| Mdst Property Ltd | Real estate | 2019 |
| ME Time Therapy Ltd | Health & social care | 2020 |
| Meadrate Limited | Wholesale & retail | 2019 |
| Meatailer Limited | Hospitality | 2011 |
| Media Branding Ltd | Arts & recreation | 2015 |
| Medical Briefing Limited | Health & social care | 1984 |
| Mediterranean Cuisine Limited | Hospitality | 2023 |
| Medpharm Ventures Ltd | Wholesale & retail | 2012 |
| Medusa Stoves Limited | Wholesale & retail | 2014 |
| Mehwish Amin Ltd | Health & social care | 2023 |
| MEK Summat C.I.C. | Arts & recreation | 2026 |
| Meridale Investments Limited | Real estate | 2002 |
| Meronway Limited | Real estate | 2008 |
| Met-Guard Automation Ltd | Manufacturing | 2021 |
| MHA Architecture Limited | Professional & scientific | 2019 |
| Mhai Thai Wellness Ltd | Other services | 2026 |
| MHFA-T4L Limited | Education | 2018 |
| MHS Cleaning Group Limited | Administrative & support | 2026 |
| MI Business Change Consultancy Ltd | Professional & scientific | 2016 |
| Miaboo Limited | Manufacturing | 2016 |
| Michael Holmes Partnership Limited | Professional & scientific | 1997 |
| Micklethwaite Cottages Limited | Real estate | 2025 |
| Mico's Cleaning Services Limited | Administrative & support | 2022 |
| Mikaesa Limited | Administrative & support | 2017 |
| Mike Bradley Safety Netting Limited | Construction | 2015 |
| Miller Investments (Services) | Financial services | 2013 |
| Mini Maison Saltaire Ltd | Administrative & support | 2026 |
| Mink Properties Limited | Real estate | 2008 |
| Mirror Blind Records Limited | Information & communication | 2025 |
| Mirror Mirror Baildon Limited | Other services | 2018 |
| Miss Laura Carter Limited | Other services | 2020 |
| Mission Impact Ltd | Administrative & support | 2025 |
| Mitchell Secure Technologies Limited | Administrative & support | 2023 |
| MJ Logistics (Yorkshire) Limited | Other services | 2025 |
| MJ Thornton Consultancy Ltd | Professional & scientific | 2022 |
| MJM Renovations Ltd | Construction | 2018 |
| MJS Installation Services Ltd | Manufacturing | 2020 |
| MJS Properties Yorkshire Ltd | Real estate | 2025 |
| MK of Keighley Limited | Hospitality | 2016 |
| MK Osteopath & Associates Limited | Health & social care | 2017 |
| MKZ Group Ltd | Wholesale & retail | 2025 |
| MM Pharma Consultants Ltd | Professional & scientific | 2025 |
| MMA Healthcare Holdings Ltd | Financial services | 2024 |
| MMA Healthcare Locums Ltd | Health & social care | 2024 |
| MMA Healthcare Services Limited | Hospitality | 2017 |
| MN Carpentry Limited | Construction | 2014 |
| Mnnh Consulting Ltd | Information & communication | 2023 |
| Mobility Bathroom Installations Ltd | Construction | 2023 |
| Mobility Group Holdings Ltd | Financial services | 2023 |
| Modulux Limited | Wholesale & retail | 2024 |
| Mofo Body Mechanics Ltd | Health & social care | 2018 |
| Mojojack Music Ltd | Health & social care | 2022 |
| Monetized Debt Solutions Ltd | Real estate | 2019 |
| Moneymindmuscle Ltd | Other services | 2025 |
| Moor Computing Ltd | Information & communication | 2025 |
| Moor Education Limited | Education | 2023 |
| Mooredge Gardens Ltd | Administrative & support | 2021 |
| Moorfield Estates Limited | Financial services | 2022 |
| Moorings HR Limited | Administrative & support | 2025 |
| Moot Marvin Estate Agent Ltd | Manufacturing | 2024 |
| More and Sure Limited | Wholesale & retail | 2025 |
| Mortgage and Protection Surgery Limited | Financial services | 2015 |
| Mortgage Bees Limited | Financial services | 2018 |
| Mortgage Save 2000 Limited | Financial services | 2001 |
| Mortgage Surgery Limited | Financial services | 2023 |
| Moss and Moon Ltd | Wholesale & retail | 2026 |
| Mother Shipton's (Knaresborough) Limited | Hospitality | 2025 |
| Motor Dealers United (UK) CIC | Other services | 2025 |
| MP Automotive Parts UK Ltd | Wholesale & retail | 2020 |
| Mpharm Padel Limited | Arts & recreation | 2026 |
| Mpharm Properties Limited | Real estate | 2024 |
| Mpxi UK Limited | Professional & scientific | 2019 |
| MRT Chemicals Limited | Professional & scientific | 2011 |
| MSJ Wholesale Ltd | Wholesale & retail | 2022 |
| MSM Construction (Northern) Ltd. | Construction | 2005 |
| Msptl Positive Ltd | Education | 2022 |
| MT Surveys Ltd | Professional & scientific | 2012 |
| Mtkhan Ltd | Other services | 2025 |
| MTL Installations Limited | Manufacturing | 2013 |
| MUH Investments Limited | Real estate | 2021 |
| Muji Rashid Ltd | Information & communication | 2025 |
| Muljay Limited | Other services | 2023 |
| Munawar Consultancy Ltd | Professional & scientific | 2017 |
| Munchi Shipley Ltd | Hospitality | 2025 |
| Muscle Motors Limited | Wholesale & retail | 2021 |
| Music Box - Inspiring Voices CIC | Education | 2023 |
| Muslim Women's Council | Other services | 2011 |
| Mutar Ventures Ltd | Real estate | 2024 |
| MW Hospitality Ltd | Hospitality | 2025 |
| My DIY Wardrobes Limited | Manufacturing | 2026 |
| My Dogs Stuff Ltd | Wholesale & retail | 2021 |
| My Home Ventilation Ltd | Construction | 2018 |
| My Life Coach Limited | Professional & scientific | 2009 |
| My Little Farm Spa Limited | Other services | 2015 |
| My Transitions Ltd | Public administration | 2020 |
| Mymup Digital Ltd | Information & communication | 2018 |
| Myra Trading Limited | Wholesale & retail | 2018 |
| N.B.D.S. Transport Limited | Professional & scientific | 2012 |
| Nabwood Convenience Store Ltd | Wholesale & retail | 2026 |
| Nail Central Limited | Other services | 2026 |