| Luxurova Aesthetic Limited | Other services | 2022 |
| Luxury Bespoke Ltd | Wholesale & retail | 2020 |
| Luxury Properties Specialist Ltd | Real estate | 2026 |
| LVK Properties Limited | Wholesale & retail | 1920 |
| LYX Logistics Ltd | Transport & logistics | 2020 |
| M & J Crawshaw Limited | Administrative & support | 2026 |
| M & J Estates Ltd | Real estate | 2016 |
| M & J Geraghty Limited | Construction | 2001 |
| M & M Auto Salvage Limited | Extraterritorial | 2009 |
| M & N Bottomley Ltd | Construction | 2015 |
| M & S Nurseries Ltd | Education | 2010 |
| M & S Process Engineers Ltd. | Professional & scientific | 1995 |
| M a Fradgley HGV & Trailer Repairs Ltd | Administrative & support | 2012 |
| M a H Expediting and Inspection Services Limited | Professional & scientific | 2014 |
| M a Jagger Limited | Real estate | 1999 |
| M a Property Estates Limited | Real estate | 2023 |
| M and D Poultry Limited | Agriculture & fishing | 2013 |
| M B Vehicle Service & Repairs Ltd | Wholesale & retail | 2025 |
| M Burrows Furniture World Limited | Wholesale & retail | 2004 |
| M Challenger Transport Limited | Transport & logistics | 2015 |
| M D (Northern) Trading Ltd | Wholesale & retail | 2020 |
| M G Hoggett Limited | Professional & scientific | 2018 |
| M H Builders & Sons Ltd | Construction | 2023 |
| M H Holdings & Sons Ltd | Real estate | 2025 |
| M H North Holdings Ltd | Construction | 2025 |
| M Hussain Limited | Real estate | 2008 |
| M Ihsan Limited | Professional & scientific | 2005 |
| M J Drake Recovery Ltd | Transport & logistics | 2026 |
| M L Breen Limited | Manufacturing | 2016 |
| M L Yorkshire Properties Limited | Households | 2022 |
| M Little Contractors Ltd | Construction | 2023 |
| M M Education Limited | Education | 2000 |
| M P Calcott Limited | Construction | 2020 |
| M R Surveying and Fire Safety Ltd | Other services | 2017 |
| M S a Engineering Systems Limited | Manufacturing | 1991 |
| M S Lally Holdings Ltd | Financial services | 2025 |
| M Town Ltd | Construction | 2010 |
| M Tuck Brickworks Limited | Construction | 2015 |
| M Tufayl Limited | Administrative & support | 2014 |
| M Whittel Joiners and Builders Limited | Construction | 2021 |
| M&A Havekin Ltd | Information & communication | 2006 |
| M&J Goodman Ltd | Professional & scientific | 2020 |
| M&J Performance Ltd | Wholesale & retail | 2022 |
| M&J Swift Ltd | Transport & logistics | 2021 |
| M&M Courier Ltd | Transport & logistics | 2026 |
| M&M Fitness Limited | Health & social care | 2025 |
| M&M Vision Ltd | Wholesale & retail | 2019 |
| M&N Car Body Repair Limited | Wholesale & retail | 2021 |
| M&S Consultancy Ltd | Information & communication | 2025 |
| M. Womersleys Ltd | Construction | 2020 |
| M.A. Estates Limited | Real estate | 1998 |
| M.HPALLETS247 Ltd | Wholesale & retail | 2025 |
| M.J.Martin Electrical Ltd | Construction | 2022 |
| M.K. Consultants (U.K.) Limited | Manufacturing | 2013 |
| M.S. Design International Limited | Real estate | 1981 |
| M.V. Consulting (Brighouse) Limited | Financial services | 2015 |
| M2 Plastering & Drylining Ltd | Construction | 2018 |
| M3 Limited | Health & social care | 2024 |
| M8CHECK Ltd | Information & communication | 2026 |
| MA Business and Financial Management for Schools Limited | Professional & scientific | 2007 |
| MA Autocare Ltd | Wholesale & retail | 2024 |
| MA Health Ltd | Health & social care | 2010 |
| MA Legal Services Ltd | Professional & scientific | 2017 |
| Maaf Halifax Limited | Hospitality | 2024 |
| Maas Pumps (UK) Limited | Extraterritorial | 2021 |
| Mackereth Opticians Limited | Wholesale & retail | 2011 |
| Macmillan Belliss Consulting Limited | Professional & scientific | 2011 |
| Macoy Properties Ltd | Real estate | 2026 |
| MAD About Bubbly Limited | Administrative & support | 2009 |
| MAD Duck Ltd | Wholesale & retail | 2012 |
| Madani Pharmaceuticals Ltd | Health & social care | 2022 |
| Made by Compound Ltd | Information & communication | 2025 |
| Madeira Holdings Limited | Households | 2009 |
| Madidox Limited | Wholesale & retail | 2025 |
| Madina Associates Ltd | Education | 2012 |
| Mads Curry Company Ltd | Hospitality | 2025 |
| MAG Fabrications Limited | Manufacturing | 2014 |
| Magic Bazaar Ltd | Wholesale & retail | 2026 |
| Magic Bean Properties Ltd | Real estate | 2022 |
| Magic Bean Residential Ltd | Households | 2023 |
| Magic Cafe Limited | Hospitality | 2019 |
| Magic Carpets (Yorkshire) Ltd | Wholesale & retail | 2023 |
| Magical Potions Ltd | Health & social care | 2016 |
| Magnetic Analysis Limited | Professional & scientific | 1973 |
| Magnus Healthcare ZS Ltd | Administrative & support | 2022 |
| Magpro International Ltd | Construction | 2022 |
| Mags on Ramps C.I.C. | Arts & recreation | 2012 |
| Maguire & Co Joinery Ltd | Manufacturing | 2025 |
| Mahboob Contracting Group Limited | Administrative & support | 2015 |
| Mahmood Properties (Halifax) Ltd | Real estate | 2023 |
| Mahmood Solutions Ltd | Transport & logistics | 2026 |
| Maid IT Clean Ltd | Administrative & support | 2024 |
| Maifair Ltd | Wholesale & retail | 2024 |
| Mailroom Equipment Limited | Wholesale & retail | 2010 |
| Maismetcalfe Ltd | Other services | 2024 |
| Majestic Property Partners Ltd | Households | 2023 |
| Make Room Holdings Ltd | Professional & scientific | 2019 |
| Make Room Outside Ltd | Construction | 2020 |
| Make Room Projects Ltd | Construction | 2025 |
| Make Soluble Limited | Manufacturing | 2019 |