| Minster Roofing(York) Limited | Construction | 2017 |
| Minster Studies Ltd | Professional & scientific | 2003 |
| Minster Survey Limited | Construction | 2017 |
| Minster Veterinary Practice Ltd | Extraterritorial | 2006 |
| Minster Wills and Estate Planning Ltd | Professional & scientific | 2021 |
| Minster Wills Ltd | Extraterritorial | 2025 |
| MINSTER4 Limited | Real estate | 2024 |
| Minsterbuild Ltd | Construction | 2013 |
| Mint Cleaning Group Holdings Ltd | Administrative & support | 2017 |
| Mint Partnership Ltd | Professional & scientific | 2018 |
| Mint Square Limited | Professional & scientific | 2016 |
| Mint Wealth Management Limited | Financial services | 2010 |
| Mintagate Limited | Construction | 2016 |
| MIR Holiday Lettings Limited | Hospitality | 2025 |
| Mira Hair York Ltd | Other services | 2025 |
| Mirai Property Developments Ltd | Construction | 2024 |
| Mirchiz of York Ltd | Hospitality | 2018 |
| Mirham Ltd | Wholesale & retail | 2021 |
| Miriah Property Management Ltd | Real estate | 2026 |
| Miriventus Limited | Information & communication | 2012 |
| Mirkhel Leather Limited | Manufacturing | 2025 |
| Mirro Trans Limited | Transport & logistics | 2017 |
| Miss Brown's Bakery Limited | Wholesale & retail | 2004 |
| Miss Diva TOO Limited | Wholesale & retail | 2008 |
| Mister Vintique Limited | Wholesale & retail | 2019 |
| Miszka Ltd | Transport & logistics | 2022 |
| Miszkiel Capital Ltd | Financial services | 2026 |
| Mitch Tech Ltd | Construction | 2022 |
| Mitchell Business Services Limited | Administrative & support | 2003 |
| Mitchellmed UK Limited | Health & social care | 2019 |
| Mitchells Management Services Limited | Professional & scientific | 2004 |
| Mitrebuild Limited | Professional & scientific | 1972 |
| Mitrut Eyecare Limited | Health & social care | 2019 |
| Mits Griffin Ltd | Information & communication | 2022 |
| Mixa Limited | Hospitality | 2004 |
| MJ & EL Property Ltd | Real estate | 2025 |
| MJ Bowden Locations Ltd | Information & communication | 2008 |
| MJ Civil Engineering Ltd | Construction | 2015 |
| MJ Edmunds Limited | Professional & scientific | 2013 |
| MJ Gill Consulting Limited | Professional & scientific | 2008 |
| MJ Pearson Content Ltd | Professional & scientific | 2025 |
| MJF Detailing Limited | Wholesale & retail | 2025 |
| MJH Electrical York Ltd | Construction | 2024 |
| Mjhx Ltd | Real estate | 2020 |
| MJM Skip Hire Limited | Water & waste | 2026 |
| Mjpd Ltd | Real estate | 2018 |
| MJR York Limited | Professional & scientific | 2016 |
| MJS Hillcroft Limited | Hospitality | 2016 |
| MJS Telecoms Ltd | Professional & scientific | 2017 |
| MJS Yorkshire Limited | Financial services | 2011 |
| Mjturner E-Commerce Ltd | Wholesale & retail | 2022 |
| MJW (York) FD Consultancy Limited | Professional & scientific | 2024 |
| MJW Consult Ltd | Construction | 2022 |
| MJY Brickworks Ltd | Construction | 2023 |
| MK Healthcare & Aesthetics Ltd | Health & social care | 2024 |
| MK3D Ltd | Manufacturing | 2024 |
| MKC Management Services Ltd | Professional & scientific | 2019 |
| Mkhize Healthcare Limited | Health & social care | 2015 |
| Mkoz Limited | Health & social care | 2022 |
| ML Quality Properties Limited | Real estate | 2021 |
| ML Verify Ltd | Administrative & support | 2018 |
| ML Yorkshire Ltd | Hospitality | 2022 |
| MLA Tactical Solutions Limited | Professional & scientific | 2023 |
| MLA Universal Ltd | Professional & scientific | 2018 |
| MLB Electrical York Ltd | Construction | 2025 |
| MLB Properties York Ltd | Real estate | 2024 |
| MLC (York) Limited | Construction | 2007 |
| Mlhair Limited | Other services | 2014 |
| MLK Creative Limited | Financial services | 2022 |
| MLS Quality Properties Limited | Real estate | 2026 |
| Mltfl Limited | Health & social care | 2026 |
| MM & AM Ltd | Professional & scientific | 2007 |
| MM Car Parking Limited | Transport & logistics | 2018 |
| MM Holdings (Yorkshire) Limited | Real estate | 2022 |
| MMB Law Limited | Professional & scientific | 2013 |
| Mmgrowth Limited | Extraterritorial | 2015 |
| MMS Rail Systems Limited | Professional & scientific | 2016 |
| MMT Productions Ltd | Arts & recreation | 2016 |
| MND Fast Food Limited | Hospitality | 2017 |
| Mnme Ltd | Information & communication | 2026 |
| Mnml Offices Ltd | Real estate | 2021 |
| MNS Holdings Ltd | Financial services | 2015 |
| MO the Barber Ltd | Other services | 2018 |
| Moatfield Investments Limited | Real estate | 2016 |
| Mobile Cottage Ltd | Wholesale & retail | 2013 |
| Mobile Storage Systems Limited | Manufacturing | 1999 |
| Mobility Flow Ltd | Information & communication | 2022 |
| MOC Associates Ltd | Professional & scientific | 2024 |
| Mock Medic Limited | Information & communication | 2025 |
| Moda Developments Limited | Construction | 2003 |
| Mode Heating Ltd | Other services | 2025 |
| Mode Machinery Limited | Construction | 2020 |
| Model Farm Holiday Cottages Limited | Hospitality | 2022 |
| Model Railway Magic Ltd | Wholesale & retail | 2020 |
| Modelmatic Ltd | Wholesale & retail | 2016 |
| Modern Auctions Limited | Real estate | 2025 |
| Modern Water (U.K.) Limited | Administrative & support | 2024 |
| Modern Workplace Solutions Ltd | Information & communication | 2021 |
| Modernnook Ltd | Real estate | 2023 |
| Modimeld Limited | Information & communication | 2022 |