| M&R Rental Properties Ltd | Real estate | 2020 |
| MAC Lifting Solutions Limited | Construction | 2021 |
| MAC Medics Limited | Health & social care | 2017 |
| Mackintosh & Parker Electrical Contractors Limited | Construction | 2018 |
| MAD Dawg Media Limited | Manufacturing | 2011 |
| Maddocks & Sons Roofing Services Ltd | Construction | 2023 |
| Magic Upholstery Ltd | Other services | 2019 |
| MAI Accounts Management Ltd | Professional & scientific | 2012 |
| Maid in North Yorkshire Limited | Administrative & support | 2018 |
| Making Digital Real Ltd | Administrative & support | 2022 |
| Maldiva Leisure Limited | Administrative & support | 2021 |
| Mali Consultants Ltd | Professional & scientific | 2026 |
| Malpas House Ltd | Education | 2024 |
| Manor Home Farm Ltd | Agriculture & fishing | 2026 |
| Maple House Financial Management Limited | Financial services | 2009 |
| Maple Park (Hambleton) LLP | | 2021 |
| Marid Intelligence Ltd | Information & communication | 2025 |
| Marie Collins Foundation | Professional & scientific | 2011 |
| Marissa Leisure Limited | Hospitality | 2021 |
| Mark Baines Limited | Information & communication | 2014 |
| Mark Gibson Medicolegal Consultancy Limited | Health & social care | 2002 |
| Mark Wilkinson Joinery Limited | Construction | 2006 |
| Market Gate Residential Management Company Limited | Real estate | 2008 |
| Marksman Football Ltd | Arts & recreation | 2025 |
| Marr House Farm Limited | Transport & logistics | 2006 |
| Masden Limited | Hospitality | 2019 |
| Matthias Consulting Services Limited | Professional & scientific | 2019 |
| Maui Consulting Limited | Information & communication | 2025 |
| MCIVORS2020 Limited | Wholesale & retail | 2020 |
| MCL Woodseats Limited | Real estate | 2022 |
| Mclernon Services Limited | Other services | 2020 |
| Mcmahon Green Grocers Limited | Wholesale & retail | 2015 |
| Mcmahons Stokesley Ltd | Wholesale & retail | 2023 |
| MDB Ltd | Other services | 1990 |
| Meanwood Management Limited | Real estate | 2005 |
| Mech Part Limited | Wholesale & retail | 2026 |
| Melon Enterprise Limited | Manufacturing | 2022 |
| Meow Meow Beans Ltd | Hospitality | 2024 |
| Mera Design Limited | Wholesale & retail | 2025 |
| Merchant Place, Northallerton Management Limited | Households | 2019 |
| Merit Estates (Yorkshire) Limited | Real estate | 2017 |
| Methanex (UK) Limited | Professional & scientific | 2000 |
| MG & J Properties Ltd | Real estate | 2025 |
| Mickledale Land & Property Investments Limited | Construction | 2024 |
| Micro Chef Catering Ltd | Hospitality | 2022 |
| Midland Land Improvements Limited | Real estate | 2000 |
| Mike Webb Dive REP Ltd | Other services | 2014 |
| Milano Adhd and Neurodiversity Empowerment Ltd | Professional & scientific | 2024 |
| Mile House Vets Limited | Professional & scientific | 2014 |
| Milldora Projects Ltd | Transport & logistics | 2026 |
| Millennium Window Systems Ltd | Construction | 2016 |
| Miller Country Parks Limited | Hospitality | 2020 |
| Miller Leisure Homes Limited | Extraterritorial | 2023 |
| Mini Explorers Crabtree Limited | Health & social care | 2012 |
| Minicoach World Limited | Manufacturing | 2015 |
| Mj's Ice Cream Ltd | Wholesale & retail | 2025 |
| MM Electrical (Yorkshire) Limited | Construction | 2024 |
| Money Project Limited | Professional & scientific | 2009 |
| Monksfield Management Company Limited | Real estate | 2007 |
| Moody Construction Ltd | Construction | 1953 |
| Moon Star Nails & Beauty Ltd | Other services | 2026 |
| Moorcon Holdings Limited | Financial services | 2024 |
| Morton Grange Limited | Agriculture & fishing | 2009 |
| Morton Veterinary Consultancy Limited | Professional & scientific | 2017 |
| MOS Management Company Limited | Real estate | 2019 |
| Motorbikers Cosmetic Company Limited | Wholesale & retail | 2017 |
| Motorsport Direct Ltd | Wholesale & retail | 2022 |
| Motoscope (Northallerton) Limited | Wholesale & retail | 2003 |
| Mototest Limited | Wholesale & retail | 2015 |
| Mount Grace Charcuterie Ltd | Manufacturing | 2022 |
| Moving Cars Ltd | Other services | 2017 |
| Mowbray Solutions Limited | Information & communication | 2024 |
| Mowden Controls Limited | Manufacturing | 1965 |
| Mulberry Homes Yorkshire Limited | Construction | 2009 |
| Multistrip Limited | Administrative & support | 2008 |
| Multisure Limited | Wholesale & retail | 2004 |
| MW Editorial Design Limited | Professional & scientific | 2025 |
| Myco Foods Ltd | Manufacturing | 2016 |
| Myco Sustainable Ingredients Ltd | Manufacturing | 2025 |
| Myr@D Limited | Manufacturing | 2016 |
| N D Rowling Ltd | Other services | 2024 |
| N R H Car Wash Limited | Administrative & support | 2025 |
| N-Gate Limited | Administrative & support | 2001 |
| N.Y.G. Limited | Construction | 2002 |
| Nala Homes Ltd | Real estate | 2024 |
| National Cable Installations Limited | Hospitality | 2021 |
| NDF Property Consultants Limited | Real estate | 2021 |
| Neil Season Ltd | Hospitality | 2025 |
| Neon Dog Studios Ltd | Wholesale & retail | 2015 |
| Neon IT Services Ltd | Information & communication | 2022 |
| Neville J Gill Property Limited | Real estate | 2025 |
| New Life Baptist Church Northallerton | Health & social care | 2010 |
| New Life Garments Ltd | Administrative & support | 2017 |
| New Romanby House Limited | Hospitality | 2026 |
| New Wings Ltd | Health & social care | 2019 |
| Newland JEM Limited | Real estate | 1992 |
| Newlands (York) Holdings Limited | Financial services | 2026 |
| Newlands (York) Limited | Agriculture & fishing | 2018 |
| Newquip Limited | Wholesale & retail | 2005 |
| Next Best Clothing Limited | Wholesale & retail | 1998 |