| Mbjm Developments Buffs Lane Ltd | Construction | 2021 |
| Mbjm Holdings Ltd | Professional & scientific | 2021 |
| MC Auto Solutions Limited | Professional & scientific | 2013 |
| Mcgrady Design Engineers Ltd | Administrative & support | 2011 |
| Mcgreal Properties Ltd | Real estate | 2025 |
| MDP Supplies Ltd | Wholesale & retail | 2000 |
| Media Maze Ltd | Extraterritorial | 2019 |
| Medicus Financial Planning Limited | Financial services | 2019 |
| Mere Property Group Limited | Professional & scientific | 2016 |
| Meridian Wirral Limited | Administrative & support | 2019 |
| Merseyside Plant Hire Limited | Administrative & support | 2001 |
| Metamorphosis Educational Consultancy Limited | Education | 2022 |
| Metrail Engineering Limited | Manufacturing | 1984 |
| Midland Building (North West) Limited | Construction | 2016 |
| Midland Group Limited | Construction | 2015 |
| Milbourne Estates Limited | Construction | 2004 |
| Mill UK Holdings 1 Limited | Financial services | 2013 |
| Mill UK Holdings 2 Limited | Financial services | 2013 |
| Mill UK Holdings 3 Limited | Financial services | 2013 |
| Mill UK Holdings 4 Limited | Financial services | 2013 |
| Mill UK Holdings 5 Limited | Financial services | 2013 |
| Millbrook Meadow Developments Holdings Limited | Financial services | 2021 |
| Millbrook Meadow Developments Limited | Construction | 2017 |
| Millbrook Paddock Limited | Construction | 2020 |
| Millipede Holdings Ltd | Professional & scientific | 2023 |
| Mimizan 1 Ltd | Real estate | 2024 |
| Mindarie Limited | Information & communication | 2014 |
| Mint Games Ltd | Information & communication | 2014 |
| Mississippi's Bar & Grill Limited | Hospitality | 2015 |
| MK Windoor Expert Limited | Professional & scientific | 2023 |
| MKW Project Delivery Ltd | Professional & scientific | 2022 |
| MNA Marine Services Limited | Transport & logistics | 2015 |
| Momentum Solutions Limited | Professional & scientific | 1998 |
| Moneyskills Group Limited | Administrative & support | 2007 |
| Monks Electrical Contractors Limited | Construction | 2009 |
| Montessori Designs Limited | Professional & scientific | 2020 |
| Monument Landscapes Ltd | Other services | 2009 |
| Moore Lifestyle Limited | Real estate | 2018 |
| Morgan MAI Stays Ltd | Real estate | 2023 |
| Morley Oak Limited | Real estate | 2017 |
| Morton Green Ltd | Extraterritorial | 2023 |
| Motorly Ltd | Extraterritorial | 2014 |
| Mountfield Property Lets Ltd | Households | 2019 |
| Moxie Works Limited | Administrative & support | 2016 |
| MPA Engineering Solutions Ltd | Professional & scientific | 2023 |
| MPH Autos Ltd | Wholesale & retail | 2021 |
| MR Adhd and Mental Health Consultancy Ltd | Health & social care | 2026 |
| MR EPC Limited | Manufacturing | 2024 |
| Mrce Limited | Administrative & support | 2018 |
| MSL Multiservice Limited | Construction | 2008 |
| MST Property Holdings Limited | Real estate | 2024 |
| Mulberry Web (Group) Limited | Real estate | 2019 |
| Murphy Consultants Limited | Professional & scientific | 2011 |
| Murray and Daughter Consulting Services Limited | Professional & scientific | 2025 |
| Murray Care Group Ltd | Health & social care | 2025 |
| Murray Care Poulton Ltd | Health & social care | 2024 |
| Murray Home Care Ltd | Health & social care | 2022 |
| MW Numech Ltd | Administrative & support | 2022 |
| My Benefits World Ltd | Public administration | 2016 |
| My Safety Folder Limited | Health & social care | 2017 |
| My World VIP Ltd | Administrative & support | 2016 |
| Myelin Diagnostics Limited | Health & social care | 2026 |
| N & L Collins Limited | Real estate | 2018 |
| N & P Windows (Wirral) Ltd | Manufacturing | 2004 |
| N J Townson Ltd | Construction | 2005 |
| N M P Engineering Limited | Professional & scientific | 2007 |
| N.J. Forman Limited | Professional & scientific | 2007 |
| Namsted Limited | Administrative & support | 2007 |
| Nazedyke Limited | Households | 1983 |
| NC Imaging Limited | Health & social care | 2026 |
| ND Williams Holdings Limited | Water & waste | 2017 |
| NDE Designs Limited | Administrative & support | 2007 |
| NDJ Engineering Services Limited | Professional & scientific | 2018 |
| NDK Inspection Services Limited | Professional & scientific | 2023 |
| Neena Swim Limited | Wholesale & retail | 2019 |
| Neil Farquhar Engineering Limited | Professional & scientific | 2007 |
| Neston Bathrooms Ltd | Construction | 2016 |
| Neston Building Supplies Limited | Wholesale & retail | 2015 |
| New Dawn Engineering Limited | Professional & scientific | 2007 |
| Newgen Networking Limited | Other services | 2020 |
| Nexus Dawn Limited | Professional & scientific | 2024 |
| Nexus Heritage - SRI Limited | Professional & scientific | 2008 |
| NGS Fibre Ltd | Construction | 2022 |
| Niall Bell Composite Engineering Limited | Professional & scientific | 2011 |
| Nimo Consult Ltd | Professional & scientific | 2010 |
| Nirvana Cosmetics Club Limited | Other services | 2018 |
| Noble HR Solutions Ltd. | Administrative & support | 2003 |
| Northwest Cladding and Refurbishment Limited | Construction | 2024 |
| Northwest Veins Limited | Health & social care | 2018 |
| Northyell Ltd | Construction | 2010 |
| NOT Yours! Rentals Limited | Real estate | 2024 |
| Nourish Natural Food Ltd | Hospitality | 2014 |
| Nsmc Property Management Limited | Real estate | 2017 |
| Nventures Ltd | Professional & scientific | 2006 |
| NW Facilities UK Ltd | Professional & scientific | 2021 |
| NW Glazing Solutions Ltd | Construction | 2018 |
| O & P Projects Limited | Construction | 2022 |
| O.B.A Property Group Ltd | Financial services | 2018 |
| Oak Developments (N.W.) Limited | Construction | 2003 |
| Oakley Carpentry & Joinery Limited | Construction | 2016 |