| Modivis Limited | Professional & scientific | 2025 |
| Modular Associates Limited | Professional & scientific | 2010 |
| Modular Buildings and Cabins Limited | Construction | 2022 |
| Modular R&D Limited | Professional & scientific | 2025 |
| Modular Scaffolding Yorkshire Limited | Construction | 2024 |
| Mogg Cottage Ltd | Real estate | 2025 |
| Mohammed Al-Naseri Limited | Health & social care | 2020 |
| Mohawk Associates Ltd | Professional & scientific | 2009 |
| Mojo York Ltd | Construction | 2018 |
| MOL Engineering Services Limited | Manufacturing | 2013 |
| Molecular Vision Limited | Professional & scientific | 2001 |
| Moliorgreen Architecture Limited | Professional & scientific | 2008 |
| Mollan & Co Accountants Ltd | Professional & scientific | 2007 |
| Mollie Coates Skelton Nurseries Limited | Wholesale & retail | 1985 |
| Molloy Science and Technology Ltd | Professional & scientific | 2022 |
| Molly Browns Holdings Limited | Real estate | 2022 |
| Molly Browns Limited | Wholesale & retail | 2017 |
| Molly DDS Dental Services Ltd | Health & social care | 2021 |
| Molly Lister Ltd | Information & communication | 2022 |
| Molly Rae's Limited | Other services | 2024 |
| MOM Developments Limited | Households | 2025 |
| Momentum Consulting Solutions Limited | Professional & scientific | 2025 |
| Momentum Financial Solutions Ltd | Administrative & support | 2010 |
| Mommygaroo Ltd | Wholesale & retail | 2022 |
| Momoh Services Ltd | Health & social care | 2019 |
| Mona & Sons Estates Ltd | Real estate | 2025 |
| Mona & Sons Ltd | Hospitality | 2023 |
| Mona & Sons Projects Ltd | Financial services | 2025 |
| Money Madness Competition Ltd | Wholesale & retail | 2025 |
| Monitor Holdings Limited | Financial services | 2021 |
| Monk Bar Apartments Limited | Real estate | 2025 |
| Monk Bar Chocolatiers Limited | Manufacturing | 2002 |
| Monk Bar York Limited | Real estate | 2025 |
| Monk Bridge Construction Company,Limited(The) | Construction | 1922 |
| Monk Homes Limited | Extraterritorial | 1988 |
| Monk Stray Properties Limited | Real estate | 1982 |
| Monk's Cross Property (Finance) Limited | Financial services | 2024 |
| Monkbar Mews Limited | Hospitality | 2022 |
| Monkbar Pharmacy Ltd | Health & social care | 2011 |
| Monkbridge Management Company Limited | Households | 1994 |
| Monkgate (York) Management Company Limited | Extraterritorial | 1984 |
| Monks Barn Limited | Real estate | 2019 |
| Monks Barn Properties LLP | | 2014 |
| Monks Cross (Investment) Limited | Real estate | 2024 |
| Monks Cross Manco Ltd | Real estate | 2025 |
| Monks Cross Property (Holding) Limited | Real estate | 2014 |
| Monks Ice Cream Ltd | Hospitality | 2024 |
| Monkswood (Sacriston) Management Company Limited | Real estate | 2019 |
| Monkton Motors Ltd | Wholesale & retail | 2014 |
| Mono Search Limited | Administrative & support | 2024 |
| Monroe Accountants Ltd | Professional & scientific | 2021 |
| Monsell Youell Construction Limited | Extraterritorial | 1970 |
| Monsell Youell Limited | Extraterritorial | 1969 |
| Monsieur K Clothing Alterations ( Bespoke Tailor ) Ltd | Other services | 2016 |
| Monster Chef Limited | Wholesale & retail | 2012 |
| Monster Group (UK) Limited | Wholesale & retail | 2007 |
| Monster Group Holdings Limited | Financial services | 2019 |
| Monster Group Property Limited | Real estate | 2019 |
| Monster Management LLP | | 2015 |
| Monster Maths Limited | Education | 2017 |
| Monster Payroll LLP | | 2015 |
| Monster Racking Limited | Wholesale & retail | 2012 |
| Montage Dynamics Limited | Professional & scientific | 2022 |
| Montague Developments Limited | Extraterritorial | 1961 |
| Montague Grove Limited | Real estate | 2024 |
| Montfold Limited | Households | 1981 |
| Montgomery Place (Frome) Management Company Ltd | Households | 2024 |
| Monti Consultants Ltd | Information & communication | 2026 |
| Monty Miracle Ltd | Professional & scientific | 2015 |
| MOO MOO Steakhouse Ltd | Hospitality | 2023 |
| Moo-York Ltd | Hospitality | 2022 |
| Moodymare Patisserie Ltd | Hospitality | 2024 |
| Mooflower Limited | Information & communication | 2010 |
| Moon Tran Ltd | Other services | 2017 |
| Mooncake Property Limited | Real estate | 2022 |
| Moondog Properties Ltd | Real estate | 2019 |
| Moone Enterprises Ltd | Administrative & support | 2014 |
| Moonglade Ltd | Manufacturing | 2019 |
| Moonrise Attic Ltd | Wholesale & retail | 2024 |
| Moor Allerton Securities Limited | Administrative & support | 1971 |
| Moor Farm Property Limited | Real estate | 2025 |
| Moor Farm Stables York Ltd | Administrative & support | 2004 |
| Moor Farm York Ltd | Wholesale & retail | 2017 |
| Moor Forge Press Limited | Arts & recreation | 2019 |
| Moor Galloway & Company ALD Ltd | Real estate | 2018 |
| Moor Galloway & Company Guisborough Ltd | Real estate | 2017 |
| Moor Galloway & Company Ltd | Real estate | 2015 |
| Moor Galloway & Company Park Road Ltd | Real estate | 2017 |
| Moor Galloway & Company Properties Ltd | Real estate | 2018 |
| Moor Lane Advisory Limited | Professional & scientific | 2026 |
| Moor Lane Autos Limited | Wholesale & retail | 2003 |
| Moor LYN Management Company Limited | Households | 2020 |
| Moor Valley Country Park Ltd | Hospitality | 1988 |
| Moorcaster Dales Limited | Professional & scientific | 2025 |
| Moorcroft Flats (York) Limited | Households | 1965 |
| Moorcroft Flats Limited | Real estate | 2018 |
| Moorcroft Service Station Ltd | Wholesale & retail | 2015 |
| Moore & Easterby Limited | Real estate | 2019 |
| Moore Building Enterprises Limited | Construction | 1995 |
| Moore Collectables Ltd | Wholesale & retail | 2025 |