| Mcandrew Textiles Holdings Limited | Financial services | 2018 |
| Mccambridge Consulting Ltd | Information & communication | 2024 |
| Mccloy Lettings Ltd | Real estate | 2020 |
| Mcgillvary Properties Limited | Real estate | 2020 |
| Mcgillvary Sports Enterprise Limited | Arts & recreation | 2022 |
| Mcginty Mallowan & Co Ltd | Professional & scientific | 2021 |
| MCJ Services (Yorkshire) Ltd | Professional & scientific | 2011 |
| MCJ Trading Ltd | Wholesale & retail | 2022 |
| MCM Electrical Services and Property Maintenance Ltd | Construction | 2022 |
| MCM Medical Services Limited | Health & social care | 2023 |
| MCN Construction Limited | Construction | 2006 |
| MCN Construction Yorkshire Ltd | Construction | 2018 |
| MD Paint Inspections Limited | Professional & scientific | 2013 |
| MDF Investments Limited | Real estate | 2024 |
| MDH Dental Care Ltd | Health & social care | 2023 |
| MDH North Ltd | Real estate | 2021 |
| MDP Resources Limited | Wholesale & retail | 2020 |
| Me'N'U Arts Limited | Information & communication | 2007 |
| Meadowbank Farm York Limited | Agriculture & fishing | 2026 |
| Meadowbrook Electrical Limited | Energy | 2012 |
| Meadvale Vixon Ltd | Wholesale & retail | 2025 |
| Meandering Bear Ltd | Hospitality | 2019 |
| Mecca Film Developments Ltd | Information & communication | 2013 |
| Mech Solutions (Yorkshire) Ltd | Construction | 2021 |
| Medella Group Ltd | Wholesale & retail | 2020 |
| Medfit PVT Ltd | Manufacturing | 2024 |
| Media 8 Entertainment Limited | Other services | 2018 |
| Medici Comms Solutions Ltd | Professional & scientific | 2024 |
| Medina Abattoir Services Ltd | Manufacturing | 2023 |
| Medina Group Limited | Manufacturing | 2015 |
| Medina Meats Ltd | Wholesale & retail | 2024 |
| Mediquote Health Solutions Limited | Information & communication | 2002 |
| Medis Consultants Ltd | Wholesale & retail | 2023 |
| Medisense Medico-Legal Ltd | Health & social care | 2014 |
| Medlaw Advocates Ltd | Information & communication | 2023 |
| Medocal Ltd | Health & social care | 2019 |
| Mega Vibes Limited | Arts & recreation | 2012 |
| Megsons LLP | | 2006 |
| Megsons Personal Injury Limited | Professional & scientific | 2013 |
| Meimine Limited | Health & social care | 2013 |
| Mekhisla Ltd | Real estate | 2025 |
| Melville Rose Ltd | Wholesale & retail | 2025 |
| Memory Assessment Experts (MAE) Ltd | Health & social care | 2020 |
| Memory's Village Play Ltd | Hospitality | 2023 |
| Meon Walker Ltd | Wholesale & retail | 2025 |
| Mepsan UK Ltd | Manufacturing | 2025 |
| Mercer Associates Ltd | Information & communication | 2010 |
| Merino Tops Limited | Other services | 1997 |
| Meristem Arboriculture and Forestry Limited | Professional & scientific | 2020 |
| Merit Design & Services Limited | Manufacturing | 2015 |
| Merit Projects Limited | Manufacturing | 2002 |
| Merlin Design Bureau Ltd. | Professional & scientific | 2017 |
| Merlin Motorhomes Ltd | Manufacturing | 2016 |
| Merriman & SON Electrical Ltd | Construction | 2025 |
| Meshki UK Limited | Wholesale & retail | 2024 |
| MET Cleaning Services Limited | Administrative & support | 2024 |
| META4 Consulting Ltd | Information & communication | 2016 |
| Metaldyne International (UK) Ltd | Manufacturing | 1997 |
| Metallum Projects Ltd | Professional & scientific | 2020 |
| Metaltech (1997) Limited | Manufacturing | 2002 |
| Metaltech Holdings Limited | Financial services | 2024 |
| Metamorphos Ltd | Information & communication | 2025 |
| Metcalfe Enterprises Limited | Professional & scientific | 2016 |
| Meter Boost Limited | Financial services | 2020 |
| Mexi Bean Franchise Limited | Other services | 2024 |
| MF Law Ltd | Other services | 2018 |
| MFA Solutions Ltd | Transport & logistics | 2025 |
| MG Building Solutions (Yorkshire) Ltd | Construction | 2023 |
| MG Capital Finance Limited | Financial services | 2018 |
| MG Harrington Ltd | Health & social care | 2015 |
| MGD Building Ltd | Construction | 2022 |
| MGH Business Development Limited | Administrative & support | 2011 |
| Mgpr Merchandise Ltd | Wholesale & retail | 2024 |
| MH Automotive Ltd | Wholesale & retail | 2025 |
| MH North Ltd | Real estate | 2021 |
| MH Pharmaceuticals Ltd | Health & social care | 2024 |
| MH Trading (Yorkshire) Ltd | Wholesale & retail | 2021 |
| Mhaas Limited | Professional & scientific | 2025 |
| MHE (Halifax) Limited | Construction | 2000 |
| Mhet International Ltd | Other services | 2018 |
| MHG Property Ltd | Real estate | 2025 |
| Mhkp Ltd | Real estate | 2024 |
| MHM Services (GB) Limited | Wholesale & retail | 2006 |
| Mhsa Property Ltd | Real estate | 2025 |
| Mhth Limited | Real estate | 2015 |
| MI Pharmacare Limited | Health & social care | 2011 |
| MIA Estate Limited | Real estate | 2020 |
| Miaria Ltd | Wholesale & retail | 2025 |
| Michael Denton Associates Limited | Professional & scientific | 2008 |
| Michael Haigh & SON Ltd | Construction | 2018 |
| Michael Mallinson Limited | Agriculture & fishing | 1970 |
| Michael Mccarron Ltd | Professional & scientific | 2009 |
| Microbiome World Ltd | Health & social care | 2022 |
| Microform Precision Engineering Limited | Manufacturing | 2000 |
| Midgate Wheels Ltd | Wholesale & retail | 2025 |
| Midgley Chapel Management Company Limited | Households | 2016 |
| Midgley Joinery Services Ltd | Construction | 2025 |
| Midson Commercials Ltd | Wholesale & retail | 2025 |
| Mighty Digital Ltd | Professional & scientific | 2016 |
| Mighty Kids Supplements Ltd | Wholesale & retail | 2023 |