| MLB Pacific Limited | Professional & scientific | 2025 |
| MLC Building Maintenance Limited | Construction | 2001 |
| MLC Properties Limited | Real estate | 2004 |
| MLD Solutions Limited | Transport & logistics | 2016 |
| MLE Electrical Ltd | Construction | 2022 |
| MLE Investments & Property Management Ltd | Real estate | 2025 |
| MLF Investments (New Forest) Ltd | Professional & scientific | 2021 |
| MLJ Car Services Limited | Wholesale & retail | 2020 |
| MLJ Cars Services Limited | Other services | 2022 |
| MLJ Garage Ltd | Other services | 2023 |
| MLJ Limited | Real estate | 2025 |
| MLK 35 Limited | Hospitality | 2026 |
| MLM Engineering & Consulting Ltd | Professional & scientific | 2019 |
| Mlogix Limited | Information & communication | 2025 |
| MLS Landscapes Ltd | Administrative & support | 2022 |
| MM Accounting & Advisory (UK) Ltd | Professional & scientific | 2014 |
| MM Accounts Limited | Professional & scientific | 2022 |
| MM Construct Ltd | Construction | 2021 |
| MM Drinks Ltd | Wholesale & retail | 2017 |
| MM Hants Ltd | Real estate | 2016 |
| MM Leadership Ltd | Professional & scientific | 2026 |
| MM Painting and Decorating Ltd | Construction | 2025 |
| MM Performance Cars Limited | Wholesale & retail | 2023 |
| MM Performance Limited | Other services | 2018 |
| MM PUB Company Limited | Hospitality | 2024 |
| MM Sales and Lettings Ltd | Households | 2008 |
| MMA Financial Management Limited | Professional & scientific | 2017 |
| MMC Capital Partners Ltd | Professional & scientific | 2025 |
| Mmcz Company Limited | Transport & logistics | 2021 |
| Mmd-Uk Ltd | Manufacturing | 2024 |
| Mmdk Ltd | Extraterritorial | 2023 |
| MMF Solutions Ltd | Extraterritorial | 2010 |
| MMG Transport Limited | Transport & logistics | 2018 |
| Mmilo Modern Furniture Ltd | Wholesale & retail | 2018 |
| MMJ Car Services Limited | Wholesale & retail | 2020 |
| MMK Consulting Ltd | Professional & scientific | 2017 |
| Mmore Holdings Limited | Financial services | 2024 |
| MMS UK Trader Limited | Wholesale & retail | 2025 |
| Mmuk Agricultural & Plant Ltd | Manufacturing | 2019 |
| Mmutanda Health Limited | Health & social care | 2022 |
| MMW Haulage Ltd | Transport & logistics | 2016 |
| MMW Mario Limited | Transport & logistics | 2016 |
| MN Energy Ltd | Energy | 2016 |
| MN Horizons Limited | Administrative & support | 2018 |
| MN Painting & Decorating Ltd | Construction | 2025 |
| Mnea Developments Limited | Real estate | 2026 |
| MNG Maritime Ltd | Administrative & support | 2012 |
| MNG S200 Limited | Administrative & support | 2017 |
| MNK Spaces Ltd | Real estate | 2023 |
| MNO Logistics Ltd | Transport & logistics | 2025 |
| MNP Entertainment Ltd | Hospitality | 2016 |
| MNP Installations Ltd | Construction | 2012 |
| MNP Properties Limited | Extraterritorial | 2017 |
| MNS Solent Limited | Hospitality | 2021 |
| Mnsla Plumbing and Heating Ltd | Construction | 2015 |
| Mnsla Property Limited | Real estate | 2025 |
| MO & Sons Technologies Ltd | Information & communication | 2026 |
| MO Cars 5STAR Ltd | Wholesale & retail | 2025 |
| MO Realisations Limited | Administrative & support | 2012 |
| Mobile Auto Tech Limited | Wholesale & retail | 2019 |
| Mobile Dental Care Ltd | Extraterritorial | 2015 |
| Mobile Mechanic Truck Ltd | Wholesale & retail | 2023 |
| Mobile Motor Clinic Ltd | Wholesale & retail | 2021 |
| Mobile Repair Shop Ltd | Other services | 2026 |
| Mobile Zone Southampton Ltd | Wholesale & retail | 2024 |
| Mobilebonus Limited | Manufacturing | 1994 |
| Mobius Vortex (IP) Ltd | Professional & scientific | 2026 |
| Mobius Vortex Engineering Ltd | Professional & scientific | 2026 |
| Mobius Vortex Group Ltd | Financial services | 2026 |
| Mobius Vortex Ltd | Manufacturing | 2024 |
| Mobius Vortex Research Ltd | Manufacturing | 2026 |
| Mobley Engineering Solutions Ltd | Professional & scientific | 2021 |
| Mobor Ltd | Wholesale & retail | 2018 |
| Mocamrahp Limited | Professional & scientific | 1999 |
| Mocarft Ltd | Wholesale & retail | 2026 |
| Mockingjay Ltd | Wholesale & retail | 2018 |
| Mocom Systems Limited | Manufacturing | 1984 |
| Moda Ricca Ltd | Wholesale & retail | 2025 |
| Mode:Zentz Ltd | Manufacturing | 2024 |
| Modecraft Ltd | Wholesale & retail | 2025 |
| Model Tourism Ltd | Information & communication | 2020 |
| Moderat Limited | Information & communication | 2022 |
| Modern Light Room Extensions Ltd | Construction | 2022 |
| Modern Technologies Limited | Professional & scientific | 2010 |
| Modern Urban Living Limited | Transport & logistics | 2008 |
| Modesto Group Ltd | Wholesale & retail | 2025 |
| Modexa Global Ltd | Administrative & support | 2025 |
| Modfashion GS Ltd | Wholesale & retail | 2024 |
| Modnalash Ltd | Wholesale & retail | 2023 |
| Modnas Limited | Construction | 2019 |
| Modo Recruitment Ltd | Administrative & support | 2023 |
| Modomics Ltd | Professional & scientific | 2022 |
| Moeller and Partner UK Limited | Transport & logistics | 2007 |
| Moga Logistics Ltd | Construction | 2021 |
| Mogal Pratap Ltd | Hospitality | 2021 |
| Mogc Ltd | Arts & recreation | 2008 |
| Mogstar Limited | Professional & scientific | 2012 |
| Mohga Ltd | Manufacturing | 2024 |
| Moied Property Investments Ltd | Real estate | 2020 |
| Mokgosi Ltd | Health & social care | 2022 |