| M G Easton & Sons Ltd | Financial services | 2022 |
| M G Mecca Limited | Wholesale & retail | 2011 |
| M Itcs Limited | Professional & scientific | 2008 |
| M J Developments Limited | Real estate | 2018 |
| M J Grimes Electrical Ltd | Construction | 2007 |
| M J Tilney Ltd | Agriculture & fishing | 2012 |
| M J Walker Properties Limited | Real estate | 2019 |
| M J Wright Utilities Limited | Transport & logistics | 2007 |
| M Jaff Ltd | Other services | 2022 |
| M Jallow & SON Service Ltd | Health & social care | 2017 |
| M L Daws Ltd | Construction | 2012 |
| M Libano Property Limited | Real estate | 2018 |
| M Lockwood Construction Limited | Construction | 2022 |
| M Longe Limited | Real estate | 2010 |
| M M Sheikh Properties Ltd | Real estate | 2026 |
| M P Cattle Services Limited | Professional & scientific | 2012 |
| M P Enterprise Ltd | Hospitality | 2017 |
| M P J Building Services Limited | Professional & scientific | 2013 |
| M Pack Engineering Ltd | Manufacturing | 2005 |
| M Plaza Construction Ltd | Construction | 2018 |
| M Plus Holdings Ltd | Financial services | 2025 |
| M Plus PFS Ltd | Financial services | 2025 |
| M Powles Limited | Administrative & support | 2011 |
| M R Holdings (Anglia) Limited | Professional & scientific | 2018 |
| M T G Solutions Limited | Manufacturing | 2015 |
| M T Spice Ltd | Hospitality | 2024 |
| M W D Electrical Services Ltd | Construction | 2016 |
| M W Logistcs Norwich Limited | Transport & logistics | 2017 |
| M W Snare Plant Hire Limited | Agriculture & fishing | 2011 |
| M Warren Solutions Limited | Professional & scientific | 2025 |
| M Wells Social Limited | Information & communication | 2024 |
| M&A Brun Ltd | Hospitality | 2019 |
| M&A Corporate Finance Limited | Extraterritorial | 2011 |
| M&D Insulation Ltd | Construction | 2018 |
| M&F Group Limited | Financial services | 2025 |
| M&F Interiors & Vinyl Ltd | Professional & scientific | 2019 |
| M&H Electrical Contractor Services Limited | Construction | 2024 |
| M&J Engineering Ltd | Wholesale & retail | 2020 |
| M&L Plasterers EA Limited | Construction | 2022 |
| M&L Property Co. Ltd | Real estate | 2026 |
| M&M Enterprise Holdings Ltd | Other services | 2025 |
| M&M Food (Norfolk) Ltd | Hospitality | 2024 |
| M&M Hire Limited | Administrative & support | 2012 |
| M&M Properties Norwich Limited | Administrative & support | 2025 |
| M&M Sweet Treats Ltd | Wholesale & retail | 2024 |
| M&Max Ltd | Transport & logistics | 2025 |
| M&Nplumbing Ltd | Construction | 2013 |
| M&P Online Limited | Wholesale & retail | 2025 |
| M&P Transport Service Ltd | Transport & logistics | 2020 |
| M&R Developments Eastern Ltd | Real estate | 2018 |
| M&R Heating and Cooling Ltd | Construction | 2020 |
| M&T&Co Ltd | Professional & scientific | 2022 |
| M'S Creamy Gelato Limited | Hospitality | 2016 |
| M'S of Aylsham Ltd | Wholesale & retail | 2021 |
| M-Tech Auto Solutions Ltd | Wholesale & retail | 2020 |
| M. Breeze Electrical Limited | Manufacturing | 2008 |
| M. Gaze & Co. Limited | Water & waste | 1969 |
| M. Gaze Maintenance Limited | Extraterritorial | 1990 |
| M. K. Repairs Limited | Wholesale & retail | 2003 |
| M. Rituals & Aesthetics Ltd | Health & social care | 2022 |
| M. Ryder Building & Roofing Specialists Limited | Construction | 2014 |
| M. Whiting Builders & Contractors Limited | Construction | 1991 |
| M.A. & H.V. Medler (Haulage) Limited | Transport & logistics | 1978 |
| M.A.D.Design & Build Ltd | Construction | 2016 |
| M.A.P. Builders Norfolk Ltd | Construction | 2024 |
| M.A.Reynolds Ltd | Professional & scientific | 2008 |
| M.C.L. Mechanical Services Limited | Manufacturing | 2004 |
| M.E. Composites Ltd | Professional & scientific | 2015 |
| M.G. Electrical (Norfolk) Ltd | Construction | 2018 |
| M.G.C. Lamps Limited | Manufacturing | 1976 |
| M.J. Autoparts (Norwich) Limited | Wholesale & retail | 1980 |
| M.J.Gladden Digger Hire & Ground Works Ltd | Construction | 2020 |
| M.P. Kemp Limited | Agriculture & fishing | 1979 |
| M.R Fencing (Calne) Ltd | Administrative & support | 2014 |
| M.R. Ellis (Timber) Limited | Manufacturing | 1974 |
| M.R. Scaffolding (Anglia) Limited | Construction | 1994 |
| M.S. and S. Graver Ltd | Water & waste | 2006 |
| M.T.B Foods Ltd | Hospitality | 2021 |
| M.T.M Projects Ltd | Construction | 2022 |
| M.W. White (Norwich) Limited | Extraterritorial | 1965 |
| M.W. White Limited | Water & waste | 2010 |
| M2 Construction Limited | Construction | 2015 |
| M29 Digital Ltd | Transport & logistics | 2024 |
| M7 Design Limited | Professional & scientific | 2016 |
| M8R Limited | Professional & scientific | 2019 |
| MA Partners Accountants Limited | Extraterritorial | 2011 |
| MA Partners Audit LLP | | 2019 |
| MA Partners LLP | | 2011 |
| MA Solicitors Limited | Professional & scientific | 2011 |
| MA UK Trans Ltd | Transport & logistics | 2020 |
| Maace Residential Ltd | Real estate | 2008 |
| Maaj Ltd | Real estate | 2023 |
| Maaz Trading UK Ltd | Wholesale & retail | 2020 |
| Mabel 27 Ltd | Health & social care | 2020 |
| Mabel Gray (Holt) Limited | Administrative & support | 2009 |
| Maby Group Ltd | Manufacturing | 2015 |
| MAC 1 Ltd | Construction | 2023 |
| MAC 10 Marketing Limited | Professional & scientific | 2022 |
| MAC Care Agency Limited | Health & social care | 2017 |
| Mac's Maintenance Services Limited | Construction | 2024 |