| Mallett & Carter Ltd | Construction | 2025 |
| Mandys Tools Limited | Wholesale & retail | 2014 |
| Mann Made Homes Limited | Construction | 1988 |
| Marathon Cleaning Services Ltd | Extraterritorial | 2011 |
| Marathon Services Limited | Administrative & support | 1995 |
| Marko and SON Ltd | Agriculture & fishing | 2025 |
| Marliemothams Limited | Real estate | 2009 |
| Marquees of Wisbech Limited | Administrative & support | 2012 |
| Marshland Stoves Limited | Construction | 1998 |
| Martin Reynolds Construction Limited | Professional & scientific | 2002 |
| Mason Grove Limited | Real estate | 2024 |
| Maverick Recruitment Limited | Information & communication | 2019 |
| MAY Construction Ltd | Construction | 2004 |
| MAY Property Services Limited | Households | 2016 |
| MB Electrical Solutions Ltd | Construction | 2016 |
| MBA High Voltage Holdings Limited | Professional & scientific | 2019 |
| Media Asset Securities Ltd | Professional & scientific | 2018 |
| Meridian 74 Ltd | Financial services | 2021 |
| Merlinward Limited | Real estate | 1996 |
| Millar Mortgages Ltd | Financial services | 2018 |
| Mills & Allen Group Ltd | Professional & scientific | 2020 |
| Mills and Allen Ltd | Professional & scientific | 2019 |
| MJB Building Contractors Limited | Construction | 2013 |
| MJB Suffolk Limited | Professional & scientific | 2021 |
| MJK Imports Ltd | Wholesale & retail | 2023 |
| MJP Electrical Estimating Limited | Public administration | 2014 |
| MKC Osteopathy Limited | Health & social care | 2007 |
| Morris Armitage Dmkt (Rentals) Limited | Real estate | 2012 |
| Mortgage One Solutions Limited | Professional & scientific | 2022 |
| MRC Modular Limited | Manufacturing | 2013 |
| MSN Networks Limited | Information & communication | 2016 |
| Mulready Holdings Limited | Financial services | 2023 |
| Murray Fencing Ltd | Construction | 2022 |
| Muzmuztv Dog Training & Clothing Limited | Wholesale & retail | 2023 |
| Myrrhis Homes Limited | Real estate | 2019 |
| N J Langford Ltd | Wholesale & retail | 2006 |
| NB Safety Services Limited | Professional & scientific | 2026 |
| Nelson West Limited | Professional & scientific | 2013 |
| Nicola Sexton Limited | Wholesale & retail | 2009 |
| NNP Homes Limited | Households | 2026 |
| NO Master Tattoos Limited | Other services | 2021 |
| NO.1 Boleness RD Management Co (Wisbech) Limited | Real estate | 2012 |
| Noah's ARK Trading Ltd | Wholesale & retail | 2024 |
| Nolo Enterprises Ltd | Wholesale & retail | 2023 |
| NOR Cafe Ltd | Hospitality | 2019 |
| Norcam Properties Limited | Construction | 2016 |
| Norfolk Arena Limited | Arts & recreation | 2013 |
| Norfolk Bluebell Wood Limited | Other services | 2013 |
| Norfolk Cake Company Limited | Hospitality | 2013 |
| Norfolk Free Range Limited | Agriculture & fishing | 2003 |
| Norfolk Holiday Lodges Limited | Hospitality | 2006 |
| Norfolk Horizon Limited | Real estate | 2024 |
| Norfolk Leisure Limited | Extraterritorial | 2016 |
| Norfolk Locations Limited | Information & communication | 2020 |
| Norfolk Precious Metals Ltd | Wholesale & retail | 2026 |
| Norfolk Tractors Limited | Agriculture & fishing | 2007 |
| Norfolk Watermill Limited | Wholesale & retail | 2015 |
| NRS Landscape Centre Limited | Administrative & support | 2016 |
| NS Virk Transport Ltd | Transport & logistics | 2025 |
| Ntronix Limited | Professional & scientific | 2008 |
| Obirail Ltd | Construction | 2020 |
| One Stop Drums Limited | Wholesale & retail | 2023 |
| Onlycomps Ltd | Wholesale & retail | 2023 |
| Oodles Entertainment Ltd. | Construction | 2021 |
| Optimum Training Services Limited | Education | 2017 |
| Ouse Bridge Farms Limited | Agriculture & fishing | 1987 |
| Outdoor Antics Ltd | Wholesale & retail | 2013 |
| Outdoor Investors UK Ltd | Real estate | 2015 |
| Outsourced Administration Limited | Financial services | 2025 |
| Outwell Court Ltd | Real estate | 2011 |
| Oyebis Limited | Transport & logistics | 2025 |
| P G Properties DM Limited | Real estate | 2018 |
| P.C.M. Property Care & Maintenance Services Limited | Administrative & support | 2001 |
| P.L.I. Ventures Limited | Construction | 2013 |
| Packwell Properties Limited | Administrative & support | 2018 |
| Pagelines Limited | Construction | 1981 |
| Panoramic Motorhomes Limited | Extraterritorial | 2010 |
| Panther Brewery Limited | Manufacturing | 2020 |
| Paradise Garage DM Limited | Wholesale & retail | 2013 |
| Paradise Garage Motorcycles Limited | Wholesale & retail | 2020 |
| Parker Eyecare Ltd | Health & social care | 2014 |
| Passive Homes (Norfolk) Limited | Professional & scientific | 2007 |
| Pater Limited | Wholesale & retail | 2013 |
| Paul Crawford Consultancy Limited | Financial services | 2003 |
| Payright Payroll Limited | Administrative & support | 2013 |
| Pearl & Dean Outdoor Ltd | Professional & scientific | 2024 |
| Pearl and Dean Ltd | Professional & scientific | 2020 |
| Penny Viking Limited | Extraterritorial | 2017 |
| PEP55 Limited | Other services | 2019 |
| Perry Copeland Limited | Information & communication | 2015 |
| Peter Bates Holistic Books Limited | Information & communication | 2025 |
| Peter Bates Holistic Services Limited | Health & social care | 2024 |
| Peter Knight Housebuilding Ltd | Construction | 2025 |
| PG & JG Consultancy Ltd | Professional & scientific | 2024 |
| PGM Properties DM Limited | Real estate | 2024 |
| Pills and Quills Ltd | Professional & scientific | 2015 |
| Pims Plastics Limited | Manufacturing | 2014 |
| Pine Farm Holdings Ltd | Financial services | 2025 |
| PJ Industrial Solutions Ltd | Professional & scientific | 2019 |
| Polestar Enterprises Limited | Construction | 2014 |