| Mike Brewer Motoring Limited | Professional & scientific | 2020 |
| Mike Neal Garages Limited | Wholesale & retail | 2015 |
| Miklek Limited | Manufacturing | 2023 |
| Milanet Limited | Administrative & support | 2019 |
| Milano Market Ltd | Wholesale & retail | 2022 |
| Milestone Motors Limited | Wholesale & retail | 2009 |
| Mili Capital Limited | Real estate | 2025 |
| Millat Food Limited | Hospitality | 2025 |
| Millenia Fitness Ltd | Arts & recreation | 2020 |
| Millenia Fitness Online Ltd | Arts & recreation | 2024 |
| Millenium First Care Ltd | Health & social care | 2015 |
| Millennium Care West Yorkshire Limited | Extraterritorial | 2004 |
| Millennium Support Limited | Health & social care | 2004 |
| Miller & Nicholls Earthworks Ltd | Construction | 2026 |
| Miller Earthworks Limited | Professional & scientific | 2025 |
| Miller Geomatics Ltd | Construction | 2024 |
| Millfields (Ossett) Maintenance Limited | Households | 1984 |
| Millroyd Mill Management Company Limited | Real estate | 2012 |
| Milly Griffiths Ltd | Information & communication | 2019 |
| Milly MAY Media Ltd | Professional & scientific | 2026 |
| Milne Advice Holdings Limited | Financial services | 2025 |
| Milner Solutions Ltd | Other services | 2017 |
| Milnes Gaskell Catering Ltd | Hospitality | 2023 |
| Milnethorpe Property Management Limited | Real estate | 2020 |
| Milnthorpe Design Limited | Professional & scientific | 2003 |
| Milton Westfield Limited | Real estate | 2003 |
| Mimik Consultancy Ltd | Hospitality | 2024 |
| Mina Valeting Limited | Administrative & support | 2023 |
| Minchenden Consulting Ltd | Professional & scientific | 2020 |
| Mindfield Biosystems Ltd. | Manufacturing | 2003 |
| Mindfit Community Project C.I.C. | Health & social care | 2025 |
| Mindset Performance Ltd | Professional & scientific | 2012 |
| Mini Maestros Limited | Arts & recreation | 2007 |
| Mini Nail Bar Ltd | Other services | 2019 |
| Minpot Invests Ltd | Hospitality | 2020 |
| Minster Gelato Ltd | Manufacturing | 2025 |
| Minster Law Limited | Professional & scientific | 2003 |
| Minstone Limited | Professional & scientific | 2025 |
| Mint (Nails and Beauty) Limited | Other services | 2004 |
| Mint Autos of Wakefield Limited | Wholesale & retail | 2012 |
| Mint Bars Ltd | Hospitality | 2019 |
| Mint HR Limited | Administrative & support | 2016 |
| Mint Look Ltd | Professional & scientific | 2020 |
| Mint Nail and Beauty Bar LLP | | 2006 |
| Mint Sports Solutions Ltd | Administrative & support | 2016 |
| Mint Support Ltd | Other services | 2012 |
| Mirfield Construction Limited | Construction | 2002 |
| Mirfield Upholstery Ltd | Manufacturing | 2022 |
| Misaki Consultancy Limited | Professional & scientific | 2024 |
| Misbahazeem Limited | Wholesale & retail | 2022 |
| Mishratha Ltd | Real estate | 2019 |
| Mistry Paaske Limited | Health & social care | 2020 |
| Mitch-Hall Investments Ltd | Real estate | 2026 |
| Mitchell & Co (Electrical) Limited | Construction | 2001 |
| Mitchell & Co Holdings Ltd | Construction | 2017 |
| Mitchell & Hargreaves Ltd | Construction | 1978 |
| Mitchell (Holdings) Limited | Financial services | 2006 |
| Mito.To Ltd | Information & communication | 2020 |
| Mivi Consulting Limited | Financial services | 2016 |
| Mizzika 555 Ltd | Wholesale & retail | 2018 |
| MJ Cover Limited | Financial services | 2025 |
| MJC IT Services Ltd | Information & communication | 2025 |
| MJF Holdings Limited | Extraterritorial | 2003 |
| MJI Contractors Ltd | Construction | 2024 |
| MJK Law Limited | Extraterritorial | 2008 |
| MJL Joinery Limited | Construction | 2026 |
| MJM (Barnsley) Limited | Transport & logistics | 2016 |
| MJM Consulting Engineers Limited | Professional & scientific | 1996 |
| Mjmc (Consultants) Limited | Professional & scientific | 1996 |
| Mjmc (Holdings) Limited | Professional & scientific | 1996 |
| Mjmd Property Ltd | Real estate | 2026 |
| MJR Universe Logistic Ltd | Transport & logistics | 2019 |
| MJS Fencing and Waste Removals Ltd | Water & waste | 2019 |
| MJW Contractors Ltd | Construction | 2019 |
| MK Maintenance Yorkshire Ltd | Construction | 2026 |
| MK Properties (PVT) Ltd | Real estate | 2024 |
| MK2 Coverings Ltd | Manufacturing | 2019 |
| MKB Packaging Ltd | Administrative & support | 2024 |
| MKB Storage and Distribution Ltd | Transport & logistics | 2023 |
| MKD Plumbing & Heating Ltd | Construction | 2021 |
| MKK Converting Services Ltd | Administrative & support | 2020 |
| MKK Engineering Services Ltd | Manufacturing | 2016 |
| MKK Flexibles Ltd | Transport & logistics | 2025 |
| MKK Group Holdings Limited | Financial services | 2025 |
| MKK Machining and Fabrication Ltd | Manufacturing | 2019 |
| MKK Palletaxis Ltd | Transport & logistics | 2026 |
| MKM Broadcast Ltd | Information & communication | 2015 |
| MKW Holdings Limited | Financial services | 2017 |
| MKZ Food Management Consultancy Ltd | Professional & scientific | 2025 |
| ML AI Ltd | Information & communication | 2020 |
| ML Badges & More Limited | Wholesale & retail | 2003 |
| ML Joinery & Home Improvements Limited | Manufacturing | 2020 |
| Mlmcn Limited | Hospitality | 2023 |
| MM Verwaltung Ltd. | Professional & scientific | 2005 |
| MMA Medical Ltd | Health & social care | 2021 |
| MMC Business Management Limited | Professional & scientific | 2009 |
| MMC Real Estate Management Limited | Professional & scientific | 2009 |
| MMH Medicare Limited | Health & social care | 2026 |
| Mmjs EB Limited | Arts & recreation | 2009 |
| MMK Wand & Boden Ltd. | Construction | 2009 |