| Merdici Ltd | Professional & scientific | 2025 |
| Mere Hall Estates Ltd | Construction | 2012 |
| Mere Marketing LLP | | 2013 |
| Mereside Land Ltd. | Administrative & support | 2016 |
| Merestone Westminster Ltd | Real estate | 2026 |
| Merge Community Ltd | Administrative & support | 2025 |
| Merlin Park Limited | Administrative & support | 2012 |
| Merlin Repair Specialist Limited | Construction | 2008 |
| Merlin TAS UK Ltd | Professional & scientific | 2021 |
| Merriechem Limited | Administrative & support | 2011 |
| Merritt Diagnostics Ltd | Professional & scientific | 2025 |
| Merritt Medical Writing Ltd | Professional & scientific | 2023 |
| Mersey Analytical Services Ltd | Professional & scientific | 2010 |
| Mersey Networks Limited | Information & communication | 2026 |
| Mersey Security Systems Limited | Administrative & support | 2025 |
| Mersey Valley Golf and Country Club Limited | Construction | 1991 |
| Mersey View Pleasure Grounds Limited | Hospitality | 1942 |
| Mersix Solutions Ltd | Administrative & support | 2007 |
| Merville Quay Ltd | Administrative & support | 2026 |
| Mesan Ltd | Administrative & support | 2024 |
| Messi Creative Ltd | Professional & scientific | 2019 |
| Metagen Limited | Wholesale & retail | 2025 |
| Metal-Kraft Design Limited | Manufacturing | 2007 |
| Metalflex Industrial Supplies Holdings Limited | Financial services | 2025 |
| Metalfloor UK Holdings Limited | Financial services | 2025 |
| Metalfloor UK Limited | Construction | 2012 |
| Metamatrix Solutions Limited | Administrative & support | 2024 |
| Metcalfe Car Engineering Limited | Administrative & support | 2015 |
| Metcalfe Property Investment Limited | Real estate | 2020 |
| Method in the Marketing Ltd | Administrative & support | 2024 |
| Metier Management Services Ltd | Professional & scientific | 2011 |
| Metmat Forensics Limited | Professional & scientific | 2026 |
| Metocean Hub Limited | Professional & scientific | 2017 |
| Metric Project Solutions Ltd | Construction | 2024 |
| Metrics Maturity UK Ltd | Information & communication | 2021 |
| Metrix Projects Ltd | Administrative & support | 2007 |
| Metro Hosting Ltd | Information & communication | 2015 |
| Metrolux Bowls Ltd | Wholesale & retail | 2015 |
| Metropumps Limited | Manufacturing | 2023 |
| Metrx Group Limited | Administrative & support | 2025 |
| Metwire Belts Limited | Manufacturing | 1975 |
| Mezopotamia Limited | Wholesale & retail | 2025 |
| MF Building Services Management Limited | Professional & scientific | 2023 |
| MF Smith Consulting Ltd | Professional & scientific | 2006 |
| Mfab Limited | Other services | 2017 |
| MFD Logistics Ltd | Transport & logistics | 2023 |
| Mfdp Ltd | Administrative & support | 2022 |
| Mfdp Services Limited | Administrative & support | 2025 |
| MFM Consulting Services Limited | Construction | 2008 |
| MFS Design Limited | Construction | 2016 |
| MG Aggregates NW Limited | Wholesale & retail | 2024 |
| MG Cheshire Technology Limited | Information & communication | 2023 |
| MG Civil Engineering NW Limited | Construction | 2024 |
| MG Groundworks NW Limited | Construction | 2024 |
| MG Holdings NW Limited | Financial services | 2024 |
| MG Plant NW Limited | Administrative & support | 2024 |
| MGA Group Services UK Limited | Construction | 2005 |
| MGA North West Holdings Limited | Financial services | 2018 |
| MGB Estates Limited | Real estate | 2022 |
| MGB Security Ltd | Administrative & support | 2025 |
| Mgci Ltd | Administrative & support | 2025 |
| Mgdb Estates Limited | Real estate | 2024 |
| MGR Software Ltd | Information & communication | 2024 |
| MGS Glad Wood Ltd | Construction | 2018 |
| MGS Textiles Limited | Other services | 2013 |
| MH Inspection Services Ltd | Construction | 2024 |
| MH Predictive Maintenance Ltd | Professional & scientific | 2021 |
| Mhall.Xyz Ltd | Other services | 2018 |
| MHB Financial Planning Limited | Professional & scientific | 2023 |
| MHK Law Consultants Limited | Other services | 2019 |
| Mhnk Associates Limited | Administrative & support | 2014 |
| MHP Lock Ltd | Manufacturing | 2025 |
| MHS Imaging Ltd | Health & social care | 2011 |
| MHW Power Services Limited | Administrative & support | 2014 |
| MI Bakery Ltd | Manufacturing | 2023 |
| MI East Market Ltd | Wholesale & retail | 2024 |
| MI Right Home Limited | Real estate | 2018 |
| MI Tech Consultancy Ltd | Administrative & support | 2026 |
| MIA Richard Ltd | Wholesale & retail | 2023 |
| Miacci Ltd | Professional & scientific | 2020 |
| Mianmeer GB Ltd | Hospitality | 2020 |
| Miarose Hair & Cosmetics Ltd | Other services | 2019 |
| Mia’Smarketing Limited | Professional & scientific | 2025 |
| Mibo Health and Happiness Care Limited | Health & social care | 2023 |
| Mic-Law Integrated Consultancy Ltd | Administrative & support | 2026 |
| Michael Aspinall Ltd | Administrative & support | 2025 |
| Michael Birrell Consultancy Limited | Other services | 2017 |
| Michael Johnson Engineering Ltd | Administrative & support | 2025 |
| Michael Porter Landscapes Ltd | Administrative & support | 2022 |
| Michael Schmool Therapy Ltd | Health & social care | 2024 |
| Michael Waldron Limited | Professional & scientific | 2025 |
| Michelle Elizabeth Aesthetics Limited | Other services | 2025 |
| Michelle Molyneux Business Consulting Ltd | Professional & scientific | 2023 |
| Michley Consulting Limited | Administrative & support | 2024 |
| Mick Rail Limited | Other services | 2015 |
| Mickledore Limited | Professional & scientific | 2008 |
| Mico Spedition Ltd | Transport & logistics | 2019 |
| Micro Systems (UK) Limited | Manufacturing | 2002 |
| Micro-C Designs Limited | Information & communication | 1997 |
| Micro-Renewable Solutions Limited | Construction | 2010 |