| Manmade Products Limited | Arts & recreation | 1998 |
| Mann Hough Limited | Professional & scientific | 2008 |
| Mannequin Ltd. | Professional & scientific | 2010 |
| Mannequin Properties Ltd | Real estate | 2021 |
| Manor Farm Tea Room Ltd | Hospitality | 2015 |
| Manor Gardens Residents' Land Company Limited | Households | 2007 |
| Manory House Management Company Limited | Households | 1992 |
| Mansell Court (Whitchurch) Management Company Limited | Households | 2007 |
| Mantapix Ltd | Information & communication | 2014 |
| MAP Investments Limited | Administrative & support | 2000 |
| Maple Browns Interiors Ltd | Construction | 2026 |
| Maple Browns Limited | Construction | 2008 |
| Mapps & Co Limited | Financial services | 2014 |
| MAPPS4U Ltd | Information & communication | 2009 |
| Marant Design Ltd | Wholesale & retail | 2014 |
| MARATHON357 Limited | Professional & scientific | 2025 |
| Marbella Lettings Ltd | Real estate | 2017 |
| Marble Hill Group Ltd | Professional & scientific | 2017 |
| Marcel Hendricks & Partners Limited | Construction | 2015 |
| Marchmont Place (Derby Road Haslemere) Residents Management Company Limited | Households | 2026 |
| Marclair Limited | Professional & scientific | 2016 |
| Marcx Limited | Professional & scientific | 2021 |
| Marelands Farms Ltd | Agriculture & fishing | 2019 |
| Margaret Watkins Limited | Real estate | 1992 |
| Maria Shiner Catering Limited | Hospitality | 2013 |
| Mariben Limited | Administrative & support | 2001 |
| Marie Elizabeth Limited | Information & communication | 2023 |
| Marine Publications International Limited | Information & communication | 1981 |
| Marinesee Ltd | Information & communication | 2019 |
| Maritime Leaders Consulting Ltd | Professional & scientific | 2024 |
| Mark Bowditch Accountancy Services Limited | Administrative & support | 2011 |
| Mark Davies Financial Adviser Limited | Financial services | 2019 |
| Mark Garnham Music Ltd | Education | 2014 |
| Mark Huband Consulting Limited | Professional & scientific | 2023 |
| Mark Thomas Spinal Surgery Ltd | Health & social care | 2012 |
| Mark Weller Associates Limited | Financial services | 2012 |
| Mark Wood Golf Academy Ltd | Arts & recreation | 2010 |
| Mark Zimmer Consulting Limited | Information & communication | 2016 |
| Markand Developments Limited | Construction | 2010 |
| Market Inroads Limited | Real estate | 2008 |
| Marketing for Care Ltd | Professional & scientific | 2025 |
| Marketing Results Partnership Limited | Professional & scientific | 2014 |
| Markson Investments Limited | Real estate | 2017 |
| Marley Investments Two Limited | Real estate | 2016 |
| Marlingford Advisory Services Limited | Information & communication | 2017 |
| Marlyn Developments Ltd | Real estate | 2017 |
| Marriott Valuers Limited | Administrative & support | 2018 |
| Marshall Eaton Developments Limited | Construction | 2014 |
| Marshall Eaton Holdings Limited | Professional & scientific | 2017 |
| Marshall Eaton Leisure Limited | Hospitality | 2016 |
| Marston Lodge Management Company Limited | Households | 2017 |
| Martin Bicknell Rights Limited | Arts & recreation | 2000 |
| MAS Global Print Solutions Ltd | Professional & scientific | 2014 |
| Maslow Group Ltd | Real estate | 2021 |
| Mason U.K. Limited | Construction | 1997 |
| Mason UK Holdings Limited | Professional & scientific | 2016 |
| Mastamap Limited | Information & communication | 2016 |
| Master Builders (Southern) Limited | Construction | 1991 |
| Matanius Ltd | Professional & scientific | 2019 |
| Matchmark Limited | Real estate | 1997 |
| Matchpoint Connect Limited | Administrative & support | 2012 |
| Mathias Properties Ltd | Real estate | 2020 |
| Matogen Geospace International Limited | Information & communication | 2022 |
| Matt Chisnall Architectural Photography Ltd | Professional & scientific | 2014 |
| Matt Kurton Words & Ideas Limited | Other services | 2014 |
| Matt Leech Treecare Ltd | Agriculture & fishing | 2022 |
| Matt Lewis Racing Limited | Wholesale & retail | 2012 |
| Matte Box Media Limited | Information & communication | 2011 |
| Matter SFX Limited | Information & communication | 2017 |
| Matterconsult Ltd | Information & communication | 2020 |
| Matthew Beard Financial Services Limited | Financial services | 2018 |
| Matthew Stephenson Arts Limited | Arts & recreation | 2017 |
| Matthew Stephenson Limited | Arts & recreation | 2016 |
| Maudsley Ltd | Professional & scientific | 2017 |
| Maven Executive Coaching and Mentoring Ltd | Professional & scientific | 2008 |
| Mavericks Life Co Ltd | Arts & recreation | 2008 |
| MAX Frimond Consulting Limited | Information & communication | 2013 |
| Maxad Recruitment Ltd | Administrative & support | 2003 |
| Maxbbrown Limited | Information & communication | 2009 |
| Maxima Optics (UK) Limited | Manufacturing | 2000 |
| Maxstim Limited | Wholesale & retail | 2013 |
| Maxwell & Co Limited | Professional & scientific | 1998 |
| Maya Securities Limited | Financial services | 2014 |
| Maybanks Management Company Limited | Households | 2024 |
| Mayd Architecture Limited | Professional & scientific | 2014 |
| Mayd Ltd | Construction | 2021 |
| Mayfair Marquees Group Limited | Other services | 2017 |
| Mayfair Trading Corporation Limited | Wholesale & retail | 1990 |
| Mayfields Residents Management Limited | Households | 1981 |
| Mayfly Associates Limited | Professional & scientific | 2021 |
| Mayfly Construction Ltd | Administrative & support | 2017 |
| Maygate Place Services Limited | Households | 2022 |
| MB Cricket Academy Ltd | Arts & recreation | 2021 |
| MB Investment Estates Ltd | Real estate | 2008 |
| MBI Associates Ltd | Wholesale & retail | 2024 |
| MCA Property Limited | Construction | 2016 |
| Mcainsh Consulting Limited | Professional & scientific | 2007 |
| MCC Construction & Development, Limited | Construction | 2023 |
| Mccabe Building and Groundworks Ltd | Construction | 2003 |
| Mcchina Eating Limited | Hospitality | 2007 |