| Lord & Gray Limited | Wholesale & retail | 2022 |
| Love Brownies Together Ltd | Manufacturing | 2020 |
| Love, Roya Ltd | Wholesale & retail | 2025 |
| LOW Acre Apartments Management Company Ltd | Real estate | 2023 |
| Lower Gill Holidays Limited | Hospitality | 2002 |
| Lower Paradise Farm Ltd | Agriculture & fishing | 2018 |
| Luda Ventures Limited | Real estate | 2025 |
| Lunara Group Limited | Administrative & support | 2025 |
| Luxury Country Apartments Ltd | Real estate | 2025 |
| LWC (Luxury Watches) Ltd | Wholesale & retail | 2016 |
| LWC (Luxury Watches) Services Limited | Other services | 2024 |
| Lyndale Property Limited | Real estate | 2026 |
| M & F Developments (2025) Limited | Construction | 2017 |
| M & F Holdings (2025) Limited | Real estate | 2017 |
| M & H Developments Lancashire Ltd | Construction | 2019 |
| M Andrews (Electrical) Ltd. | Construction | 2002 |
| M B Plant Hire Limited | Construction | 2002 |
| M Beech Engineering Ltd | Construction | 2008 |
| M G R Hotels Limited | Hospitality | 2005 |
| M J Drake Plumbing & Heating Ltd | Construction | 2013 |
| M Kirk Ltd | Wholesale & retail | 2003 |
| M Knights Driver Hire & Training Limited | Transport & logistics | 2025 |
| M L Support Services Limited | Administrative & support | 2024 |
| M LEE Design Limited | Construction | 2017 |
| M S Holmes Electrical Contractors Limited | Construction | 2003 |
| M T J Booth Limited | Health & social care | 2012 |
| M&C Home Furnishings Ltd | Wholesale & retail | 2024 |
| Maah Developments Ltd | Real estate | 2022 |
| Macbeth Hotels Ltd | Hospitality | 2014 |
| Macden Beauty Ltd | Wholesale & retail | 2018 |
| Macvean Hair Limited | Other services | 2025 |
| Macvean Properties Limited | Real estate | 2002 |
| Made to Measure Wooden Gates Ltd | Extraterritorial | 2023 |
| Mahina Studios Limited | Other services | 2025 |
| Mahmooda Naeem Medics Ltd | Health & social care | 2013 |
| Mahoney Construction Limited | Construction | 2019 |
| Malada Ltd | Wholesale & retail | 2021 |
| Malcolm Baines Electrical Ltd | Construction | 2017 |
| Malham Climate Resilience Services Ltd | Professional & scientific | 2021 |
| Malham Leisure Limited | Real estate | 2014 |
| Malham Ltd | Administrative & support | 2016 |
| Malhamdale Glamping Limited | Hospitality | 2025 |
| Malhamdale Holidays Limited | Hospitality | 2003 |
| Malhamdale.Com Limited | Information & communication | 2003 |
| Malinois Equipment Ltd | Manufacturing | 2023 |
| Manflu Limited | Wholesale & retail | 2003 |
| Mangia Bites Limited | Hospitality | 2024 |
| Manifest Marketing Limited | Professional & scientific | 2002 |
| Manta Tatton Limited | Information & communication | 2025 |
| Marek Aurelius Cycles Limited | Manufacturing | 2012 |
| Marily London Ltd | Professional & scientific | 2018 |
| Mark Telford Construction Limited | Construction | 2002 |
| Marlow House Residents' Association (Morecambe) Limited | Households | 1994 |
| Marsden a E S Limited | Administrative & support | 2008 |
| Marsden Contract Services Limited | Administrative & support | 2017 |
| Marsden Holdings Ltd | Administrative & support | 2017 |
| Marshall and Stocker Limited | Health & social care | 2010 |
| Marshall Taylor Properties Ltd | Real estate | 2011 |
| Marshalls Transport Ltd | Transport & logistics | 2016 |
| Martin Hayes Consulting Limited | Administrative & support | 2025 |
| Martyn Woolley Design Limited | Professional & scientific | 2021 |
| Mary Cartlidge ISW Limited | Health & social care | 2023 |
| Masons Heritage Holdings Ltd | Real estate | 2023 |
| Masons Textiles Holdings Limited | Financial services | 2024 |
| Masons Textiles Limited | Manufacturing | 1993 |
| Masons Textiles Property Limited | Financial services | 2024 |
| Mast Court Investment Limited | Extraterritorial | 2017 |
| Mastabs Restaurant Ltd | Hospitality | 2024 |
| Matem Retail Ltd | Wholesale & retail | 2024 |
| Matias Security Limited | Professional & scientific | 2011 |
| Matt Baines Electrical Ltd | Manufacturing | 2018 |
| Matthew Gore (UK) Limited | Extraterritorial | 2015 |
| Maudsley Agricultural Construction Ltd | Construction | 2024 |
| Maxfields Ltd | Construction | 2003 |
| Mayil Info Systems Limited | Information & communication | 2022 |
| Maypole Long Preston Ltd | Hospitality | 2022 |
| MBF Biomass Limited | Professional & scientific | 2016 |
| MC Sports (Skipton) Ltd | Wholesale & retail | 2013 |
| Mcdowell Westlake Limited | Professional & scientific | 2012 |
| Mclenna Limited | Professional & scientific | 2017 |
| Mcnally Electrical (Yorkshire) Limited | Manufacturing | 2015 |
| Mcnally Renewables Limited | Construction | 2021 |
| MDC Building Contractors Ltd | Construction | 2022 |
| MDC Learning Limited | Education | 2017 |
| MDP Project Solutions Ltd. | Professional & scientific | 2011 |
| MDS Haulage Services Ltd | Transport & logistics | 2025 |
| Mech Tech Industries Limited | Manufacturing | 1989 |
| Meeson Times Limited | Real estate | 2013 |
| Meesons a. I. Limited | Construction | 1982 |
| Meesons Futures Limited | Extraterritorial | 2014 |
| Meesons Holdings Limited | Professional & scientific | 1994 |
| Meiji Limited | Professional & scientific | 2025 |
| Mercian Machine Tool Solutions Ltd | Professional & scientific | 2022 |
| Mercurai Ltd | Wholesale & retail | 2011 |
| Mere Mortal Firewall Limited | Information & communication | 2022 |
| Merritt & Fryers Limited | Manufacturing | 1935 |
| Metcalfe Driver Training Limited | Education | 2016 |
| Mewies Solicitors Limited | Professional & scientific | 2016 |
| MG Holidays Ltd | Administrative & support | 2023 |
| Mhriw Holdings Limited | Financial services | 2025 |