| Martindale Protection Limited | Extraterritorial | 1997 |
| Mashuni Ltd | Information & communication | 2013 |
| Mason Insulation Ltd | Construction | 2022 |
| Master Transport 24/7 Solution Ltd | Transport & logistics | 2023 |
| Masters Training Consultants Limited | Hospitality | 1990 |
| Matt Dobbin Consulting Limited | Professional & scientific | 2024 |
| Maxmerp Limited | Information & communication | 2013 |
| Mayes-Uk Limited | Manufacturing | 2016 |
| MC Scaffolding EA Ltd | Construction | 2024 |
| MDC Trading Ltd | Professional & scientific | 2025 |
| Mdkb Ltd | Wholesale & retail | 2022 |
| Meadows Edge Lodgings Ltd | Hospitality | 2026 |
| Meda Autos Ltd | Wholesale & retail | 2022 |
| Melhado-Stannard Ltd | Arts & recreation | 2013 |
| Merton Farming Company Limited | Agriculture & fishing | 1974 |
| Metal Samples Supplies Limited | Extraterritorial | 1998 |
| Metropolitan Consulting Ltd | Professional & scientific | 2024 |
| MFJ Livestock Ltd | Agriculture & fishing | 2021 |
| MHR Logistics Ltd | Transport & logistics | 2019 |
| Michael Elliott Plumbing Ltd | Construction | 2014 |
| Michele's Home Help Limited | Other services | 2019 |
| Micro-Suction by Sadie Ltd | Wholesale & retail | 2022 |
| MID Norfolk GAS Ltd | Wholesale & retail | 2018 |
| Mikailian Group Limited | Extraterritorial | 2015 |
| Mike REA Consulting Limited | Professional & scientific | 2026 |
| Mike Robertson Ltd | Health & social care | 2013 |
| Milespholdings Ltd | Real estate | 2021 |
| Mimi's Cupcakes Limited | Wholesale & retail | 2023 |
| Mimram Business Services Limited | Real estate | 2004 |
| Mindsci Ltd | Health & social care | 2023 |
| Mini Market 2023 Ltd | Wholesale & retail | 2023 |
| Mirage Shows and Productions Limited | Arts & recreation | 2001 |
| Miro Drylining Ltd | Construction | 2024 |
| Mission Systems PTY Ltd | Professional & scientific | 2025 |
| Mithira Consultancy Ltd | Professional & scientific | 2024 |
| Mithira Ltd | Wholesale & retail | 2024 |
| MIZ Retail Ltd | Wholesale & retail | 2025 |
| Mizgin Cleaning Ltd | Administrative & support | 2021 |
| MJ Property Thetford Ltd | Real estate | 2020 |
| MLK Gold Property Limited | Real estate | 2025 |
| Mlodziezownia.Pl Ltd | Education | 2026 |
| Molly Garioch Ltd | Education | 2025 |
| Moorethan Group Ltd | Wholesale & retail | 2023 |
| Mortgage Chain Limited | Financial services | 2016 |
| Mortgage Ready Limited | Financial services | 2019 |
| Moto Wivegroup Ltd | Wholesale & retail | 2025 |
| Motonova Ltd | Wholesale & retail | 2012 |
| Mousa Electrical Limited | Real estate | 2018 |
| Mousa Electrical Services Limited | Construction | 2025 |
| Movesafe Property Management Limited | Professional & scientific | 1986 |
| MR Barbers Thetford Limited | Other services | 2021 |
| MRS Beans Limited | Hospitality | 2018 |
| MS 68 Limited | Construction | 2020 |
| Ms&W Property Ltd | Real estate | 2020 |
| MSH Cars UK Ltd | Wholesale & retail | 2024 |
| MSH Robinson Ltd | Wholesale & retail | 2019 |
| Multisigns Holdings Ltd | Financial services | 2024 |
| Multisigns Limited | Professional & scientific | 2002 |
| Munditia Ltd | Administrative & support | 2019 |
| Munford & Co Developments Ltd | Construction | 2023 |
| Munford & Sons Group Ltd | Financial services | 2023 |
| Munsters HMC (UK) Limited | Professional & scientific | 1983 |
| MWM (Anglia) Ltd | Construction | 2017 |
| My Golf Supplies Ltd | Wholesale & retail | 2025 |
| My Serviced Apartments Ltd | Hospitality | 2019 |
| MYH Services Ltd | Administrative & support | 2018 |
| MYI22 Ltd | Transport & logistics | 2024 |
| N & K 4X4 Ltd | Wholesale & retail | 2014 |
| N & N Projects Ltd | Construction | 2002 |
| N & N Signature Properties Limited | Real estate | 2021 |
| N Chamberlain Electrical Limited | Construction | 2015 |
| N&G Locksmiths Service Ltd | Administrative & support | 2025 |
| N. D. Richards Property Ltd | Real estate | 2022 |
| N.E Bookkeeping and Accounting Limited | Professional & scientific | 2023 |
| Nabir Cash & Carry Ltd | Wholesale & retail | 2021 |
| Narrative Fabrik Limited | Professional & scientific | 2015 |
| National Recycling Solutions Ltd | Other services | 2016 |
| Naturediet Holdings Limited | Financial services | 2015 |
| Naturediet Pet Foods Limited | Manufacturing | 1987 |
| Natures Sports and Outdoors Limited | Wholesale & retail | 2017 |
| Navitrum Ltd | Construction | 2022 |
| NB Accountancy Solutions Ltd | Professional & scientific | 2014 |
| ND Fire Safety Ltd | Professional & scientific | 2016 |
| Neaton Group Ltd | Construction | 2023 |
| Nehirsu Ltd | Hospitality | 2018 |
| Neil Cooper Electrical Services Ltd | Construction | 2022 |
| Nelsforge Enterprises Ltd | Wholesale & retail | 2023 |
| New Court Management Company (Brandon) Limited | Administrative & support | 1997 |
| Newbuild Frames Limited | Construction | 1971 |
| Newbuild Frames Trustees Limited | Administrative & support | 2024 |
| Newrooms (Methwold) Limited | Construction | 2011 |
| Nice & Tidy (UK) Limited | Other services | 2011 |
| Niku Ltd | Construction | 2023 |
| Nilokheri Fresh Produce Ltd | Wholesale & retail | 2026 |
| Nixon Control Services Limited | Professional & scientific | 2019 |
| Nkmk Ltd | Transport & logistics | 2023 |
| NKS Training Solutions Ltd. | Other services | 2013 |
| NLR Mortgages Limited | Financial services | 2022 |
| NMH Consultancy Limited | Information & communication | 2023 |
| NNN Electronics Ltd | Professional & scientific | 2021 |