| LW Plant Limited | Construction | 2022 |
| Lwfoley Limited | Professional & scientific | 2009 |
| Lyfield Court (Bookham) Residents Management Company Limited | Households | 2016 |
| Lynda Mills Kitchens Limited | Construction | 2018 |
| M & B Leatherhead Holdings Limited | Financial services | 2020 |
| M & K Enterprises Limited | Hospitality | 2003 |
| M Fletcher Limited | Professional & scientific | 2022 |
| M N Properties (Southern) Limited | Real estate | 2003 |
| M T Home and Garden Ltd | Construction | 2021 |
| M-G-G Security Ltd | Administrative & support | 2025 |
| M-Mgmt Limited | Administrative & support | 2012 |
| M. Edge Services Ltd | Manufacturing | 2016 |
| M. I. G. S. Ltd. | Manufacturing | 1998 |
| M. Moen & Sons Limited | Extraterritorial | 2004 |
| M.B. (Production) Engineering Limited | Manufacturing | 1994 |
| M.I.N Digital Ltd | Professional & scientific | 2022 |
| M.P. Secretaries Limited | Extraterritorial | 1994 |
| M1 Performance Coaching Ltd | Professional & scientific | 2016 |
| MAC Smarter Research Ltd | Professional & scientific | 2026 |
| Mac-I Limited | Professional & scientific | 2001 |
| Macarthur Ventures Ltd | Information & communication | 2025 |
| Macedo (UK) Limited | Wholesale & retail | 1994 |
| Machado Industries Ltd | Professional & scientific | 2022 |
| Macram Solutions Limited | Professional & scientific | 2015 |
| Macs Autocare Services Limited | Wholesale & retail | 2014 |
| Madeira Joiners Ltd | Construction | 2023 |
| Madia Investments Limited | Households | 1961 |
| Madison Close Management Company Limited | Households | 2006 |
| Madjik Limited | Professional & scientific | 2011 |
| Magic Paint Shop Ltd | Wholesale & retail | 2020 |
| Magic Scissors Dorking Ltd | Other services | 2024 |
| Magic Scissors Dorkingg Ltd | Other services | 2026 |
| Major 5TH Consultancy Ltd | Professional & scientific | 2025 |
| MAL Biomass Ltd | Construction | 2025 |
| Mallison Homes Ltd | Households | 2025 |
| Maltby Mason Property LLP | | 2023 |
| Maltbys Estates Ltd | Real estate | 2025 |
| Malu ME Limited | Wholesale & retail | 2019 |
| Malzm GMO Ltd | Wholesale & retail | 2024 |
| Mamba Media Ltd | Professional & scientific | 2010 |
| Maneo P&Fs Limited | Professional & scientific | 2017 |
| Mangomoon Ltd | Professional & scientific | 2024 |
| Manning Dene Street Limited | Real estate | 2017 |
| Manor Cookery Limited | Administrative & support | 2003 |
| Mansell Leisure Services Limited | Construction | 2006 |
| Maple Court Residents Management Company Limited | Households | 1998 |
| Maplerose Equestrian Limited | Education | 2023 |
| Mapperson Price Limited | Professional & scientific | 1994 |
| Mapral Limited, | Real estate | 1963 |
| Mar-Gel(Food Products)Limited | Transport & logistics | 1973 |
| Maranello House (Residents) Limited | Households | 2006 |
| Marchena Ltd | Professional & scientific | 2024 |
| Marett Foundations Limited | Real estate | 1992 |
| Margetts Family Holdings Limited | Real estate | 2016 |
| Maria Bullen Marketing Limited | Professional & scientific | 2007 |
| Mariposa Landscapes Ltd | Administrative & support | 2024 |
| Mark Hayman Insurance Services Limited | Financial services | 2005 |
| Mark Savill Transport Limited | Transport & logistics | 2021 |
| Marketing Resources Limited | Administrative & support | 1997 |
| Markham (Capel) Management Company Limited | Households | 1985 |
| Marlborough Court (Ashtead) Management Limited | Households | 2002 |
| Marqs Ltd | Wholesale & retail | 2021 |
| Marsden Rock Consulting Limited | Professional & scientific | 2015 |
| Marsh Electrical Ltd | Construction | 2019 |
| Marsh Homes Limited | Construction | 2020 |
| Martial X Academy (Leatherhead) Ltd | Education | 2023 |
| Martin Grant & Co. Limited | Construction | 1968 |
| Martin Grant Homes (Brentwood) Limited | Construction | 1982 |
| Martin Grant Homes (Essex) Limited | Construction | 1982 |
| Martin Grant Homes (U.K.) Limited | Construction | 1972 |
| Martin Grant Homes Land Limited | Real estate | 1986 |
| Martin Grant Land Limited | Construction | 1978 |
| Martin Knights Consulting Ltd | Professional & scientific | 2017 |
| Martin Rootes Ltd | Information & communication | 2014 |
| MAS South Limited | Professional & scientific | 2025 |
| Mason Mabon Ltd | Manufacturing | 2016 |
| Masons Paddock (Residents Association) Limited | Other services | 1976 |
| Masose FM Ltd | Administrative & support | 2011 |
| Master Blade Ltd | Other services | 2016 |
| Master Craft (U.K.) Limited | Construction | 1983 |
| Master Industries (2006) Limited | Real estate | 2024 |
| Mater-Ai Limited | Professional & scientific | 2023 |
| Mathieu Barnard Limited | Professional & scientific | 2024 |
| Matmax (UK) Ltd | Construction | 2012 |
| Matoc Limited | Professional & scientific | 2013 |
| Matt Prior Promotions Limited | Professional & scientific | 2007 |
| Matthew Smith Associates Limited | Professional & scientific | 2013 |
| Matthew Staples Dwcf Limited | Agriculture & fishing | 2003 |
| Matthews Associates (UK) Limited | Professional & scientific | 2011 |
| Matts Vehicle Services Ltd | Wholesale & retail | 2025 |
| Maud Vaughan Ltd | Wholesale & retail | 2023 |
| Maultway Court Management Company Limited | Households | 2005 |
| Maxbow Holdings Limited | Households | 2021 |
| Maxel Projects Limited | Construction | 2018 |
| Mayes Park Holdings Ltd | Financial services | 2022 |
| Mayes Park Ltd | Real estate | 2021 |
| Mayfield Court (Tollgate) Management Limited | Households | 1987 |
| Maysap Group Ltd | Financial services | 2022 |
| Mccutcheon Ltd | Information & communication | 2014 |
| Mcgregor Insurance Services Limited | Financial services | 2003 |