| Magna Carta Imaging LLP | | 2011 |
| Maida’S Way Residents Association Ltd | Households | 2019 |
| Make IT Terrain Ltd | Manufacturing | 2026 |
| Mama Llama Limited | Information & communication | 2017 |
| Manor Grange Residents Company Limited | Households | 1995 |
| Manuka Court F.M.C. Limited | Households | 1993 |
| Maple & Laurel Court (1993) Limited | Households | 1993 |
| Maple Consulting (Strategic) Ltd | Professional & scientific | 2026 |
| Marine Gold (Europe) Ltd | Wholesale & retail | 2021 |
| Mark Janes Learning Solutions Limited | Administrative & support | 2000 |
| Mark Mathieson Consulting Ltd | Professional & scientific | 2015 |
| Marlow Management Consulting Limited | Professional & scientific | 2023 |
| Marquise Gallery London Ltd | Wholesale & retail | 2026 |
| Masters in Marketing Limited | Professional & scientific | 2015 |
| Matilda TOO Ltd | Administrative & support | 2011 |
| Mavala (U.K.) Limited | Manufacturing | 1970 |
| Maxica Consulting Limited | Professional & scientific | 2013 |
| Maxim Financial Solutions Limited | Financial services | 2003 |
| Maximum Velocity Stunts Limited | Arts & recreation | 2020 |
| Mayhem 14 Limited | Professional & scientific | 2008 |
| MC London Builders Ltd | Construction | 2016 |
| ME & My New Car Limited | Wholesale & retail | 2023 |
| Meadowbarns & Granary Residents Association Limited | Real estate | 1994 |
| MECH2O Engineering Ltd | Construction | 2015 |
| Medtec Design Services Limited | Professional & scientific | 1981 |
| Meetens Industrial Engines Limited | Real estate | 1965 |
| Memberlytics Ltd | Information & communication | 2026 |
| Merzer Properties Ltd | Real estate | 2021 |
| Methodshift Ltd | Information & communication | 2022 |
| MG Web Development Ltd | Information & communication | 2013 |
| MGC Capital Limited | Professional & scientific | 2010 |
| MGC Planning Services Limited | Information & communication | 2006 |
| Mhservices (UK) Limited | Construction | 1997 |
| MI Digital Business Solutions Ltd | Information & communication | 2025 |
| Michaels Consultancy Limited | Professional & scientific | 2026 |
| Michmal Ltd. | Information & communication | 2013 |
| Militoproject Ltd | Wholesale & retail | 2024 |
| Millbrook Court Management Company (Wokingham) Ltd | Households | 2014 |
| Millie Dethick Equine Services Ltd | Other services | 2024 |
| Mission Critical Broadcasting Limited | Information & communication | 2021 |
| Mitchell Property Limited | Real estate | 2016 |
| MJA Hairdressers Ltd | Other services | 2024 |
| MJC1 Limited | Information & communication | 2007 |
| MJC2 Limited | Information & communication | 1990 |
| MJW Plumbing and Heating Ltd | Construction | 2026 |
| MK Services Group Ltd | Real estate | 2018 |
| MM Squared Ltd | Professional & scientific | 2024 |
| Mobile Team Challenge Limited | Professional & scientific | 2002 |
| Modern Vermin Services Limited | Professional & scientific | 1968 |
| Mofomos Limited | Wholesale & retail | 2004 |
| Monkley Court Management Company Limited | Households | 1973 |
| Monster MIX Services Ltd | Construction | 2024 |
| More Than Learning Ltd | Education | 2023 |
| Mortgages by Daniella Limited | Professional & scientific | 2023 |
| Mortimer Hall Ltd | Households | 2000 |
| Mosi Copper Limited | Professional & scientific | 2006 |
| Mphg Limited | Construction | 2014 |
| MTB Management Limited | Arts & recreation | 1996 |
| Mtoko Limited | Administrative & support | 2006 |
| Mulberry Court (Bracknell) Residents Association Limited | Households | 1987 |
| Munchy the Maintenance MAN Ltd | Other services | 2025 |
| Myjobmate Limited | Professional & scientific | 2026 |
| Myriad Coaching and Consulting Limited | Professional & scientific | 2016 |
| N&S Fitness Limited | Arts & recreation | 2013 |
| Nagan Limited | Information & communication | 2011 |
| Nala Pet Services Ltd | Other services | 2026 |
| Nationwide Aluminium Ltd | Administrative & support | 2025 |
| Natural & Pure Ltd | Information & communication | 2015 |
| Natural Fertility Clinic Limited | Health & social care | 2014 |
| Naturedex Limited | Professional & scientific | 2024 |
| NBH Sales Ltd | Wholesale & retail | 2023 |
| Neil Lock Technology Services Limited | Information & communication | 1992 |
| Netfm UK Limited | Information & communication | 2012 |
| Netlink Software | | 1999 |
| Newgen Safety Ltd | Administrative & support | 2023 |
| Nexus Berkshire Ltd | Wholesale & retail | 2023 |
| NGA International Ltd | Construction | 2017 |
| Nhsecurity Ltd | Information & communication | 2010 |
| Nicholas Allder Films Limited | Arts & recreation | 1967 |
| Nigel Ricketts Consulting Ltd | Construction | 2014 |
| Nineteenops Ltd | Professional & scientific | 2023 |
| Niveus Ltd. | Information & communication | 2017 |
| Niveus Property Group Limited | Households | 2025 |
| NO Grey Area Ltd | Construction | 2017 |
| NO TIE Generation Limited | Administrative & support | 2006 |
| NO. 123 Yorktown Road Management Company Limited | Households | 1998 |
| Nochd Limited | Professional & scientific | 2017 |
| Nopf Ltd | Real estate | 2025 |
| NOT Just Socials Ltd | Professional & scientific | 2025 |
| NOT2DAY Ltd | Manufacturing | 2025 |
| Notable Stays Ltd | Hospitality | 2026 |
| Novo-K Limited | Information & communication | 2016 |
| Nutfield Court (Camberley) Management Company Limited | Households | 1986 |
| NV5 Geospatial Solutions UK Limited | Information & communication | 1998 |
| Oakfields Drylining & Plastering Ltd | Construction | 2015 |
| Oakforge Tree Care Ltd | Administrative & support | 2026 |
| Oasislogisticsuk Ltd | Professional & scientific | 2026 |
| Octec Applied Processing Ltd | Professional & scientific | 2023 |
| Oculus Facade Consultancy Limited | Construction | 2007 |
| OG Skinhouse Ltd | Other services | 2025 |