| Millz Accountancy Services Ltd | Professional & scientific | 2019 |
| Ming House Ltd | Hospitality | 2015 |
| Miniscatter Limited | Real estate | 1988 |
| Minns Electrical Services Ltd | Construction | 2025 |
| Minter Holdings Limited | Financial services | 2024 |
| Minuteman Press (Kings Lynn) Limited | Manufacturing | 2004 |
| Mirror Mirror Boutique Salon Limited | Other services | 2015 |
| Misadventures Limited | Hospitality | 2019 |
| Misc Events Ltd | Arts & recreation | 2024 |
| Miss ICT Ltd | Information & communication | 2026 |
| Mitchelmark Investments Limited | Professional & scientific | 1963 |
| MJ Properties (Norfolk) Limited | Real estate | 2019 |
| MJB Bespoke Accountancy Ltd | Professional & scientific | 2025 |
| MJC Mortgages Limited | Financial services | 2026 |
| Mjrr Limited | Administrative & support | 2023 |
| MJS Install Limited | Construction | 2024 |
| MK Architects Limited | Professional & scientific | 2023 |
| MK7 Norfolk Limited | Manufacturing | 2021 |
| Mljbookkeeping Limited | Professional & scientific | 2012 |
| MLS Driver Hire Limited | Transport & logistics | 2012 |
| MM CN Limited | Other services | 2026 |
| MMI Trainer Ltd | Information & communication | 2025 |
| Mniek Trans Ltd | Transport & logistics | 2018 |
| Mnis Limited | Information & communication | 2003 |
| Mnsa Consultancy Ltd | Professional & scientific | 2017 |
| MNV Logistics Ltd | Transport & logistics | 2017 |
| MO Properties Limited | Real estate | 2018 |
| MOA Properties Ltd | Real estate | 2018 |
| Moat House Media Limited | Wholesale & retail | 2011 |
| Mobile Arena Limited | Information & communication | 1995 |
| Mobile Communication Specialists Limited | Information & communication | 1999 |
| Mobile Guru (INT) Ltd | Wholesale & retail | 2019 |
| Moda Photography Limited | Information & communication | 2019 |
| Modaro Developments Ltd | Manufacturing | 2025 |
| Modbay Roofing Ltd | Construction | 2025 |
| Mode Construction Ltd | Construction | 2015 |
| Mode Traders Limited | Construction | 2025 |
| Modernwall Ltd | Manufacturing | 2022 |
| Mojo & Mojo Limited | Agriculture & fishing | 2021 |
| Mole END Holdings Ltd | Real estate | 2024 |
| Momo Property Rentals Ltd | Real estate | 2025 |
| Mono Equipment Limited | Professional & scientific | 1954 |
| Monticule Ltd | Real estate | 2019 |
| Moore's Groundworks & Landscaping Services Limited | Administrative & support | 2024 |
| Moorelec Electrical Contractors Limited | Construction | 2018 |
| More & Moore Cash Limited | Administrative & support | 2004 |
| More Services (Lincs) Ltd | Construction | 2022 |
| Morgan Pettefar Limited | Administrative & support | 2022 |
| Morgan Trusts and Tax Planning Limited | Professional & scientific | 2016 |
| Morris & Daughters Property Ltd | Construction | 2023 |
| Mortgage Synergy Limited | Financial services | 2023 |
| Mortons Classic Cars Limited | Manufacturing | 2022 |
| Morvern Limited | Extraterritorial | 2006 |
| Mosaic Project Management Services Limited | Professional & scientific | 2009 |
| Most Wanted Wheels Limited | Manufacturing | 2026 |
| MOTIV8 Exercise and Fitness Limited | Arts & recreation | 2013 |
| Motivation and Rewards Limited | Wholesale & retail | 2019 |
| Moto LTU Ltd | Transport & logistics | 2017 |
| Moto-Mech Vehicle Services Ltd | Wholesale & retail | 2023 |
| Motorcycle Turntables Limited | Manufacturing | 2021 |
| Motorwerke Ltd | Wholesale & retail | 2021 |
| Mount Amelia Arts Ltd | Arts & recreation | 2012 |
| Mousetrading Ltd | Wholesale & retail | 2024 |
| MR Snippers Limited | Other services | 2005 |
| MR Wells Ltd | Information & communication | 2025 |
| MR. Signs Limited | Other services | 2000 |
| MRE Automotive Ltd | Wholesale & retail | 2023 |
| MSD Consultancy Services Limited | Professional & scientific | 2021 |
| MT Tyres Ltd | Wholesale & retail | 2021 |
| MTS Electrical Services Limited | Construction | 2015 |
| MU Data Systems Ltd | Information & communication | 2026 |
| Mulberry Court 15-18 RTM Company Limited | Real estate | 2012 |
| Muleterry Services Limited | Health & social care | 2023 |
| Mulready Associates Limited | Professional & scientific | 2003 |
| Multiplicand Limited | Financial services | 2021 |
| Munchkin and ME Ltd | Education | 2024 |
| Munehisa Homma Limited | Wholesale & retail | 2015 |
| Murkis Ltd | Transport & logistics | 2020 |
| Murtaja 4 Services Limited | Construction | 2025 |
| Musketeer Event Management Ltd. | Arts & recreation | 1999 |
| MV Decors Construction Limited | Construction | 2024 |
| Mvdeviseholdings Ltd | Construction | 2026 |
| Mvwn Ltd | Wholesale & retail | 2024 |
| MW Auto Revive Ltd | Wholesale & retail | 2026 |
| MWB Management Consulting Ltd | Professional & scientific | 2017 |
| MXN Sports Mgmt Limited | Professional & scientific | 2022 |
| Mybus Ltd | Transport & logistics | 2022 |
| Myna L2 Ltd | Professional & scientific | 2024 |
| Myne.Io Ltd | Information & communication | 2019 |
| Myrus Ltd | Professional & scientific | 2013 |
| N & L Martin Limited | Wholesale & retail | 2001 |
| N a Daly (Norwich) Limited | Extraterritorial | 2008 |
| N G Owen Roofing Ltd | Construction | 2012 |
| N K Bateman Main Laying & Plant Hire Ltd | Construction | 2024 |
| N&S Windows and Doors Ltd | Wholesale & retail | 2025 |
| N.H. Howard & SON Limited | Wholesale & retail | 1964 |
| N.I.M. Plumbing & Heating Limited | Construction | 2011 |
| N.K.Patrick Electrical Ltd | Manufacturing | 2017 |
| Naconia Limited | Financial services | 2021 |
| Nadin Hurley Ltd | Other services | 2015 |