| Mctt Probation Ltd | Information & communication | 2013 |
| MD Civils Ltd | Construction | 2022 |
| MD Energy Assessments Limited | Other services | 2023 |
| MD Roofing Specialists Ltd | Construction | 2025 |
| MD Scaffolding Solutions Ltd | Construction | 2020 |
| MDB (Group) Ltd | Financial services | 2014 |
| MDB Engineering Limited | Construction | 2003 |
| MDB Freehold Ltd | Real estate | 2014 |
| MDG Motors Limited | Wholesale & retail | 2025 |
| MDS Designs Ltd | Professional & scientific | 2023 |
| MDS Direct Windows Ltd | | 2008 |
| ME 2 YOU Light Haulage Limited | Transport & logistics | 2017 |
| Meadow Drive 1971 Limited | Administrative & support | 2015 |
| Meadow Meats Limited | Professional & scientific | 2007 |
| Meadows Therapy Group Ltd | Health & social care | 2023 |
| MEC Construct Ltd | Construction | 2023 |
| Meci Properties Ltd | Real estate | 2023 |
| Medi-Regs Consultancy Limited | Professional & scientific | 2017 |
| Medical Support Services 24 Hours Limited | Health & social care | 2013 |
| Meditecpro Limited | Wholesale & retail | 2025 |
| Mediterranean Deli Ltd | Wholesale & retail | 2024 |
| Medkar Limited | Transport & logistics | 2018 |
| Medusa Academy Hair and Beauty Ltd | Other services | 2026 |
| Meetcask Limited | Real estate | 1986 |
| Mega Delicious Limited | Hospitality | 2024 |
| Megram Kingdom Ltd | Administrative & support | 2021 |
| Megson Projects Ltd | Construction | 2025 |
| Meiduk Limited | Health & social care | 2025 |
| Melett Limited | Manufacturing | 2002 |
| Melfak Consulting Ltd | Professional & scientific | 2022 |
| Melfak Ltd | Professional & scientific | 2021 |
| Melissa Swan Social Work Ltd | Health & social care | 2021 |
| Memetkebab Ltd | Transport & logistics | 2025 |
| Meneh Homes Ltd | Real estate | 2025 |
| Mercia Image Ltd. | Manufacturing | 1994 |
| Mercury FF Ltd | Hospitality | 2022 |
| Merganser Properties Limited | Real estate | 1999 |
| Merit Maintenance Ltd | Administrative & support | 2019 |
| Merj Electrical Limited | Construction | 2024 |
| Merj Properties Limited | Real estate | 2025 |
| Merla Medical Limited | Health & social care | 2025 |
| Mero Property Ventures Limited | Real estate | 2024 |
| Merry Berry Property Investments Ltd | Real estate | 2025 |
| MET Inspect Ltd | Professional & scientific | 2025 |
| Meta Salon Ltd | Other services | 2023 |
| Metal Solutions (Doncaster) Limited | Water & waste | 2025 |
| Metalliform Engineering Services Limited | | 1944 |
| Metalliform Group Limited | Manufacturing | 2019 |
| Metalliform Holdings Limited | Manufacturing | 2000 |
| Metalliform Products Limited | Professional & scientific | 2004 |
| Metanoia Medical Aesthetics Ltd | Other services | 2022 |
| Metcalf Financial Planning Ltd | Financial services | 2026 |
| Metra Pet Services Limited | Other services | 2024 |
| Metro Garden Buildings Limited | Manufacturing | 1978 |
| Metro Store (Barnsley) Ltd | Wholesale & retail | 2023 |
| Mets Property Services Limited | Real estate | 2023 |
| Mexi Alliance Ltd | Wholesale & retail | 2025 |
| Meyers and Partners Ltd | Administrative & support | 2024 |
| Meynell Holdings Limited | Financial services | 2018 |
| Meynell MIX Limited | Manufacturing | 2014 |
| Meze Turkish Kitchen Ltd | Hospitality | 2024 |
| MFB Beachampton Limited | Construction | 2022 |
| MG Industries Limited | Manufacturing | 2003 |
| MG Network Limited | Professional & scientific | 2023 |
| MG State Cleaning Services Ltd | Administrative & support | 2021 |
| MGC Security Limited | Administrative & support | 2023 |
| Mgcwatches Ltd | Wholesale & retail | 2024 |
| MGI Facility Management Systems Ltd | Professional & scientific | 2017 |
| MH (Barns) Enterprises Limited | Hospitality | 2023 |
| MH Refinishing Ltd | Wholesale & retail | 2020 |
| MHE Services Ltd | Education | 2017 |
| MHF Group Ltd | Real estate | 2025 |
| MHR Drylining Ltd | Construction | 2021 |
| Mia-Grace Boutique Ltd | Wholesale & retail | 2018 |
| Michael David Race Limited | Extraterritorial | 2023 |
| Michael P Jubb & Co Limited | Real estate | 2024 |
| Michal Januszkiewicz Ltd | Transport & logistics | 2017 |
| Mick Gardner Racing Limited | Wholesale & retail | 2004 |
| Mick Jennings Consultancy Services Ltd | Information & communication | 2023 |
| Mickys Brampton Ltd | Hospitality | 2021 |
| Mickys Outlaws CIC | Arts & recreation | 2025 |
| Micromarket Limited | Professional & scientific | 1997 |
| MID Yorkshire Community Foundation C.I.C. | Arts & recreation | 2010 |
| Middlecliffe Club Limited | Hospitality | 2021 |
| Middledata Limited | Professional & scientific | 2024 |
| Middleton Media Group Limited | Professional & scientific | 2020 |
| Middleton Park Square (Leeds) Management Company Limited | Administrative & support | 1997 |
| Middwood Limited | Construction | 2012 |
| Middwood Properties Limited | Real estate | 2022 |
| Mike Walker Golf Limited | Arts & recreation | 2014 |
| Miktol Care Limited | Health & social care | 2025 |
| Mikuta Engineering Ltd | Administrative & support | 2024 |
| Milan AM Limited | Transport & logistics | 2017 |
| Milan Bridal Ltd | Wholesale & retail | 2022 |
| Milcaro Investments Ltd | Administrative & support | 2024 |
| Military Masterpieces Ltd | Manufacturing | 2016 |
| Milk & Honey Eateries Limited | Wholesale & retail | 2023 |
| Mill + Co Properties Limited | Real estate | 2025 |
| Millard Pickering Construction Ltd | Construction | 2020 |
| Millers Concrete & Fencing Supplies Limited | Manufacturing | 2015 |