| Luxury Fibre (Yorkshire) Ltd | Manufacturing | 2021 |
| Luxury Sourcing Ltd | Other services | 2023 |
| Luxus Beds Ltd | Manufacturing | 2024 |
| Luxus Living Ltd | Real estate | 2023 |
| LV Auto's Limited | Wholesale & retail | 2017 |
| LV Holiday Lets Ltd | Hospitality | 2025 |
| LV Property Holding Group Ltd | Real estate | 2025 |
| LW Westgate Limited | Hospitality | 2025 |
| LWM10 Ltd | Financial services | 2006 |
| LWP Trading Ltd | Water & waste | 2025 |
| Lyndonian Limited | Real estate | 1984 |
| Lyntonella Limited | Hospitality | 1999 |
| Lynx Concrete Holdings Limited | Financial services | 2013 |
| Lysjzj Actuarial Limited | Financial services | 2022 |
| Lyth Valley Animal Services Limited | Agriculture & fishing | 2024 |
| M & a Properties (West Yorkshire) Ltd | Real estate | 2017 |
| M & C Global LP | | 2009 |
| M & G Investments Ltd | Construction | 2011 |
| M & M Oral Healthcare Limited | Health & social care | 2011 |
| M & T Landscaping Limited | Administrative & support | 2015 |
| M a W Electrical Services Ltd | Construction | 2007 |
| M and P Housing Ltd | Households | 2025 |
| M and G Flooring Consultants Limited | Construction | 2014 |
| M Brake Contracting Limited | Administrative & support | 2018 |
| M CAD Ltd | Construction | 1997 |
| M D G Properties Ltd | Real estate | 2006 |
| M H & J Cooper Limited | Real estate | 2015 |
| M H ALI Consultancy Limited | Administrative & support | 2019 |
| M H Medics Limited | Health & social care | 2016 |
| M H Property Management Limited | Real estate | 2022 |
| M H Repair Services Ltd | Wholesale & retail | 2021 |
| M J R Holmfirth Limited | Real estate | 2021 |
| M J Shirty Developments Ltd | Real estate | 2015 |
| M M Enterprises (Yorkshire) Ltd | Hospitality | 2018 |
| M Mallinder Building &Joinery Ltd | Construction | 2022 |
| M Potts Tree Services Limited | Agriculture & fishing | 2015 |
| M R Properties & Developments Limited | Real estate | 2026 |
| M S J Laser Engraving Ltd | Wholesale & retail | 2026 |
| M S S Education Limited | Other services | 2022 |
| M Tunkara Ltd | Transport & logistics | 2025 |
| M&A Sheff Limited | Wholesale & retail | 2026 |
| M&A Travel Ltd | Administrative & support | 2019 |
| M&Co Lighting Ltd | Construction | 2023 |
| M&E Housing Ltd | Real estate | 2026 |
| M&H Designs Ltd | Wholesale & retail | 2014 |
| M&J Auto Services Ltd | Wholesale & retail | 2021 |
| M&K Logistics Limited | Transport & logistics | 2019 |
| M&K Willings LLP | | 2012 |
| M&M Associates Leeds Limited | Wholesale & retail | 2025 |
| M&M Catering (Liverpool) Ltd | Administrative & support | 2017 |
| M&M Worldwide Limited | Construction | 2016 |
| M&S Properties Yorkshire Limited | Real estate | 2020 |
| M&S Tiling Limited | Construction | 2023 |
| M-Pax Limited | Administrative & support | 2022 |
| M. Womack Limited | Administrative & support | 1965 |
| M.A.S. Shop Fitters Limited | Construction | 2004 |
| M.B. & S.P. Ascough Limited | Construction | 2019 |
| M.B.M Electrics Ltd | Construction | 2010 |
| M.C.S Contracting Limited | Construction | 2014 |
| M.E Autos Car and Light Commercial Ltd | Wholesale & retail | 2006 |
| M.G. Flooring Limited | Construction | 2009 |
| M.K. Developments Yorkshire Limited | Hospitality | 2024 |
| M.M Landscapes & Building Limited | Administrative & support | 2022 |
| M.T.F Management Limited | Real estate | 2002 |
| M.Touray Limited | Financial services | 2019 |
| M1 Fencing & Decking Ltd | Construction | 2023 |
| M1 Interior Systems Ltd | Construction | 2019 |
| M1 Nails & Beauty Limited | Other services | 2024 |
| M2R Education Limited | Administrative & support | 2013 |
| M2R Global Limited | Administrative & support | 2012 |
| M2R Limited | Administrative & support | 2001 |
| M7 Heating & Plumbing Ltd | Construction | 2025 |
| MA Landscapes Limited | Administrative & support | 2006 |
| MA Vehicles Limited | Wholesale & retail | 2014 |
| Macgregor Black Limited | Administrative & support | 2017 |
| Machine Mate Plant & Tool Hire Ltd | Transport & logistics | 2026 |
| Machinesdirect (UK) Limited | Wholesale & retail | 2005 |
| Machtech (Wakefield) Limited | Administrative & support | 2006 |
| Machtech Technology Limited | Manufacturing | 2009 |
| Machto CIC | Other services | 2024 |
| Maciej Olczak Ltd | Wholesale & retail | 2019 |
| Macro Science Ltd | Information & communication | 2022 |
| Macwan Properties Ltd | Real estate | 2024 |
| MAD and BAD Ltd | Wholesale & retail | 2017 |
| MAD Ducks Media Ltd | Information & communication | 2019 |
| MAD Patches Ltd | Wholesale & retail | 2017 |
| Made by Bramble Limited | Information & communication | 2024 |
| Made Morpeth Ltd | Other services | 2021 |
| Made With Love by Sophie Limited | Manufacturing | 2017 |
| MADE2MOVE Together CIC | Education | 2026 |
| Madelaine Maria Transport Ltd | Transport & logistics | 2026 |
| Maderatimber Ltd | Wholesale & retail | 2025 |
| Madina Masjid Ltd | Other services | 2013 |
| Madre Developments Ltd | Construction | 2024 |
| Mafuzho Ltd | Health & social care | 2026 |
| Maggies Halifax Ltd | Hospitality | 2015 |
| Magnetic Holdings Yorkshire Ltd | Households | 2025 |
| Magnum Venture Investments Limited | Administrative & support | 2008 |
| Mahapatra Associates Ltd | Professional & scientific | 2019 |
| Mahazia Invest Ltd. | Professional & scientific | 2016 |