| Maxim Telecommunications Limited | Information & communication | 2005 |
| MB (GX) Ltd | Households | 2019 |
| Mcafee Consulting Ltd | Professional & scientific | 2022 |
| Mcclure Homes Limited | Real estate | 2020 |
| Mcintyre Properties Ltd | Real estate | 2013 |
| Mdihub Ltd | Other services | 2017 |
| ME and My Pet-Online Ltd | Wholesale & retail | 2024 |
| Mead Tech Ltd | Extraterritorial | 2016 |
| MEDIA68 Ltd | Wholesale & retail | 2025 |
| Meraki Financial Planning Limited | Financial services | 2019 |
| Meraki HR Consultancy Ltd | Professional & scientific | 2021 |
| Mercer LAL Ltd. | Information & communication | 2009 |
| Meredith House Limited | Manufacturing | 2025 |
| Meronwest Limited | Real estate | 1999 |
| Merrell Mechanical Limited | Construction | 2012 |
| Merritsuko Consultancy Ltd | Financial services | 2023 |
| Metchar Ltd | Wholesale & retail | 2019 |
| MGH Investments Limited | Administrative & support | 1998 |
| Migarctig Limited | Professional & scientific | 2020 |
| Migrationware Limited | Professional & scientific | 2001 |
| Milford Agencies Ltd | Real estate | 2009 |
| Milk & Bean LLP | | 2023 |
| Miroglio (U.K.) Limited | Wholesale & retail | 1975 |
| Mission Datalabs Ltd | Information & communication | 2016 |
| Mitco Ltd | Information & communication | 2012 |
| MK Bowls Limited | Education | 2025 |
| MKR Property Limited | Real estate | 2015 |
| MNH Systems Ltd | Information & communication | 2014 |
| Mode Networks Ltd | Information & communication | 2013 |
| Molesey Properties Limited | Real estate | 2011 |
| Molondas Limited | Professional & scientific | 2011 |
| Monbon Ltd | Financial services | 2024 |
| Mondial Display & Exhibitions Limited | Construction | 1997 |
| Monroe Homes H.R Limited | Construction | 2024 |
| Montagne Ltd | Wholesale & retail | 2023 |
| Montreal Consulting Limited | Professional & scientific | 2019 |
| Monty Christo Investments Ltd | Real estate | 2011 |
| Moon and Stars (Beverages) Ltd | Hospitality | 2022 |
| Moore-Gwyn Fine Art Limited | Wholesale & retail | 2007 |
| Morabeza Ltd | Wholesale & retail | 2024 |
| Morgan Richards Property Limited | Construction | 2023 |
| Mortgage Tracker Limited | Financial services | 2014 |
| Mortimer Technology Group Limited | Manufacturing | 2003 |
| Mortimer Technology Holdings Limited | Professional & scientific | 1988 |
| Morton Statistical Services Limited | Information & communication | 2021 |
| Motivate & Aspire Ltd | Administrative & support | 2021 |
| Mottashaw Consulting Limited | Education | 2009 |
| Mouton Global Limited | Information & communication | 2008 |
| Moville Insights Ltd | Professional & scientific | 2022 |
| Mown and Grown Grounds Maintenance Limited | Administrative & support | 2018 |
| MPS Accountancy & Tax Ltd | Professional & scientific | 2006 |
| MR Jackets Spud Garden Ltd | Hospitality | 2026 |
| MRP Transport Ltd | Transport & logistics | 2025 |
| MS (GB) Ltd | Wholesale & retail | 2013 |
| MS Project Services Limited | Professional & scientific | 2001 |
| MSV Consultants Ltd | Administrative & support | 2017 |
| Mt-Luc Limited | Health & social care | 2022 |
| Mtaba Limited | Professional & scientific | 2002 |
| Mukked Ltd | Wholesale & retail | 2023 |
| Multigreen Limited | Professional & scientific | 2013 |
| Multiplan Consultants Limited | Information & communication | 1990 |
| Mustang Bass Properties Ltd | Real estate | 2022 |
| MWG Technologies Ltd | Information & communication | 2006 |
| MWS Media Ltd | Information & communication | 2007 |
| My Pet Online Ltd | Wholesale & retail | 2023 |
| My Story Organisation Community Interest Company | Information & communication | 2024 |
| N Brown Consulting Ltd | Professional & scientific | 2019 |
| N.L.Builder Limited | Construction | 2014 |
| Nakena Consultancy Limited | Professional & scientific | 2022 |
| NAS Environmental Engineering Ltd | Professional & scientific | 2022 |
| Nashy Limited | Financial services | 2021 |
| Natasha Marsh Hairdressing Limited | Other services | 2023 |
| National Association of Street Artists UK C.I.C. | Arts & recreation | 2018 |
| National Association of Teachers of Dancing Limited(The) | Professional & scientific | 1952 |
| National Rural Touring Forum | Arts & recreation | 1997 |
| Navsales Ltd | Wholesale & retail | 2026 |
| NCK Investments Limited | Professional & scientific | 1948 |
| Neil Ballard Properties Ltd | Real estate | 2020 |
| Neil Bremner Electrical Services Limited | Construction | 2015 |
| NET4ORCE Services Limited | Information & communication | 2016 |
| Netmate.Com Limited | Professional & scientific | 2000 |
| New Pangea Limited | Education | 2022 |
| Newbrook Limited | Real estate | 2022 |
| Newbury 4X4 Centre Limited | Wholesale & retail | 2013 |
| Newbury and District Hackspace | Other services | 2016 |
| Newbury Building Services Ltd | Construction | 2018 |
| Newbury Cars (West Berkshire) Ltd | Administrative & support | 2023 |
| Newbury Cars Ltd | Administrative & support | 2023 |
| Newbury Commercial Services Ltd | Construction | 2021 |
| Newbury Fitting Centre Limited | Wholesale & retail | 2010 |
| Newbury GIN Limited | Manufacturing | 2016 |
| Newbury Property Maintenance Limited | Construction | 2014 |
| Newbury Ymca | Health & social care | 2002 |
| Nexphara Ltd | Professional & scientific | 2026 |
| Next Generation Football Player Ltd | Arts & recreation | 2022 |
| Ngamiland Explorations Limited | Hospitality | 2015 |
| Nice Homes Limited | Construction | 1999 |
| Nigel Cowley Limited | Information & communication | 2005 |
| Njpenterprises (2012) Limited | Information & communication | 2012 |
| NK Agile Engineering Consulting Ltd | Information & communication | 2024 |