| Lenvia Collectables Ltd | Wholesale & retail | 2022 |
| LGP Productions Ltd | Administrative & support | 2025 |
| Licky Licky MT Ltd | Transport & logistics | 2025 |
| Lifestyle Rewards Limited | Professional & scientific | 2014 |
| Lime Tree Court Management (Huddersfield) Limited | Households | 2006 |
| Lime Tree Court Residents Management Company Limited | Households | 2012 |
| Lindrick Developments Limited | Real estate | 2012 |
| Liverton Crescent Management Company Limited | Households | 2018 |
| LL Block Construction Ltd | Construction | 2025 |
| Lloyds Quarries Limited | Professional & scientific | 2010 |
| London Security PLC. | Manufacturing | 1897 |
| Longden Durham Ltd | Education | 2024 |
| Longley Hall Developments Ltd | Construction | 2013 |
| Lorna Stewart Hair Limited | Other services | 2006 |
| Love Cleaning (Commercial) Limited | Administrative & support | 2011 |
| LOW Laithes Management Company (Halifax) Limited | Households | 2002 |
| LOW Wood (Horsforth) Management Company Limited | Households | 2019 |
| LS UK Fire Group Ltd | Professional & scientific | 1959 |
| LSS PAY Ltd | Financial services | 2019 |
| Lswp Properties Ltd | Water & waste | 2022 |
| Ltech Lighting Ltd | Wholesale & retail | 2016 |
| Lushy Ltd | Administrative & support | 2024 |
| LWP Site Solutions Ltd | Water & waste | 2020 |
| LY Property Ltd | Real estate | 2014 |
| Lynn Radley Social Care Solutions Ltd | Health & social care | 2022 |
| M and S Service and Repair Ltd | Wholesale & retail | 2016 |
| M B E Property Rentals Limited | Real estate | 2016 |
| M. J. M. (Furnishings) Limited | Administrative & support | 1982 |
| M.A. Trading (UK) Ltd | Manufacturing | 2010 |
| M.A.S. Medical Limited | Health & social care | 2002 |
| M.K Roofing (Yorkshire) Ltd | Construction | 2025 |
| M66 Motors Ltd | Wholesale & retail | 2021 |
| Macmillan Consulting International Ltd | Administrative & support | 2021 |
| MAD About Pizza Ltd | Hospitality | 2022 |
| MAD About Pizzaz Limited | Hospitality | 2025 |
| Madam Yaks Limited | Hospitality | 2016 |
| Madison MAY Consulting Limited | Construction | 2019 |
| Madison MAY Zero Limited | Construction | 2023 |
| Mailygent Ltd | Information & communication | 2026 |
| Mains - Cables - R - US Limited | Wholesale & retail | 2009 |
| Making Bread Limited | Manufacturing | 2019 |
| Malik of Elland Ltd | Real estate | 2026 |
| MAM Stores Limited | Wholesale & retail | 2017 |
| Mamazing Official Ltd | Wholesale & retail | 2024 |
| Manchester City Barbers Ltd | Other services | 2021 |
| Manic Bars Ltd | Hospitality | 2021 |
| Manning Properties (Yorkshire) Limited | Construction | 2019 |
| Manning Property Rentals Limited | Real estate | 2024 |
| Manor Court Yeadon (2) Limited | Real estate | 1987 |
| Maple Court (York) Management Company Limited | Households | 1999 |
| Mares Accounting Limited | Professional & scientific | 2024 |
| Marine Drive Management Company Limited | Real estate | 2024 |
| Marketing Print & Direct Mail Limited | Professional & scientific | 1994 |
| Markham Mount Limited | Households | 2005 |
| Marmerel Limited | Real estate | 2010 |
| Marshalls Building Materials Limited | Professional & scientific | 2002 |
| Marshalls Building Products Limited | Professional & scientific | 1911 |
| Marshalls Concrete Products Limited | Professional & scientific | 2002 |
| Marshalls Directors Limited | Professional & scientific | 2002 |
| Marshalls Dormant NO. 30 Limited | Professional & scientific | 1997 |
| Marshalls Dormant NO.31 Limited | Extraterritorial | 1999 |
| Marshalls Dormant NO.32 Limited | Extraterritorial | 2005 |
| Marshalls EBT Limited | Professional & scientific | 2005 |
| Marshalls Estates Limited | Professional & scientific | 2002 |
| Marshalls Group Limited | Professional & scientific | 1950 |
| Marshalls Landscape Products Limited | Professional & scientific | 2002 |
| Marshalls Mono Limited | Manufacturing | 1952 |
| Marshalls Natural Stone Limited | Professional & scientific | 2002 |
| Marshalls PLC | Professional & scientific | 2004 |
| Marshalls Profit Sharing Scheme Limited | Professional & scientific | 2002 |
| Marshalls Properties Limited | Professional & scientific | 2002 |
| Marshalls Register Limited | Professional & scientific | 2002 |
| Marshalls Stone Products Limited | Professional & scientific | 2002 |
| Marshalls Street Furniture Limited | Professional & scientific | 2003 |
| Matt Squire Masonry Limited | Construction | 2021 |
| Matyasy Productions Ltd | Administrative & support | 2022 |
| MAX Diamonds Limited | Manufacturing | 2019 |
| Maypole View Management Company Ltd | Real estate | 2021 |
| MBE Glazing Limited | Extraterritorial | 2010 |
| MBE Reactive Maintenance Limited | Extraterritorial | 2010 |
| MD Properties Yorkshire Limited | Real estate | 2017 |
| Meadow Court Management Company (Halifax) Limited | Households | 1999 |
| Meadows Window Cleaning Ltd | Administrative & support | 2023 |
| Megane Retail Ltd | Wholesale & retail | 2016 |
| MEL Green Construction Limited | Construction | 1979 |
| Meraki Coffee and Yoga Ltd | Hospitality | 2023 |
| Meran Consulting Ltd | Professional & scientific | 2014 |
| Mereu Ltd | Extraterritorial | 2019 |
| Metcalfe Brickwork Limited | Construction | 2017 |
| Metcalfe Customer Services Ltd | Construction | 2017 |
| Metirium Limited | Construction | 2024 |
| Metro Group Services Limited | Construction | 2006 |
| Mewpsmart Limited | Administrative & support | 2021 |
| MF Composites Ltd | Manufacturing | 2024 |
| MG Cabinworks Limited | Construction | 2012 |
| Michnik IT Solutions Limited | Information & communication | 2005 |
| Microworld (Yorkshire) Limited | Information & communication | 2006 |
| Mike’S Kensington Bar and Rooms Ltd | Hospitality | 2019 |
| Mildec Plant Hire Ltd | Administrative & support | 2020 |
| Millers of Elland Ltd | Hospitality | 2021 |