| Modern Nature Productions Limited | Information & communication | 2021 |
| Modern Press (Norwich) Limited, | Manufacturing | 1953 |
| Modewear Ltd | Wholesale & retail | 2025 |
| Modo Pilates Ltd | Arts & recreation | 2026 |
| Modular (EA) Ltd | Construction | 2013 |
| Modular Grow Systems Ltd | Construction | 2020 |
| Modular Room Solutions Ltd | Construction | 2019 |
| Modus Property Holdings Limited | Real estate | 2023 |
| Mofl Transition Limited | Wholesale & retail | 1992 |
| Mohajon Ltd | Hospitality | 2019 |
| Mohsin Constructions Ltd | Construction | 2016 |
| Mohxin Tradings Ltd | Wholesale & retail | 2023 |
| MOI Thai Foods Ltd | Hospitality | 2026 |
| Moirce Ltd | Wholesale & retail | 2022 |
| Moire Ventures Ltd | Professional & scientific | 2018 |
| Mojito Cartel Ltd | Wholesale & retail | 2020 |
| Mojo Assets Ltd | Administrative & support | 2016 |
| Mojo Media Norfolk Limited | Professional & scientific | 2010 |
| Moka Coffee House Ltd | Hospitality | 2026 |
| Mokhothu Limited | Health & social care | 2013 |
| Mollo Interiors Ltd | Construction | 2006 |
| Molly-Jo Mortgages Ltd | Financial services | 2019 |
| Molly-Jo Properties Ltd | Real estate | 2021 |
| Mollycoddle Studios Ltd | Wholesale & retail | 2026 |
| Molten Music Technology Limited | Information & communication | 2013 |
| Molto (Norwich) Ltd | Hospitality | 2013 |
| Moments Notice Ltd | Extraterritorial | 2021 |
| Momentum One Ltd | Professional & scientific | 2025 |
| MON Chai Limited | Hospitality | 2022 |
| MON Experience Limited | Hospitality | 2024 |
| Mona Anaesthesia Services Ltd | Health & social care | 2016 |
| Monach Management Ltd | Manufacturing | 2013 |
| Monarc Welding Limited | Manufacturing | 2016 |
| Monarch Hygiene Limited | Water & waste | 2026 |
| Monarch Signs Limited | Manufacturing | 2001 |
| Monday Matters Recruitment Ltd | Administrative & support | 2023 |
| Mondrian Consultancy Limited | Information & communication | 2014 |
| Moneyfacts Group PLC | Administrative & support | 2000 |
| Moneyfacts.Co.Uk Limited | Information & communication | 2008 |
| Monica Care Services Ltd | Health & social care | 2015 |
| Monique Jones PT Ltd | Other services | 2023 |
| Monitor My IOT Limited | Manufacturing | 2025 |
| Monk Plant Hire Limited | Construction | 2003 |
| Monk Premier Homes Limited | Real estate | 2021 |
| Monk Property Holdings Limited | Real estate | 2021 |
| Monkey Smiles Property Ltd | Real estate | 2024 |
| Monkey's Uncle Limited | Information & communication | 2003 |
| Mono House Ltd | Real estate | 2022 |
| Monopoly Deal Housing Ltd | Real estate | 2025 |
| Monsey Property Group Ltd | Real estate | 2024 |
| Montazer Properties Ltd | Real estate | 2024 |
| Monteith Macfarlane Limited | Wholesale & retail | 2017 |
| Montenegro Erin Ltd | Health & social care | 2019 |
| Montessori Pre-School Limited | Other services | 2007 |
| Montizuma Ltd | Manufacturing | 2020 |
| Montpellier House Capital Limited | Financial services | 2025 |
| Monty Holdings Ltd | Financial services | 2024 |
| Monty's Gardening Services Ltd | Administrative & support | 2024 |
| Monument Trading Ltd | Real estate | 2017 |
| MOO & ME Limited | Wholesale & retail | 2026 |
| Moobip Digital Ltd | Information & communication | 2019 |
| Moodment Retreats Ltd | Hospitality | 2025 |
| Mookaroo Limited | Real estate | 2019 |
| Moolahs Convenience Store Ltd | Wholesale & retail | 2020 |
| Moon 22 Ltd | Hospitality | 2022 |
| Moon Electrical and Home Improvements Limited | Other services | 2018 |
| Moon on a Stick Theatre Company Ltd | Arts & recreation | 2015 |
| Moon PIE Properties Ltd | Real estate | 2022 |
| Moon Rocket Games Limited | Information & communication | 2014 |
| Moonlab Ventures Ltd | Financial services | 2025 |
| Moonraker Motorcycles Limited | Wholesale & retail | 2003 |
| Moonrise INK Ltd | Arts & recreation | 2025 |
| Moonrock Gems Ltd | Wholesale & retail | 2025 |
| Moonveil Limited | Financial services | 2022 |
| Moonwell Ltd | Administrative & support | 2025 |
| Moore & Ford Surfacing Ltd | Professional & scientific | 2007 |
| Moore & Moore Living Limited | Health & social care | 2017 |
| Moore Adventure Ltd | Arts & recreation | 2013 |
| Moore Catering Limited | Hospitality | 2025 |
| Moore Components Ltd | Wholesale & retail | 2025 |
| Moore Engineering Services Ltd | Manufacturing | 2026 |
| Moore Fuller Consulting Ltd | Professional & scientific | 2018 |
| Moore Heating Services Ltd | Construction | 2022 |
| Moore Home Improvements Ltd | Construction | 2007 |
| Moore Networking Limited | Administrative & support | 2002 |
| Moore Numbers Limited | Professional & scientific | 2014 |
| Moore Style Property Limited | Real estate | 2017 |
| Mooreniven Ltd | Wholesale & retail | 2020 |
| Moorestyle Energy Limited | Energy | 2022 |
| Moorestyle Limited | Real estate | 2020 |
| Moosey Editions Ltd | Information & communication | 2024 |
| Morbit Software Ltd | Information & communication | 2020 |
| More Flour to the People Ltd | Hospitality | 2017 |
| More Restaurants Limited | Hospitality | 2011 |
| Morello Services Limited | Construction | 1979 |
| Moremor Ltd | Administrative & support | 2025 |
| Morgan & Co Ventures Limited | Financial services | 2021 |
| Morgan Blake Solutions Limited | Professional & scientific | 2009 |
| Morgan House RTM Company Limited | Households | 2022 |
| Morgan Jones & Pett Limited | Administrative & support | 2007 |