shutters Ltd | Construction | 2025 |
| MJW Plant Services Ltd | Manufacturing | 2022 |
| MKE Trans Ltd | Transport & logistics | 2019 |
| MLP Automotive Ltd | Wholesale & retail | 2023 |
| MM Coolzone Ltd | Construction | 2025 |
| Mmarss Ltd | Public administration | 2025 |
| Mmondhe Limited | Wholesale & retail | 2025 |
| MMT Renewables Limited | Energy | 2025 |
| MN Portfolio Ltd | Health & social care | 2023 |
| MO Kitchen 10 Limited | Hospitality | 2016 |
| MO Propertyman Ltd | Real estate | 2025 |
| Mobile Phone Solutions Ltd | Wholesale & retail | 2002 |
| Model Health Performance Ltd | Arts & recreation | 2013 |
| Model Hobbies Ltd | Wholesale & retail | 2005 |
| Moderni Limited | Professional & scientific | 2024 |
| Moes Vapes Limited | Wholesale & retail | 2025 |
| Mohamad Kammouh DC Ltd | Health & social care | 2019 |
| Moll Telecom Service Ltd | Information & communication | 2023 |
| Mollimed Ltd | Health & social care | 2025 |
| Momv Group Ltd | Financial services | 2026 |
| Mondo Holdings Limited | Information & communication | 2023 |
| Moneyshake.Com Limited | Professional & scientific | 2007 |
| Monton Lounge Ltd | Hospitality | 2026 |
| Moonlight Nail Ltd | Other services | 2025 |
| Moores Accountancy Limited | Professional & scientific | 2013 |
| Moorland & City Railways Limited | Transport & logistics | 2009 |
| Moorland Motorcycle Hire Limited | Administrative & support | 2025 |
| Morbros Property Limited | Construction | 2022 |
| More Than Just Design Limited | Professional & scientific | 2014 |
| Moseleys Yard Residents Company Limited | Households | 2006 |
| Motor Essentials Ltd | Wholesale & retail | 2025 |
| Motortime Limited | Wholesale & retail | 2018 |
| Mount Square Management Company (Leek) Limited | Real estate | 2011 |
| Mountford Jones Homes Ltd | Construction | 2025 |
| Mountford Jones Talent Limited | Arts & recreation | 2025 |
| Mountford Trading Limited | Transport & logistics | 2025 |
| Mourne Brickwork Ltd | Construction | 2025 |
| Mourne Community Arts C.I.C. | Education | 2026 |
| Mourne Competitions Ltd | Wholesale & retail | 2024 |
| Mourne Fire & Electrical Ltd | Construction | 2026 |
| Mourne Gastronomy Ltd | Hospitality | 2018 |
| Mourne Heritage Trust-The | Professional & scientific | 1997 |
| Mourne Insulation Limited | Construction | 2024 |
| Mourne Kitchens & Interiors Ltd | Manufacturing | 2026 |
| Mourne Lettings Ltd | Hospitality | 2015 |
| Mourne Mountain Rescue Team | Health & social care | 2013 |
| Mourne Shack Limited | Wholesale & retail | 2020 |
| Mourneview Optical Ltd | Manufacturing | 2015 |
| Move Management Asset Removals Limited | Administrative & support | 2014 |
| Move Media (UK) Ltd | Arts & recreation | 2013 |
| Moveplus Property Limited | Real estate | 2023 |
| MPH Karting Academy Ltd | Arts & recreation | 2020 |
| MPH Motorsport Fitness Ltd | Arts & recreation | 2023 |
| MPH Motorsport Group Ltd | Arts & recreation | 2020 |
| MR Escalator Services Ltd | Professional & scientific | 2021 |
| MR Properties Midlands Limited | Real estate | 2018 |
| MR Radiography Ltd | Health & social care | 2021 |
| MR Spooner's Ltd | Professional & scientific | 2022 |
| Mrbana Ltd | Hospitality | 2023 |
| MRC Corporate Ltd | Professional & scientific | 2021 |
| MRC Holdings (Staffs) Limited | Financial services | 2025 |
| MRC Print Limited | Professional & scientific | 2017 |
| Mrrrt Limited | Wholesale & retail | 2023 |
| MRT Insulations Ltd | Manufacturing | 2014 |
| MS Taxi Cabs Limited | Transport & logistics | 2021 |
| MS4SM Limited | Wholesale & retail | 2015 |
| MSR Intl Holdings Ltd | Real estate | 2025 |
| MSR Products U.K Ltd | Extraterritorial | 2015 |
| MT Automation Limited | Professional & scientific | 2022 |
| MUB Accountants Ltd | Professional & scientific | 2020 |
| MUB Traders Ltd | Wholesale & retail | 2025 |
| Muhammad Orhan Ltd | Wholesale & retail | 2024 |
| Multicultural UK Ltd | Administrative & support | 2018 |
| Mumbai Blue Ltd | Hospitality | 2025 |
| Murlough Court Limited | Households | 2002 |
| Murlough Developments Ltd | Construction | 2021 |
| Murlough House | Hospitality | 2011 |
| MVC SCS Ltd | Information & communication | 2016 |
| MVM Vehicles Ltd | Professional & scientific | 2026 |
| Mvrv Investments Ltd | Real estate | 2026 |
| Mvrv Medical Services Private Ltd | Health & social care | 2019 |
| MW Website Design Ltd | Other services | 2025 |
| MWD Holdings Limited | Financial services | 2026 |
| My English Rose Ltd | Arts & recreation | 2015 |
| My Simple Mortgage Ltd | Financial services | 2014 |
| My Team Giordana Limited | Wholesale & retail | 2007 |
| Mybeam Ltd | Professional & scientific | 2020 |
| Mymoon Limited | Information & communication | 2019 |
| MYPLUMBER4U Ltd | Construction | 2017 |
| Myskin Store Ltd | Other services | 2024 |
| Myva Holdings Limited | Financial services | 2021 |
| Myva Properties Limited | Real estate | 2021 |
| N & P Cleaning Agency Limited | Administrative & support | 2011 |
| N Fitzgerald Limited | Hospitality | 2015 |
| N Plant Holdings Limited | Financial services | 2025 |
| N&K Fast Food Ltd | Hospitality | 2025 |
| N&M Leisure Ltd | Hospitality | 2018 |
| N&S Brough Ltd | Construction | 2018 |
| Nacrogate Limited | Other services | 1988 |
| Nail Glamour Ltd | Other services | 2025 |