| Macnel Decorating Services Limited | Construction | 2025 |
| Macorp Limited | Wholesale & retail | 2012 |
| Madg Limited | Wholesale & retail | 2014 |
| Madof Ltd | Wholesale & retail | 2019 |
| Madruzzo Limited | Administrative & support | 2019 |
| Maed Management Ltd | Professional & scientific | 2025 |
| Magbag Industries Ltd | Water & waste | 2024 |
| Magcol Ltd | Households | 2024 |
| Magic BBQ Ltd | Hospitality | 2025 |
| Magistrates Market Ltd | Wholesale & retail | 2018 |
| Maharohithmitra Ltd | Wholesale & retail | 2025 |
| Mahmood Local Stores Ltd | Wholesale & retail | 2024 |
| Main Sequence Projection Domes Ltd | Manufacturing | 2012 |
| Mainline Freight Limited | Manufacturing | 2019 |
| Maintrad Limited | Real estate | 2017 |
| Maisie LOU Studio Ltd | Other services | 2025 |
| Majestic Kreations Limited | Wholesale & retail | 2024 |
| Majestic Worldwide Limited | Wholesale & retail | 2018 |
| MAK Takeaway Ltd | Hospitality | 2025 |
| Malachi Care Services Ltd | Health & social care | 2011 |
| Mallinders Limited | Wholesale & retail | 2025 |
| Mammabase Limited | Hospitality | 2020 |
| Mane Hairdressing (Pontefract) Limited | Other services | 2009 |
| Mane Pontefract Ltd | Other services | 2024 |
| Mannington Dental Limited | Health & social care | 2020 |
| Manor Farm Occasions and Therapists Ltd | Hospitality | 2024 |
| Manor Farm Spa Limited | Hospitality | 2019 |
| Mantis Packaging Ltd | Administrative & support | 2024 |
| Mantle Core Ventures Limited | Information & communication | 2025 |
| Mantle Web Development Limited | Information & communication | 2019 |
| Manto Enterprises Yorkshire Limited | Real estate | 2025 |
| Maple Drainage Limited | Water & waste | 2017 |
| March Cold Stores Limited | Professional & scientific | 1989 |
| Mario Prime Vent Ltd | Construction | 2026 |
| Mario's Mini Market Limited | Wholesale & retail | 2023 |
| Maris Asset Holdings Ltd | Real estate | 2026 |
| Maris Logistics Ltd | Transport & logistics | 2018 |
| Maris Properties Group Ltd | Real estate | 2026 |
| Mark Car Sales Ltd | Wholesale & retail | 2024 |
| Mark Mason Accountancy Limited | Professional & scientific | 2013 |
| Mark Rust Consultancy Ltd | Professional & scientific | 2024 |
| Marketiva Limited | Information & communication | 2024 |
| Marpop Transport Ltd | Transport & logistics | 2022 |
| Marra Made Ltd | Manufacturing | 2025 |
| Marsh Glazing Windows & Doors Limited | Construction | 2017 |
| Martic 79 Ltd | Construction | 2015 |
| Masala Room Ltd | Hospitality | 2025 |
| Masayimoyo Ltd | Health & social care | 2013 |
| Masda Properties Ltd | Real estate | 2024 |
| Masons Engineering Services Ltd | Professional & scientific | 2021 |
| Masons Property Management Ltd | Real estate | 2019 |
| Master Motorhomes Ltd | Wholesale & retail | 2021 |
| Masterlift Services Ltd | Construction | 2018 |
| Matilix Solutions Limited | Administrative & support | 2012 |
| Matthew Robert Clements Ltd | Real estate | 2022 |
| Matthew Whitworth Ltd | Wholesale & retail | 2025 |
| Matty Kelleher Joinery & Plumbing Ltd | Construction | 2017 |
| Mawahibu Ltd | Transport & logistics | 2023 |
| Mawson Trading Ltd | Wholesale & retail | 2025 |
| Maximum Pro Ltd | Wholesale & retail | 2023 |
| Maya's Takeaway Ltd | Hospitality | 2017 |
| Maygray Financial Consulting Limited | Professional & scientific | 2017 |
| Mayka Studio Ltd. | Professional & scientific | 2018 |
| Mayu Property Limited | Real estate | 2024 |
| MAZ Transport Services Limited | Transport & logistics | 2012 |
| MBC ITC Ltd | Information & communication | 2024 |
| MBD Transport Ltd | Transport & logistics | 2022 |
| MBP Civils Ltd | Construction | 2020 |
| MBT Compressed Air Ltd | Energy | 2025 |
| MCA Logistics-Transport Ltd | Transport & logistics | 2024 |
| MCE Storage Ltd | Real estate | 2024 |
| MCH Horticultural Construction Limited | Construction | 2014 |
| Mckenzie Pro Audio Limited | Manufacturing | 2008 |
| MD Planning Consulting Limited | Professional & scientific | 2018 |
| Mddh Limited | Professional & scientific | 2007 |
| Meadow Court Developments Ltd | Real estate | 2006 |
| Meadowfield Property Maintenance Ltd | Professional & scientific | 2000 |
| Meadowfield Village Homes Limited | Construction | 1993 |
| Meadows Tree Care Limited | Agriculture & fishing | 2025 |
| Mechanical,Electrical and Technical Engineering Ltd | Manufacturing | 2024 |
| Media 67 Ltd | Administrative & support | 2019 |
| Media Securities Limited | Other services | 2018 |
| Medichem (Pontefract) Limited | Wholesale & retail | 2011 |
| Meeko Limited | Professional & scientific | 2019 |
| Mellor Bathrooms & Plumbing Ltd | Construction | 2024 |
| Memory Messaging Limited | Information & communication | 2022 |
| Mena Transport Ltd | Transport & logistics | 2016 |
| Menooei Properties Ltd | Real estate | 2026 |
| Mercys Barbers Limited | Other services | 2018 |
| Meridian Group Diagnostics Ltd | Health & social care | 2026 |
| Merlin Co-Pack Ltd | Administrative & support | 2013 |
| Meta Access Solutions Limited | Construction | 2025 |
| Methley Scaffolding Services Limited | Construction | 2024 |
| MF T.G. International Ltd | Professional & scientific | 2011 |
| MFC Surveying Limited | Professional & scientific | 2015 |
| MG Follon Design Services Ltd | Professional & scientific | 2007 |
| MGD Property Maintenance Ltd | Construction | 2023 |
| Mgla Property Solutions Ltd | Real estate | 2023 |
| MGP Associates Ltd | Construction | 2013 |
| Michael Paul Scott Ltd | Extraterritorial | 2025 |