| Mckibbin Management Consultants Limited | Administrative & support | 2002 |
| Md-Reproductive Health Solutions Ltd | Wholesale & retail | 2015 |
| MEA Solutions Ltd | Professional & scientific | 2019 |
| Medinform Limited | Information & communication | 2000 |
| Merv's Hot Bread Kitchen Limited | Wholesale & retail | 2003 |
| Miller Installations Ltd | Construction | 2020 |
| Milne Marketing Limited | Administrative & support | 1996 |
| Mindspan Global Limited | Education | 2013 |
| Minnows 4959 Limited | Households | 2018 |
| Missy's Hair Ltd | Other services | 2018 |
| Mitchell Building Services Limited | Construction | 2012 |
| MJA Media Ltd | Information & communication | 2026 |
| ML Financial Associates Limited | Financial services | 2010 |
| Ml-One Engineering Limited | Professional & scientific | 2016 |
| MN Landscapes Limited | Administrative & support | 2023 |
| Mode and Deima Ltd | Wholesale & retail | 2025 |
| MOH Developments Ltd | Real estate | 2023 |
| Momnt Sports Ltd | Information & communication | 2025 |
| Mond Kebab Ltd | Hospitality | 2026 |
| Moneyproperties Limited | Real estate | 2003 |
| Moneyresidential Limited | Real estate | 2020 |
| Mont Bray Ltd | Real estate | 2017 |
| Moonboots Consultancy UK Ltd | Information & communication | 2024 |
| Moore Solutions Holdings UK Ltd | Financial services | 2025 |
| More to Store Limited | Transport & logistics | 2021 |
| Morgan Price Healthcare (International) Limited | Extraterritorial | 2002 |
| Morgan Price Healthcare (UK) Limited | Extraterritorial | 2002 |
| Morgan Price International Healthcare Limited | Financial services | 1999 |
| Morgan Price Property Limited | Real estate | 2002 |
| Morley Farms Limited | Agriculture & fishing | 2003 |
| Morley Nurseries Limited | Agriculture & fishing | 1964 |
| Mosaic London Studios and Apartments Limited | Real estate | 2015 |
| Mother Cosmos Ltd | Hospitality | 2025 |
| Motion Health and Wellness Limited | Health & social care | 2017 |
| Moto-Electrical Limited | Extraterritorial | 2012 |
| Moulam Enterprises Limited | Information & communication | 2020 |
| Mould Detectives Limited | Other services | 2018 |
| MR Overalls Limited | Manufacturing | 2013 |
| MRH Service Centre Ltd | Wholesale & retail | 2025 |
| MRM Accountants Ltd | Professional & scientific | 2024 |
| MTL Financial Services Limited | Financial services | 2020 |
| Mulberry Build Ltd | Construction | 2021 |
| Multimatic CFT Limited | Manufacturing | 1994 |
| Mustard Digital Services Limited | Professional & scientific | 2018 |
| Muzire Healthcare Limited | Health & social care | 2014 |
| My Personal Finance UK Ltd | Financial services | 2025 |
| Mycontentions Ltd | Extraterritorial | 2021 |
| N & T Brown Roofing Ltd | Construction | 2012 |
| N J Myhill Architecture Ltd | Professional & scientific | 2025 |
| N W Ground Work and Services Ltd | Construction | 2019 |
| N.A.L. Properties Ltd | Construction | 2007 |
| N10 Agency Ltd | Professional & scientific | 2023 |
| NAM Thai Limited | Hospitality | 2025 |
| Nature Recovery Partners Ltd | Professional & scientific | 2025 |
| NBB Tech Ltd | Information & communication | 2022 |
| NCS Pipeline & Engineering Ltd | Professional & scientific | 2025 |
| Netmatters Limited | Information & communication | 2008 |
| New Creation Star 21 Ltd | Health & social care | 2017 |
| New Form Construction Ltd | Manufacturing | 2016 |
| New Tyneside Investments Limited | Real estate | 1959 |
| NF Agri Limited | Professional & scientific | 2019 |
| NFM Properties Limited | Real estate | 2001 |
| Ngct Services Limited | Administrative & support | 2020 |
| Nhbt Trading Company Limited | Arts & recreation | 2020 |
| Nick Lane Marketing Limited | Professional & scientific | 2012 |
| Nimbus-Bookkeeping Ltd | Professional & scientific | 2021 |
| NMG Motor Engineers Limited | Wholesale & retail | 2025 |
| NNT Services Ltd | Construction | 2024 |
| Norfolk and Norwich Vascular Limited | Health & social care | 2018 |
| Norfolk Avenue Social Limited | Professional & scientific | 2024 |
| Norfolk Chiropractic Limited | Health & social care | 2026 |
| Norfolk Clean Services Ltd | Administrative & support | 2025 |
| Norfolk Fabrication & Maintenance Limited | Transport & logistics | 1997 |
| Norfolk Fire & Security Limited | Administrative & support | 2013 |
| Norfolk Health, Wellbeing and Forensic Services Ltd | Health & social care | 2018 |
| Norfolk Heart Rhythm Limited | Health & social care | 2018 |
| Norfolk Historic Buildings Trust | Other services | 1977 |
| Norfolk Information Services Limited | Professional & scientific | 2003 |
| Norfolk Nest Properties Ltd | Real estate | 2026 |
| Norfolk Network Limited | Other services | 2012 |
| Norfolk News Deliveries Limited | Wholesale & retail | 2007 |
| Norfolk Pelvic Health Ltd. | Professional & scientific | 2022 |
| Norfolk Premium Driveways Ltd | Construction | 2017 |
| Norfolk Sheet Lead (UK) Limited | Manufacturing | 2012 |
| Norfolk Soulstice Ltd | Information & communication | 2026 |
| Norfolkfootball Ltd | Wholesale & retail | 2015 |
| North & Hawkins Ltd | Professional & scientific | 2015 |
| North Norfolk Property Limited | Real estate | 2017 |
| Novatura Ltd | Information & communication | 2023 |
| Nurctus Limited | Administrative & support | 2022 |
| Nurcu Ltd | Hospitality | 2025 |
| NVP Access Hire Limited | Construction | 2013 |
| Oaks Cctv Limited | Other services | 1996 |
| Oaktree Business Space Ltd | Construction | 2004 |
| Oakwinch Limited | Professional & scientific | 2011 |
| Oakwood Developments (EA) Ltd | Construction | 2025 |
| Ocean Point Aviation Services Limited | Transport & logistics | 2021 |
| Ohmz Distro Limited | Wholesale & retail | 2015 |
| OJ Civils Ltd | Construction | 2022 |
| OMG Consulting (Norfolk) Ltd | Information & communication | 2020 |