| Majesty Healthcare Ltd. | Health & social care | 2015 |
| Major Eastwood Limited | Extraterritorial | 2026 |
| Major Projects Travel and Tourism Ltd | Wholesale & retail | 2024 |
| Major Remington Limited | Extraterritorial | 2026 |
| Major Secreg (Publishing) Limited | Information & communication | 2024 |
| Major Toms Social Limited | Hospitality | 2014 |
| Majorelle Interiors Limited | Professional & scientific | 2018 |
| Makayla Ltd | Extraterritorial | 2013 |
| Make & ME Ltd | Manufacturing | 2026 |
| Make a Wish Entertainment Limited | Arts & recreation | 2009 |
| Make Harrogate Ltd | Arts & recreation | 2026 |
| Makers of Progress Ltd | Construction | 2025 |
| Makkawy for Trade Ltd | Wholesale & retail | 2024 |
| Makowhiteness Limited | Professional & scientific | 2007 |
| MAL Signature Services Ltd. | Other services | 2015 |
| Malcolm Rathmell Sport Limited | Wholesale & retail | 2003 |
| Malcolms Tyres & Exhausts Limited | Wholesale & retail | 2006 |
| Malek Contractors Ltd. | Other services | 2000 |
| Mallard Homes Construction Limited | Construction | 2017 |
| Mallard Homes Developments NO 1 Ltd | Construction | 2015 |
| Mallard Homes Ltd | Construction | 2011 |
| Mallard Wealth Ltd | Administrative & support | 2025 |
| Mallartu Limited | Professional & scientific | 2022 |
| Mallow and Marsh Limited | Manufacturing | 2013 |
| Maltby Group Ltd | Construction | 2019 |
| Malvern Inns Ltd | Hospitality | 2010 |
| Malvern Inns Property Ltd | Real estate | 2021 |
| Malvern Inns Three Limited | Hospitality | 2015 |
| Malvern Inns Two Ltd | Hospitality | 2012 |
| Mamma Amelia Ltd | Wholesale & retail | 2022 |
| Mammoth Building and Renovations Limited | Construction | 2022 |
| Mamovements Ltd | Wholesale & retail | 2026 |
| Mamoyo-Elizabeth Limited | Health & social care | 2025 |
| MAN of the Match Limited | Extraterritorial | 2012 |
| Management 47 Limited | Real estate | 2004 |
| Management of Bridgehousegate Limited | Real estate | 1989 |
| Manakeesh House Ltd | Wholesale & retail | 2021 |
| Manchester FM Ltd | Extraterritorial | 2015 |
| Mancunianway Limited | Wholesale & retail | 2011 |
| Mandar Limited | Real estate | 2008 |
| Mane Harrogate Ltd | Other services | 2026 |
| Manhattan Entertainments Limited | Hospitality | 2006 |
| Mannaem EL Gamal Ltd | Wholesale & retail | 2022 |
| Mannion & Co (Helmsley) Limited | Hospitality | 2015 |
| Mannion & Co (York) Limited | Hospitality | 2023 |
| Mannion & Co Easingwold Limited | Real estate | 2022 |
| Mannion & Co Restaurant Group Limited | Hospitality | 2023 |
| Mannix Psychology Limited | Professional & scientific | 2019 |
| Manor Court Management Company (Harrogate) Limited | Real estate | 2000 |
| Manor Farm Dalton Limited | Construction | 2024 |
| Manor Roofing 2 Ltd | Construction | 2026 |
| Manorwest Developments Limited | Administrative & support | 1999 |
| Mansfield Land Company Limited | Real estate | 1991 |
| Manton Photography Limited | | 1986 |
| Manulytica Limited | Manufacturing | 2018 |
| MAP Consult (Yorkshire) Limited | Professional & scientific | 2023 |
| Maple Rubygrace Limited | Financial services | 2024 |
| Maquina Intelligent Networks Limited | Information & communication | 2020 |
| MAR1SA Limited | Extraterritorial | 2026 |
| Marais Capital Ltd | Financial services | 2026 |
| Marban Properties Limited | Real estate | 2025 |
| Marbray Limited | Hospitality | 2008 |
| March TEN Ltd | Information & communication | 2019 |
| Marco a Schrang Garden Design Limited | Administrative & support | 2008 |
| Marcus Bancroft Limited | Extraterritorial | 2026 |
| Marcwood Solutions Ltd | Information & communication | 2026 |
| Mardale Properties Limited | Hospitality | 2019 |
| Mare Nostrum Estates Limited | Professional & scientific | 2019 |
| Mare Nostrum Group Limited | Wholesale & retail | 2003 |
| Mare Nostrum Group Publishing Limited | Wholesale & retail | 2024 |
| Marella Tech Ltd | Information & communication | 2024 |
| Margaret London Limited | Professional & scientific | 2008 |
| Marigold Leisure Limited | Administrative & support | 2021 |
| Mariner Restorations Ltd | Manufacturing | 2024 |
| Mario Bruce Limited | Extraterritorial | 2026 |
| Maritime Progress Limited | Financial services | 2024 |
| Mark Capital Group Holdings Ltd | Financial services | 2026 |
| Mark Harding Ltd | Construction | 2017 |
| Mark Mitchell Ltd | Professional & scientific | 2020 |
| Mark Richards International Consulting Ltd | Professional & scientific | 2018 |
| Marked Perception Limited | Professional & scientific | 2007 |
| Market Demand Limited | Real estate | 1997 |
| Marketcraft Ltd | Professional & scientific | 2024 |
| Marketing Mentors Limited | Professional & scientific | 1994 |
| Marksunny Ltd | Health & social care | 2024 |
| Marlin Environmental Services Limited | Professional & scientific | 2003 |
| Marlin Holdings Limited | Financial services | 2018 |
| Marlyn Metalcraft Limited | Manufacturing | 2006 |
| Marra Scooters Limited | Professional & scientific | 2017 |
| MARRA10 Ltd | Information & communication | 2021 |
| Marriott Joinery Solutions Ltd | Construction | 2025 |
| Marrtree Developments Ltd | Real estate | 1937 |
| Marrtree Investments Limited | Real estate | 2012 |
| Marrtree Limited | Real estate | 1989 |
| Marrtree Residential Ltd | Real estate | 2012 |
| Marsden Homes Limited | Real estate | 2023 |
| Marshall Brothers Finance Co Limited | Real estate | 2013 |
| Marshall Elevators Ltd | Wholesale & retail | 2024 |
| Marshalls Property Development Limited | Real estate | 2006 |
| Marshall’S Vehicle Engineering Ltd | Manufacturing | 2022 |