| Melius Ltd | Construction | 2019 |
| Melteq Limited | Wholesale & retail | 2012 |
| Meltham Balti Ltd | Hospitality | 2015 |
| Meltham Builders Limited | Construction | 1976 |
| Meltham Carbide Precision Ltd | Manufacturing | 2011 |
| Meltham Carlile Limited | Real estate | 2014 |
| Meltham Dental Care Limited | Administrative & support | 2010 |
| Meltham Financial Solutions LLP | | 2012 |
| Meltham Fisheries Ltd | Hospitality | 2020 |
| Meltham Food to Go Ltd | Hospitality | 2026 |
| Meltham Golf Club,Limited | Arts & recreation | 1947 |
| Meltham Grange Management Company Limited | Households | 2018 |
| Meltham Mill (Holdings) Limited | Financial services | 2022 |
| Meltham Pre-School Playgroup C.I.C. | Education | 2015 |
| Meltham Properties (2012) Limited | Real estate | 1999 |
| Meltham Properties (Holdings) Limited | Financial services | 2012 |
| Meltham Properties Group (2022) Limited | Financial services | 2022 |
| Meltham Properties Group Limited | Financial services | 2017 |
| Meltham Properties Limited | Real estate | 1999 |
| Meltham School's OUT | Health & social care | 2008 |
| Meltham Sports and Community Group Limited | Arts & recreation | 2002 |
| Meraki Stationery Ltd | Professional & scientific | 2019 |
| Merlin Motor Services Ltd | Wholesale & retail | 2017 |
| Methodist Youth Activities Limited | Other services | 1981 |
| MG Travel Ltd | Administrative & support | 2026 |
| MGH Software Ltd | Information & communication | 2026 |
| MGW Anaesthetics Limited | Health & social care | 2015 |
| Mhgc Investments Limited | Administrative & support | 2011 |
| Michael Dyson Associates (Asset Management) Ltd | Extraterritorial | 2024 |
| Michael Dyson Associates (Project Management) Ltd | Extraterritorial | 2024 |
| Mick Moorhouse Rigging Services Ltd | Information & communication | 2021 |
| Midway Barn Ltd | Real estate | 2025 |
| Mill Fold (Management) Limited | Households | 2004 |
| Mill Turn Solutions Limited | Manufacturing | 2017 |
| Miller & Straughan Construction Design Limited | Professional & scientific | 2017 |
| Millmead Health & Wellbeing Ltd. | Health & social care | 2014 |
| Millside Heating Limited | Construction | 2020 |
| Milly Finch Oncology Professional Services Limited | Health & social care | 2025 |
| Millytheink Limited | Arts & recreation | 2007 |
| Milnsbridge Properties Limited | Real estate | 2013 |
| Milonic Advanced Technologies Ltd | Wholesale & retail | 2015 |
| Mindora Health Ltd | Health & social care | 2026 |
| Mini Mansions Children's Homes Ltd | Health & social care | 2025 |
| Mini Motors Sensory Limited | Health & social care | 2024 |
| Mission Racing Limited | Administrative & support | 2007 |
| Missy Shutt-Vine Ltd | Administrative & support | 2020 |
| MJB Roofing Limited | Construction | 2014 |
| MJC Residential Limited | Real estate | 2011 |
| MJL Plumbing & Heating Services (North) Ltd | Construction | 2013 |
| Mjweb Ltd | Information & communication | 2020 |
| MLB Storage Limited | Administrative & support | 2024 |
| MM Convenience Store Ltd | Wholesale & retail | 2017 |
| Modern Work Foundation CIC | Administrative & support | 2016 |
| Modulus Precision Engineering Limited | Manufacturing | 2005 |
| Moll Springs Limited | Real estate | 2005 |
| Moll Springs Water Company Limited | Wholesale & retail | 2025 |
| Monarch Farms Limited | Agriculture & fishing | 2003 |
| Monarch Mobility Healthcare Ltd | Wholesale & retail | 2019 |
| Monarch Mobility Holdings Limited | Financial services | 2025 |
| Monarch Mobility International Limited | Manufacturing | 2025 |
| Monarch Mobility Limited | Manufacturing | 2001 |
| Moncreiff Medical Services Ltd | Health & social care | 2019 |
| Moon Cross Events Ltd | Administrative & support | 2022 |
| Moore Site Services Limited | Construction | 2024 |
| Moorlands Properties Ltd | Real estate | 2023 |
| Moorspace Storage Co Limited | Administrative & support | 2019 |
| Mordred Limited | Extraterritorial | 2010 |
| Morgan Milnes Tool Company Limited | Extraterritorial | 1961 |
| Morrisons Heating Services Ltd | Construction | 2018 |
| Mortgage to Home Ltd | Professional & scientific | 2021 |
| Moss Edge Farm Leisure Limited | Hospitality | 2022 |
| Motor Manifest Limited | Wholesale & retail | 2020 |
| Motorworks (UK) Limited | Administrative & support | 2010 |
| Mount Boiler Specialists Ltd | Construction | 2016 |
| Mount Packaging Systems Limited | Manufacturing | 1993 |
| Move Smooth Ltd | Real estate | 2025 |
| Move With Caroline Limited | Arts & recreation | 2025 |
| Mowwa Limited | Administrative & support | 2024 |
| MP Smart Services Limited | Professional & scientific | 2014 |
| Mp&E Plumbing & Heating Ltd | Construction | 2017 |
| MPH Building and Construction Limited | Construction | 2015 |
| MPW External Cleaning Services Ltd | Administrative & support | 2021 |
| MR and MRS Electrical Ltd | Construction | 2025 |
| MR Blue HD Ltd | Wholesale & retail | 2024 |
| MR Blue Holmfirth Ltd | Wholesale & retail | 2026 |
| Mrcgp Revision Limited | Education | 2026 |
| MSB Symposia Ltd | Real estate | 2022 |
| Mulberry Care Homes Limited | Health & social care | 2022 |
| Mulberry Developments (Yorkshire) Ltd | Construction | 2026 |
| Mulligan Builders (Yorkshire) Ltd | Construction | 2009 |
| Munchies Dessert Bar Ltd | Hospitality | 2023 |
| Munro Weed Control Limited | Other services | 2014 |
| Murgoyne Investments Limited | Real estate | 2017 |
| Muslin Hall Garage Limited | Wholesale & retail | 2004 |
| Muslin Hall Holdings Limited | Wholesale & retail | 2020 |
| MVS Research and Consulting Limited | Professional & scientific | 2013 |
| My DAD HAD One of Those Ltd | Transport & logistics | 2018 |
| N B Fabrics Limited | Manufacturing | 2009 |
| N Turner Joinery Contractors Limited | Construction | 1998 |
| Nanango Limited | Real estate | 2024 |