| Macey Design Ltd | Other services | 2006 |
| MAD Value Ltd | Other services | 2020 |
| MADCAT3D Ltd | Professional & scientific | 2018 |
| Madison Spa Limited | Other services | 2008 |
| MAE Property Finance Ltd | Professional & scientific | 2014 |
| Magic Rags Cleaning Services Ltd | Administrative & support | 2023 |
| Maia Baby Ltd | Wholesale & retail | 2026 |
| Maid Better Ltd | Administrative & support | 2021 |
| Maintain Independence Ltd | Health & social care | 2024 |
| Maison DE Bois Ltd | Administrative & support | 2017 |
| Majorsight Limited | Construction | 1992 |
| Mako Commercial Interiors Ltd | Wholesale & retail | 2023 |
| Maksol Control Limited | Information & communication | 2008 |
| Maksymowicz Limited | Professional & scientific | 2018 |
| Maktub Consulting Ltd | Professional & scientific | 2020 |
| Malista Aroma Ltd | Hospitality | 2023 |
| Mango Meadow Ltd | Administrative & support | 2023 |
| Manor Court Management (Nantwich) Limited | Real estate | 2001 |
| Manor Farm Barns (Seven Sisters) Management Company Limited | Households | 2025 |
| MAP Horizon Ltd | Information & communication | 2025 |
| Marbury Properties (Chester) LLP | | 2007 |
| Marcus Leon Creative Ltd | Other services | 2009 |
| Mark Beavan Associates Limited | Administrative & support | 2009 |
| Mark D Harding Construction Ltd | Construction | 2025 |
| Mark Johnson Estate Agents Limited | Real estate | 2019 |
| Mark One Construction Services Ltd | Construction | 2011 |
| Marlin Developments Limited | Real estate | 1984 |
| Marquis Finance Ltd | Wholesale & retail | 2005 |
| Marquis Medical Limited | Health & social care | 2019 |
| Martin Renewables Solutions Limited | Professional & scientific | 2022 |
| Masons Build Ltd | Construction | 2016 |
| Masons Electrical Ltd | Construction | 2019 |
| MAT Industrial Services Limited | Construction | 1994 |
| Matthew Radcliffe Physio Consultancy Ltd | Health & social care | 2019 |
| MAV Marketing Limited | Extraterritorial | 2008 |
| Maven Marine Limited | Extraterritorial | 2016 |
| MAX MAY Construction Limited | Construction | 2024 |
| MAX MAY Properties Limited | Real estate | 2021 |
| Maxx- Bestwholesale Ltd | Wholesale & retail | 2025 |
| MAY Barn Horticultural Consultancy Ltd | Professional & scientific | 2011 |
| Mayanweb Consulting Ltd | Information & communication | 2007 |
| MC (Burton) Limited | Professional & scientific | 2013 |
| MCG Rentals Limited | Households | 2016 |
| Mcintyre Asset Finance Limited | Financial services | 2014 |
| Mcque Ltd | Real estate | 2005 |
| MDR Holdings Ltd | Extraterritorial | 2016 |
| Meadow Cheese (Processing) Limited | Manufacturing | 1999 |
| Meadow Grange Management Limited | Real estate | 2006 |
| Medq Consulting Ltd | Professional & scientific | 2023 |
| Mendy & Watt Financial Advisers Limited | Financial services | 2018 |
| Mendy & Watt Limited | Financial services | 2017 |
| Mental Health Charter C.I.C. | Administrative & support | 2020 |
| Meraki Modelling Limited | Professional & scientific | 2020 |
| Mercer Construction Services Ltd | Construction | 2024 |
| Merrill Home Maintenance Limited | Construction | 2014 |
| Merseyside Demolition & Marine Salvage Limited | Construction | 2009 |
| MF Security Ltd | Construction | 2018 |
| MGH Baber Limited | Other services | 2017 |
| MGH Corporation Limited | Financial services | 2021 |
| MGH Hairdressers Limited | Other services | 2026 |
| MGH Property Services Limited | Energy | 2020 |
| MI Soft Tissue Clinic Ltd | Health & social care | 2026 |
| MIA Stanza Limited | Wholesale & retail | 2002 |
| Mialo Limited | Hospitality | 2025 |
| MIC Properties Ltd | Real estate | 2019 |
| Michael Baddeley Holdings Limited | Transport & logistics | 2012 |
| Michael Doherty Limited | Professional & scientific | 2012 |
| Mick the Chips Ltd | Hospitality | 2026 |
| Mickley Corporation Limited | Arts & recreation | 2013 |
| Mideva Holdings Ltd | Construction | 2023 |
| Midland C.P Company Ltd | Real estate | 2023 |
| Midland Fuel OIL Supplies Limited | Wholesale & retail | 1988 |
| Midland R.P Company Ltd | Households | 2026 |
| Mike Guilliard Orthopaedics Limited | Professional & scientific | 2011 |
| Milania Ltd | Wholesale & retail | 2022 |
| Mill Street Developments Limited | Construction | 2022 |
| Miller Transport Holdings Limited | Financial services | 2023 |
| Millhurst Property LLP | | 2020 |
| Milvus Properties Limited | Real estate | 2018 |
| Mind Machine Ltd | Information & communication | 2024 |
| Minerals Marketing Limited | Wholesale & retail | 2005 |
| Minerals Marketing SJB Holdings Limited | Financial services | 2023 |
| Minshall & Co Limited | Professional & scientific | 2026 |
| Minshalls Limited | Construction | 2026 |
| Mintx Ltd | Manufacturing | 2026 |
| Missy's Beauty Limited | Other services | 2015 |
| Mitchell & Mitchell Limited | Financial services | 2026 |
| Mixie Investments Ltd | Real estate | 2023 |
| MJM Catering Ltd | Hospitality | 2025 |
| MLF Access Services Ltd | Construction | 2018 |
| MM Collective CIC | Education | 2020 |
| MM Landscaping & Groundworks Limited | Administrative & support | 2024 |
| Mo-Vine Health Limited | Health & social care | 2023 |
| Mobi Property Limited | Real estate | 2016 |
| Modern Villas Limited | Real estate | 1933 |
| Mollard Motors (Cheshire) Limited | Wholesale & retail | 2010 |
| Molyneux Brickwork Limited | Construction | 2016 |
| Momentum Coaching Limited | Professional & scientific | 2021 |
| Monika's Wilderness Ltd | Real estate | 2022 |
| Montita Limited | Other services | 2023 |