| MJV & Co. Limited | Professional & scientific | 1998 |
| MKB Roofing Services Ltd | Construction | 2026 |
| MLC Carpentry Ltd | Construction | 2014 |
| MLL Property Ltd | Construction | 2022 |
| MLT Support Consultancy Ltd | Information & communication | 2023 |
| MM Furniture Fitters Limited | Construction | 2026 |
| MMR Restaurant Limited | Hospitality | 2025 |
| MN Industries Limited | Wholesale & retail | 2026 |
| Mobile Home Transport Ltd | Transport & logistics | 2025 |
| MOD a Mini Ltd | Wholesale & retail | 2018 |
| Molizade Limited | Real estate | 2024 |
| Montpelier Court (Brentwood) Limited | Real estate | 1994 |
| Montrasystems Ltd | Professional & scientific | 2026 |
| Monzonite Limited | Administrative & support | 2018 |
| Moody Homes Holdings Limited | Financial services | 2026 |
| Moody Homes Limited | Construction | 1993 |
| Moore Marine and General Design Limited | Professional & scientific | 2026 |
| More Than Balls Limited | Wholesale & retail | 2003 |
| Morley Racing Ltd | Arts & recreation | 2016 |
| Morley Skips Ltd | Water & waste | 2006 |
| Morning Beautiful Ltd | Extraterritorial | 2021 |
| Mothers Ruin Bristol Limited | Hospitality | 2017 |
| Motion Events Group Ltd | Other services | 2025 |
| Motor Rentals Ltd | Administrative & support | 2024 |
| Motor Vehicles Stolen Limited | Information & communication | 2017 |
| Mova Jewellery Limited | Manufacturing | 2015 |
| Movannar Holdings Limited | Financial services | 2025 |
| MPD Projects Ltd | Construction | 2018 |
| MR Churros (London) Ltd | Hospitality | 2024 |
| MR Wheeler Limited | Agriculture & fishing | 2014 |
| Mras Services Limited | Professional & scientific | 2023 |
| Mrim Properties Ltd | Real estate | 2025 |
| MRN Training Limited | Administrative & support | 2016 |
| MRW Property Services Ltd | Real estate | 2023 |
| MS Bricklaying Services Limited | Construction | 2015 |
| MSI Entertainment Ltd | Arts & recreation | 2026 |
| Munchkins Day Care (Baddow) Limited | Health & social care | 2023 |
| Munchkins Day Care (Brentwood) Limited | Health & social care | 2024 |
| Munchkins Day Care (Dunton Park) Limited | Health & social care | 2022 |
| Munchkins Day Care (Laindon) Limited | Health & social care | 2018 |
| Munchkins Daycare (Billericay) Limited | Health & social care | 2025 |
| Munchkins Daycare (Brightlingsea) Limited | Health & social care | 2020 |
| Munchkins Daycare (Dunton Fields) Limited | Health & social care | 2019 |
| Munchkins Holdings Limited | Financial services | 2023 |
| Murfy Holdings Limited | Financial services | 2020 |
| Muse DE SOI Ltd | Wholesale & retail | 2026 |
| Music Theatre Essex Ltd | Arts & recreation | 2022 |
| Mustard Mortgages Limited | Financial services | 2020 |
| Muted Healing Ltd. | Health & social care | 2022 |
| MVD Property Limited | Construction | 2025 |
| MVS 2002 Limited | Wholesale & retail | 2007 |
| MW Flooring Limited | Construction | 2021 |
| My CTO Ltd | Information & communication | 2020 |
| My First Organics Ltd | Manufacturing | 2023 |
| My Perfect Giftbox Limited | Wholesale & retail | 2013 |
| My Pool Direct Limited | Wholesale & retail | 2025 |
| Mycastle Next Ltd | Administrative & support | 2025 |
| Mychem Limited | Wholesale & retail | 2006 |
| Myeducate Limited | Education | 2025 |
| Myjoule Energy Ltd | Construction | 2020 |
| Mynutrition (GC) Ltd | Health & social care | 2019 |
| N & W Services Limited | Construction | 2007 |
| N&E Maldon Car Wash Ltd | Other services | 2024 |
| N.O.V8 Consulting Limited | Professional & scientific | 2017 |
| N.O.Y.B. Productions Ltd | Arts & recreation | 2023 |
| N.W. Carpentry Ltd | Manufacturing | 2018 |
| NA Group Holdings Limited | Financial services | 2024 |
| NA Property Holdings Limited | Financial services | 2024 |
| NA Service Stations Limited | Wholesale & retail | 2024 |
| NAK Access Solutions Limited | Administrative & support | 2021 |
| Nandra Investments Limited | Financial services | 2025 |
| Nanosoft Corporation Limited | Wholesale & retail | 2008 |
| Nash House Management Company Limited | Households | 1983 |
| Nass Services Limited | Manufacturing | 2009 |
| Nassboards Limited | Professional & scientific | 2016 |
| National Holdings Ltd | Professional & scientific | 2019 |
| Natural Print Solutions Ltd | Manufacturing | 2010 |
| Natwest House Property Limited | Real estate | 2016 |
| Nautonomy Limited | Manufacturing | 2024 |
| NBC Electricals Ltd | Construction | 2022 |
| NC Appliance Repairs Limited | Other services | 2013 |
| NCS Marine Ltd | Construction | 1984 |
| Ndmw Limited | Administrative & support | 2026 |
| Necton Developments Ltd | Construction | 2023 |
| Needaknowa Limited | Information & communication | 2016 |
| Neil’S on Wheels Limited | Education | 2024 |
| Nelson & Mace Limited | Real estate | 2021 |
| Nemesis Corporation LLP | | 2011 |
| NEO Argo Limited | Professional & scientific | 2009 |
| Neophoenix Ltd | Other services | 2022 |
| Neptoon Limited | Administrative & support | 2016 |
| Netcast Consulting Limited | Administrative & support | 2010 |
| Netshack Online Ltd | Wholesale & retail | 2014 |
| Neuro Focus Therapy Ltd | Health & social care | 2024 |
| New Farm Stud Limited | Agriculture & fishing | 2025 |
| New Inn 2019 Ltd | Hospitality | 2019 |
| Newell & Allen Limited | Construction | 2015 |
| Newland Building Contracts Limited | Construction | 2025 |
| Newland Land Holdings Limited | Construction | 2019 |
| Newlands Services Ltd | Professional & scientific | 2024 |