| Mallard Consultancy Ltd | Professional & scientific | 1997 |
| Mallard Consulting Ltd | Professional & scientific | 2019 |
| Mallard Couriers Ltd | Transport & logistics | 2025 |
| Mallian Limited | Professional & scientific | 2022 |
| Malling AXE Homes Ltd | Real estate | 2017 |
| Mallotus Investments Limited | Professional & scientific | 2002 |
| Maloney Training and Education Limited | Education | 2017 |
| Malta Negoce Holding Limited | Financial services | 2016 |
| Malthouse (Doncaster) Management Company Ltd | Real estate | 2022 |
| Maltings (Doncaster) Management Company Ltd | Real estate | 2011 |
| Maltings Holdings Limited | Professional & scientific | 2015 |
| Maltings OFF Road Limited | Wholesale & retail | 2008 |
| Malton Properties Limited | Hospitality | 2004 |
| Maluma Global Transport Ltd | Transport & logistics | 2023 |
| Mamas Kitchen Ltd | Hospitality | 2025 |
| Mambo Jambo Ltd | Hospitality | 1997 |
| Mamy-Hayde Limited | Hospitality | 2013 |
| MAN WAH Takeaway Limited | Hospitality | 2026 |
| Mana Homes Ltd | Construction | 2017 |
| Managebyapps Ltd | Other services | 2011 |
| Managed Support Recruitment Ltd | Administrative & support | 2019 |
| Manakey EU Ltd | Other services | 2024 |
| Manakin Ltd | Arts & recreation | 2021 |
| Mancebo Consultancy Ltd | Professional & scientific | 2024 |
| Mandark Ltd | Information & communication | 2018 |
| Mandora Haulage Ltd | Transport & logistics | 2020 |
| Manety Limited | Professional & scientific | 2023 |
| Manifest Events Ltd | Extraterritorial | 2024 |
| Manissan Ltd | Health & social care | 2015 |
| Mann Made Properties Ltd | Construction | 2018 |
| Mann Property Management Limited | Households | 2022 |
| Mannah's Retails Ltd | Wholesale & retail | 2025 |
| Manntra Homes Limited | Construction | 2022 |
| Mano Logistics Limited | Transport & logistics | 2019 |
| Manor Civils & Groundworks Ltd | Construction | 2019 |
| Manor Construction (South Yorkshire) Limited | Construction | 2006 |
| Manor Developments (Belton) Ltd | Construction | 2018 |
| Manor Farm Marr Developments Ltd | Administrative & support | 2015 |
| Manor Parker Grove Limited | Information & communication | 2026 |
| Manor Property and Garden Services Limited | Real estate | 2011 |
| Manor Tyres Limited | Wholesale & retail | 2005 |
| Manorom Ltd | Other services | 2026 |
| Mansfield Healthcare Limited | Wholesale & retail | 2023 |
| Mansfield Town FC Academy Ltd | Education | 2011 |
| Mansion Slow Limited | Real estate | 2024 |
| Mansory Maintenance Ltd | Public administration | 2024 |
| Mantal Deli Ltd | Hospitality | 2025 |
| Manual Focus Ltd | Information & communication | 2025 |
| Manuola Ltd | Real estate | 2025 |
| MAP Contracting Ltd | Professional & scientific | 2025 |
| MAP Tech Limited | Professional & scientific | 2025 |
| Mapibo Ltd | Wholesale & retail | 2022 |
| Maple & Moor Ltd | Extraterritorial | 2026 |
| Maple Lettings and Property Management Limited | Real estate | 2014 |
| Maplewell Digital Ltd | Extraterritorial | 2026 |
| Mappin Grange Care Ltd | Extraterritorial | 2021 |
| Mapps International Couriers Ltd | Transport & logistics | 2025 |
| Mara Tudorache Ltd | Professional & scientific | 2019 |
| Marael Group Limited | Hospitality | 2026 |
| Marambe Properties Ltd | Real estate | 2025 |
| Maranellos(Yorkshire) Limited | Hospitality | 2025 |
| Marantos Pizza Limited | Hospitality | 2025 |
| Marbil IT Community Interest Company | Information & communication | 2007 |
| Marble & Meadow Trading Ltd | Extraterritorial | 2026 |
| Marble Mango Holdings Ltd | Extraterritorial | 2026 |
| Marble Square Management Company Limited | Real estate | 2022 |
| Marblechip Limited | Real estate | 2005 |
| Marblegate Capital Services Ltd | Information & communication | 2025 |
| Marc-Invest Ltd. | Other services | 2014 |
| Marcelo Pizza Ltd | Hospitality | 2026 |
| March Haus Ltd | Information & communication | 2026 |
| Marchet E-Commerce Ltd | Wholesale & retail | 2022 |
| Marchet Markets Ltd | Wholesale & retail | 2025 |
| Marchini Ltd | Professional & scientific | 2026 |
| Marchlinska LLP | | 2015 |
| Marco Holding Limited | Financial services | 2021 |
| Marcrist Holdings Limited | Manufacturing | 1982 |
| Marcrist International Limited | Manufacturing | 1999 |
| Marcus Coates Studio Ltd | Arts & recreation | 2023 |
| Marek Tech Services Limited | Other services | 2025 |
| Marex Holdings Limited | Extraterritorial | 2017 |
| Marflex Ltd | Transport & logistics | 2019 |
| Margaret Rose House Limited | Extraterritorial | 2012 |
| Marian Comnea Ltd | Education | 2025 |
| Marian's Removal's Ltd | Transport & logistics | 2025 |
| Marian.B Ltd | Transport & logistics | 2025 |
| MARIANPOPA92 Ltd | Transport & logistics | 2018 |
| Maridian Limited | Real estate | 2019 |
| Marily Ltd | Transport & logistics | 2021 |
| Marine Lake Hotel Ltd | Hospitality | 2025 |
| Marine Lake Spa & Apartments Ltd | Hospitality | 2025 |
| Marineband Limited | Extraterritorial | 2012 |
| Marinecase Limited | Extraterritorial | 2012 |
| Marinedeck Limited | Extraterritorial | 2012 |
| Marinefirst Limited | Manufacturing | 2013 |
| Marinefresh Limited | Extraterritorial | 2012 |
| Marineglide Limited | Extraterritorial | 2012 |
| Marinehost Limited | Extraterritorial | 2013 |
| Marineport Limited | Extraterritorial | 2012 |
| Marineseal Limited | Extraterritorial | 2012 |