| Luxe Nest Furniture Ltd | Other services | 2025 |
| Lynton & Lynton Limited | Administrative & support | 2022 |
| Lynx Andover Ltd | Real estate | 2017 |
| Lynx UK Limited | Information & communication | 2004 |
| Lytton Ecosystems Ltd | Professional & scientific | 2026 |
| LZN Services Limited | Real estate | 2022 |
| M & S Facilitation PVT Ltd | Real estate | 2014 |
| M a Hinton Roofing Ltd | Construction | 2003 |
| M Aldridge Services Ltd | Other services | 2025 |
| M Allen Roofing Limited | Construction | 2023 |
| M and M Property (South) Limited | Construction | 2014 |
| M Fisher Engineering Limited | Professional & scientific | 2007 |
| M G T the Gaugemakers Limited | Manufacturing | 1991 |
| M J Startup & Co Limited | Professional & scientific | 2002 |
| M K Carpentry South Ltd | Construction | 2020 |
| M Tours Limited | Administrative & support | 2026 |
| M&A Logistics Ltd | Transport & logistics | 2018 |
| M&Art Developments Ltd | Construction | 2026 |
| M&J Inspired Ltd | Health & social care | 2015 |
| M&R Boboc Transport Ltd | Transport & logistics | 2025 |
| M.A.G Trading Ltd | Wholesale & retail | 2025 |
| M2G Consulting Ltd | Professional & scientific | 2012 |
| M3 Automotive Services Ltd | Wholesale & retail | 2026 |
| MA Stringer Consulting Limited | Professional & scientific | 2017 |
| MAC DI Landl Limited | Information & communication | 2025 |
| Macglory Consult Limited | Financial services | 2013 |
| Mach One Consulting Limited | Professional & scientific | 2024 |
| Maciejw Transport Ltd | Transport & logistics | 2021 |
| Maddocks Property Limited | Real estate | 2025 |
| Made by Padel Ltd | Arts & recreation | 2025 |
| Madlen Investments Limited | Real estate | 1961 |
| Madu Media Ltd | Arts & recreation | 2025 |
| Magenta Consulting and Recruitment Ltd. | Administrative & support | 2008 |
| MAH Consultancy (South) Limited | Other services | 2021 |
| Maid in Minutes Ltd | Administrative & support | 2022 |
| Maison Cilla Ltd | Real estate | 2025 |
| Maison Malestroit Limited | Construction | 2006 |
| Maivi Ltd | Other services | 2026 |
| Malcolm Hill Management Limited | Construction | 2020 |
| Malden Window Cleaning Ltd | Administrative & support | 2017 |
| Malepex Limited | Transport & logistics | 2014 |
| Mali & Marley Ltd | Information & communication | 2023 |
| Mallorca Developments Limited | Financial services | 2023 |
| Mambacare Limited | Households | 2021 |
| Managed by Design Ltd | Construction | 2020 |
| Mandimarkus Ltd | Wholesale & retail | 2026 |
| Mania Cards Limited | Wholesale & retail | 2023 |
| Manole Liviu Ltd | Transport & logistics | 2011 |
| Manufacturing Engineering Works Limited | Professional & scientific | 2012 |
| Manuka Blue Ltd | Real estate | 2020 |
| Manzas Enterprises Ltd | Wholesale & retail | 2023 |
| Mapilio Ltd | Wholesale & retail | 2022 |
| Maple Greg Ltd | Transport & logistics | 2022 |
| Mappetite App Limited | Information & communication | 2025 |
| Marcelino Trans Limited | Transport & logistics | 2013 |
| Marders Yard Limited | Real estate | 2023 |
| Marek Kumancik Ltd | Transport & logistics | 2018 |
| Marianpol Ltd | Transport & logistics | 2018 |
| Marithold Limited | Real estate | 1999 |
| Mark 2 Bikes Ltd | Wholesale & retail | 2016 |
| Mark Stanton Physical Conditioning Limited | Other services | 2012 |
| Mark Stockwell Osteopathy Ltd | Health & social care | 2023 |
| Marlborough Hill Portfolio Limited | Financial services | 2025 |
| Marlborough Investment Property Group Ltd | Real estate | 2023 |
| Marmar Cleaning Ltd | Administrative & support | 2025 |
| Marshall & Willes Ltd | Construction | 2019 |
| Marshall James Associates Ltd | Professional & scientific | 2024 |
| Marston Events Limited | Manufacturing | 2005 |
| Marston Events Media Limited | Professional & scientific | 2022 |
| Marston Limited | Manufacturing | 2009 |
| Marston-On-Dove Estates Limited | Real estate | 1952 |
| Martial Art World Limited | Arts & recreation | 2022 |
| Martin and Walker Limited | Manufacturing | 1997 |
| Martin Thomas Limited | Other services | 2013 |
| Marzano Films Limited | Information & communication | 2015 |
| Masada Ecology Limited | Professional & scientific | 2023 |
| Masksafe Ltd | Manufacturing | 2020 |
| Mason Comms Limited | Information & communication | 2008 |
| Master Traditional Turkish Barbers Ltd | Other services | 2022 |
| Masterplanco Ltd | Information & communication | 2026 |
| Mastrans Ltd | Transport & logistics | 2016 |
| Mateika Properties Ltd | Construction | 2024 |
| Mateusz Courier Limited | Transport & logistics | 2018 |
| Mathomas Limited | Wholesale & retail | 2025 |
| Matshala Limited | Extraterritorial | 2023 |
| Matt Duke Sculpture Limited | Arts & recreation | 2017 |
| Mattermoon Ltd | Wholesale & retail | 2024 |
| MAV Clarke Ltd | Construction | 2024 |
| MAX Barham Recruitment Ltd | Administrative & support | 2021 |
| Maxluc Ltd | Wholesale & retail | 2018 |
| MAY Accounting Consulting Ltd | Real estate | 2006 |
| May's Savoury Limited | Hospitality | 2019 |
| Maya Cargo Ltd | Transport & logistics | 2019 |
| Mayagra Ltd | Wholesale & retail | 2025 |
| Mayfly Advisors Limited | Professional & scientific | 2024 |
| Mayhead Limited | Financial services | 2015 |
| MB Enterprise Ltd | Information & communication | 2026 |
| Mbalch Building and Groundworks Ltd | Professional & scientific | 2025 |
| MBC Construction Ltd | Construction | 2025 |
| MBE (Andover) Ltd | Manufacturing | 2015 |