| MBA Property Sales & Lettings Limited | Real estate | 2016 |
| Mcduff & Co. Properties Ltd. | Real estate | 2021 |
| Mcfee PUB Rescue Ltd | Hospitality | 2023 |
| Mcgregor Parry Limited | Professional & scientific | 2018 |
| Mchale Utility Services Limited | Construction | 2006 |
| Mcjunkin Red MAN UK Ltd | Professional & scientific | 2009 |
| MD Infinite Properties Limited | Real estate | 2023 |
| MDA SDA UK Limited | Wholesale & retail | 2014 |
| Medtech Commercial Advisory Ltd | Professional & scientific | 2026 |
| Mega City One Limited | Other services | 2002 |
| Mega Products Ltd | Manufacturing | 2026 |
| Megx Consultancy Ltd | Professional & scientific | 2023 |
| Meister Property Services Ltd | Real estate | 2025 |
| Mellor Yorkshire Services Ltd | Other services | 2021 |
| Meltham Wragg Limited | Construction | 2019 |
| Meltham Wragg Property Limited | Real estate | 2020 |
| Memp MAN Ltd | Real estate | 2018 |
| Mermaid Fish and Chips Ltd | Hospitality | 2019 |
| MH Build Ltd | Construction | 2019 |
| Michael George Manufacturing Limited | Manufacturing | 2009 |
| Michael LEE Consultants Ltd | Professional & scientific | 2022 |
| Michael Wright & SON Ltd | Other services | 2014 |
| Midland Holdings (Yorkshire) Limited | Real estate | 2016 |
| Miles Property Group Limited | Real estate | 2019 |
| Milestone Ripponden Ltd | Hospitality | 2024 |
| Mill Valley Brewery (Northern) Ltd | Manufacturing | 2022 |
| Milo Tools Limited | Wholesale & retail | 2014 |
| Mirfield Agricultural Show Society Limited | Other services | 2012 |
| Mirfield Bathrooms & Kitchens Limited | Construction | 2024 |
| Mirfield Development Company Limited | Construction | 1989 |
| MJD Real Estate Ltd | Real estate | 2019 |
| MKC Stores Ltd | Administrative & support | 2024 |
| MKL Property Services Ltd | Households | 2025 |
| MKM Building Contractors Limited | Administrative & support | 2017 |
| Mlvh Ltd | Hospitality | 2006 |
| MMH Contracting Ltd | Construction | 2019 |
| Molly's Pizza Limited | Extraterritorial | 2013 |
| Moon Bros Ltd | Real estate | 2024 |
| Moondance Consultants Ltd | Professional & scientific | 2016 |
| Moorland Minerals & Waste Limited | Professional & scientific | 2025 |
| Moortop Properties Ltd | Real estate | 2022 |
| Moraventures Limited | Professional & scientific | 2025 |
| More Bees Please Candle Company Ltd | Manufacturing | 2020 |
| Moreton Deakin Construction Ltd | Construction | 2021 |
| Moreton Deakin Holdings Limited | Financial services | 2021 |
| Morform Formwork & Concrete Limited | Construction | 2024 |
| Morform Group Holdings Limited | Financial services | 2025 |
| Morland-Austin Limited | Administrative & support | 2013 |
| Mors Forensics Ltd | Professional & scientific | 2015 |
| Motivate Limited | Real estate | 2026 |
| Move UP North Ltd | Real estate | 2024 |
| Movin'On Life and Health Coaching Ltd | Health & social care | 2025 |
| Moving Made Easy (Huntingdon) Limited | Real estate | 2016 |
| MR Mould Ltd | Wholesale & retail | 2024 |
| MR Nostalgia Limited | Manufacturing | 2018 |
| MR Tyre Cleckheaton Ltd | Wholesale & retail | 2020 |
| MR2 Motorsport Ltd | Wholesale & retail | 2022 |
| MRC Global (UK) Limited | Wholesale & retail | 1997 |
| MRC Transmark Holdings UK Limited | Professional & scientific | 2005 |
| MRE Property Solutions Limited | Real estate | 2021 |
| MS Engineering (Motorsport) Limited | Wholesale & retail | 2015 |
| MSB Metal Services Limited | Manufacturing | 2016 |
| MU Outlets Limited | Wholesale & retail | 2024 |
| MUD Island Real Estate Limited | Real estate | 2021 |
| Mulenshi & Oyebade Ltd | Hospitality | 2024 |
| MV Ductwork (Leeds) Limited | Extraterritorial | 2009 |
| My Direct Marketing Solutions Ltd | Wholesale & retail | 2023 |
| My Little NUT Tree and Co Ltd | Wholesale & retail | 2022 |
| My Logistics Holdings Limited | Financial services | 2023 |
| My Logistics Limited | Transport & logistics | 2005 |
| My Property Expert Ltd | Real estate | 2021 |
| Mymama Limited | Wholesale & retail | 2020 |
| Mystic Nook Ltd | Wholesale & retail | 2026 |
| N3 Solutions Ltd | Professional & scientific | 2023 |
| National Medicaid Limited | Health & social care | 2020 |
| Nautilus North Limited | Professional & scientific | 2024 |
| Navigate Talent Limited | Administrative & support | 2018 |
| NB Digital Ltd | Professional & scientific | 2014 |
| NC Leisure Limited | Hospitality | 2024 |
| NC Seating Services Limited | Administrative & support | 2016 |
| Ndpl Homes Limited | Real estate | 2018 |
| Ndpl UK Limited | Wholesale & retail | 2019 |
| Neom Recruitment Limited | Administrative & support | 2020 |
| Neptune Environmental Services Limited | Professional & scientific | 2006 |
| Nestara Living Limited | Real estate | 2025 |
| Network Commercial Holdings Ltd | Financial services | 2025 |
| Network Residential Property Ltd | Real estate | 2025 |
| New Gaff Property Ltd | Real estate | 2023 |
| New Island Properties Limited | Real estate | 2022 |
| New Slate Limited | Real estate | 2018 |
| New Stone Agri Limited | Construction | 2025 |
| New York Appartments Ltd | Real estate | 2021 |
| New-Seal Gasket Ltd | Manufacturing | 2011 |
| Newby Property Ltd | Real estate | 2026 |
| Newseal Finance Limited | Financial services | 2011 |
| NGL Estates Limited | Real estate | 2021 |
| NGS Investments Limited | Real estate | 2002 |
| NGS Motors Limited | Wholesale & retail | 1999 |
| NH Car & Commercial Vehicle Repaires Ltd | Wholesale & retail | 2010 |
| NH Residential Investments Ltd | Administrative & support | 2025 |