| Lwrcyber Ltd | Information & communication | 2024 |
| Lynx Fabrics Limited | Wholesale & retail | 1978 |
| M & L Fleet Services Ltd | Wholesale & retail | 2024 |
| M & L Siddle Limited | Wholesale & retail | 2005 |
| M & M Joinery & Roofing Limited | Construction | 2019 |
| M & M Office Services Limited | Professional & scientific | 2017 |
| M & S Fitters Ltd | Other services | 2022 |
| M 1 CRE Limited | Health & social care | 2022 |
| M and B Barker Holdings Limited | Professional & scientific | 2000 |
| M and E Foods Limited | Hospitality | 2014 |
| M C W Limited | Mining & quarrying | 2002 |
| M F C GAS and Heating Engineer Ltd | Construction | 2017 |
| M Horton Joinery & Fencing Limited | Manufacturing | 2018 |
| M N Stores Ltd | Wholesale & retail | 2016 |
| M S Connections Limited | Construction | 2005 |
| M S Event Management Limited | Arts & recreation | 2023 |
| M S Eyewear UK Limited | Wholesale & retail | 2008 |
| M S K Hire Limited | Administrative & support | 2015 |
| M&A Asset Management Ltd | Real estate | 2024 |
| M&J Framing Ltd | Wholesale & retail | 2014 |
| M&M Building and Roofing Ltd | Construction | 2019 |
| M. & B. Transport Services Limited | Professional & scientific | 1973 |
| M. and B. Barker Limited | Real estate | 1966 |
| M. Begum Ltd | Health & social care | 2026 |
| M. Haleem Limited | Health & social care | 2006 |
| M.D. Construction (Bolton) Limited | Construction | 1998 |
| M.D. Jones Roofing & Building Ltd. | Construction | 2019 |
| M.Moore Properties Limited | Construction | 1987 |
| M.S.Halal Meats Limited | Wholesale & retail | 2010 |
| MA Nasir Ltd | Wholesale & retail | 2024 |
| MA PPM Consulting Ltd | Information & communication | 2020 |
| MA Services (Yorkshire) Limited | Other services | 2016 |
| Maaf Foods Ltd | Hospitality | 2023 |
| MAC Air Conditioning and Installation Limited | Construction | 2025 |
| MAC Properties North West Ltd | Real estate | 2023 |
| Macaulay & Co Ltd | Real estate | 2024 |
| Machine Control Design Limited | Professional & scientific | 2019 |
| Machine Shop Special Projects Limited | Arts & recreation | 2001 |
| Macmarr Pubs Ltd | Hospitality | 2021 |
| Madassery Healthcare Limited | Health & social care | 2017 |
| Made Events Solutions Ltd | Administrative & support | 2014 |
| Madina Food NE Ltd | Wholesale & retail | 2025 |
| MAGS4 Limited | Information & communication | 2024 |
| Mahico Limited | Hospitality | 2017 |
| Mahnoor Enterprises Ltd | Wholesale & retail | 2026 |
| Mahroof Audiological Services Limited | Health & social care | 2014 |
| Mahroof Clinical Management Ltd | Extraterritorial | 2021 |
| Maiden Cricket Clothing Limited | Wholesale & retail | 2022 |
| Mainhair Ltd | Wholesale & retail | 2025 |
| Maison DE Clumber Limited | Wholesale & retail | 2018 |
| Maison Vante Ltd | Wholesale & retail | 2026 |
| Majeed Property Associates Ltd | Real estate | 2024 |
| Maketattoo Ltd | Other services | 2019 |
| Makkah Foodstore KLY Ltd | Wholesale & retail | 2022 |
| Malcolm Barker Poultry Specialists Limited | Construction | 1985 |
| Malevi Group Ltd | Financial services | 2026 |
| Malham's Sleeping Giant Limited | Hospitality | 2015 |
| Mali Boxing Ltd | Arts & recreation | 2019 |
| Malsis Properties Ltd | Hospitality | 2025 |
| Malsis Travel Ltd | Transport & logistics | 2025 |
| Maltby’S Food Ltd | Hospitality | 2025 |
| MAN With Van Long Wheelbase Ltd | Transport & logistics | 2026 |
| Manchester and Company Limited | Professional & scientific | 2013 |
| Mandstrad Ltd | Information & communication | 1999 |
| Mango Training Ltd | Other services | 2020 |
| Manor Blinds Ltd | Construction | 2020 |
| Manor Drive (Keighley) Limited | Households | 2018 |
| Manor Park Healthcare Ltd | Health & social care | 2025 |
| Manor Park Lifts Limited | Manufacturing | 2013 |
| Manson Construction Limited | Construction | 2014 |
| Many Hands 25 C.I.C. | Wholesale & retail | 2017 |
| MAP Solutions Limited | Construction | 2025 |
| Maple Management Systems Ltd | Professional & scientific | 2022 |
| Maple Origin Ltd | Transport & logistics | 2025 |
| Maple Pilates Limited | Arts & recreation | 2026 |
| Maplle Corp Limited | Financial services | 2010 |
| Marcon Homes Ltd. | Real estate | 2006 |
| Marcos Jewellery Limited | Wholesale & retail | 2024 |
| Marino Homes Ltd | Real estate | 2025 |
| Marionette Studios Ltd | Information & communication | 2011 |
| Maris Media Limited | Arts & recreation | 2019 |
| Mark Finn Laboratory Furniture Limited | Construction | 2018 |
| Mark Gilbert Construction Ltd | Construction | 2015 |
| Mark Hull Carpets Limited | Construction | 2003 |
| Mark Mccallion Ltd | Construction | 2015 |
| Mark Startin Solutions Limited | Professional & scientific | 2016 |
| Mark Stevens Music Ltd | Information & communication | 2011 |
| Mark Symes Communications Ltd | Energy | 2013 |
| Mark Taylor Trees and Landscaping Limited | Other services | 2025 |
| Mark Wheeler Retail Services Ltd | Professional & scientific | 2020 |
| Market Cafe Keighley Limited | Wholesale & retail | 2012 |
| Market Pantry Keighley Limited | Wholesale & retail | 2017 |
| Marlin Windows (Yorkshire) Limited | Extraterritorial | 2025 |
| Marlin Windows Limited | Manufacturing | 2008 |
| Marsden Park (MGT) Ltd | Real estate | 2015 |
| Marshall Davies Ltd | Administrative & support | 2026 |
| Marshall Electrical Services (Yorkshire) Ltd | Construction | 2019 |
| Marshall Krysko Limited | Professional & scientific | 2018 |
| Marshgrove Financial Ltd | Financial services | 2017 |
| Martial Mastery Limited | Wholesale & retail | 2019 |