| Lottie Louise Designs Ltd | Wholesale & retail | 2019 |
| Louise & James Property Management Limited | Households | 2025 |
| Love Your Feet Ltd. | Health & social care | 2013 |
| LR91 Performance Coaching Ltd | Other services | 2024 |
| Lucian F Limited | Transport & logistics | 2016 |
| Luke Stevens Electrical Limited | Construction | 2018 |
| Luna House Events Ltd | Administrative & support | 2026 |
| LUP Spedition Ltd | Transport & logistics | 2025 |
| Luxelivingfinds UK Ltd | Wholesale & retail | 2025 |
| LWFIRSTAID4ALL Limited | Health & social care | 2025 |
| Lybreeze Software Limited | Information & communication | 2002 |
| M & P PUB Group Ltd | Hospitality | 2026 |
| M & T Memorabilia Ltd | Wholesale & retail | 2026 |
| M and T Mahoney Limited | Other services | 2002 |
| M J Stores London Ltd | Wholesale & retail | 2025 |
| M J Wright Limited | Professional & scientific | 2013 |
| M P Trading Limited | Wholesale & retail | 2009 |
| M R L Productions (UK) Limited | Information & communication | 2007 |
| M.L.G.T Building Services Limited | Construction | 2025 |
| Mactoushe Enterprise Limited | Wholesale & retail | 2024 |
| MAD Hatters Cafe (Essex) Ltd | Hospitality | 2020 |
| MAF Cars Limited | Transport & logistics | 2007 |
| Magical Promotions Ltd | Arts & recreation | 2021 |
| Magna Party Wall Limited | Professional & scientific | 2024 |
| Magna Surveying Limited | Professional & scientific | 2023 |
| Mahins Enterprise Limited | Administrative & support | 2018 |
| Mama J'S Cuisine Ltd | Hospitality | 2021 |
| Mama's Fruit & VEG Ltd | Wholesale & retail | 2025 |
| Mannix Trading Limited | Administrative & support | 2016 |
| Manor Way (Holland-On-Sea) Management Company Limited | Households | 1991 |
| Manson & Sullivan Property Group Ltd | Real estate | 2026 |
| Marawes Ltd | Wholesale & retail | 2015 |
| Marctina Group Ltd | Professional & scientific | 2018 |
| Margin Hour Ltd | Professional & scientific | 2024 |
| Marine & Agricultural Clothing Ltd | Wholesale & retail | 2010 |
| Marine & Industrial Diesel Applied Services Limited | Professional & scientific | 2011 |
| Marine Inn Ltd | Hospitality | 2026 |
| Mario STE Service Limited | Wholesale & retail | 2025 |
| Mark Jones Groundworks Limited | Construction | 2014 |
| Mark Reynolds Plumbing & Heating Services Limited | Other services | 2000 |
| Marketme.Tv Limited | Information & communication | 2010 |
| Marney Rail Limited | Construction | 2018 |
| Martello Steel Ltd | Construction | 2022 |
| Martynross Ltd | Wholesale & retail | 2021 |
| Maru Spice Ltd | Hospitality | 2022 |
| Mary and Martha Limited | Real estate | 2026 |
| Maserowebsolutions Ltd | Information & communication | 2026 |
| Mason Country Lets Ltd | Real estate | 2025 |
| Mass Solar UK Ltd | Construction | 2025 |
| Masterson Leisure Limited | Arts & recreation | 2005 |
| Matriax Ltd | Information & communication | 2025 |
| Matrix Property Limited | Construction | 2015 |
| Mattress MAN of Essex Ltd | Wholesale & retail | 2016 |
| MAVMAVA1 Ltd | Real estate | 2026 |
| Mayside Limited | Information & communication | 2017 |
| MC Rail Solutions Ltd | Professional & scientific | 2016 |
| Mcevoy Consultancy Solutions Limited | Professional & scientific | 2011 |
| MD Jaywick Properties Ltd | Real estate | 2021 |
| MD Rentals Ltd | Real estate | 2025 |
| MD Setting OUT and Surveys Ltd | Construction | 2022 |
| MDC Music Limited | Information & communication | 2025 |
| MDW Property Group Limited | Real estate | 2024 |
| Medical Hoist Installations Ltd | Construction | 2023 |
| Meecham Motorworks Ltd | Wholesale & retail | 2025 |
| Mephalti Ltd | Information & communication | 2023 |
| Mephit Ltd | Transport & logistics | 2025 |
| Mersea Island Tanning Bar Ltd | Other services | 2018 |
| Meta Clad Glaze Limited | Construction | 2025 |
| Metcalfe Driving Services Ltd | Transport & logistics | 2019 |
| Mettanurse Ltd | Administrative & support | 2023 |
| MID Essex Historic Buildings Trust | Arts & recreation | 1998 |
| Migs Tints Ltd | Wholesale & retail | 2023 |
| MIL Construction Ltd | Construction | 2023 |
| Milestone Moments Events Limited | Hospitality | 2025 |
| Mileybow Fabrics and Trimmings Limited | Wholesale & retail | 2016 |
| Mill Building Developers Ltd | Construction | 2021 |
| Mini Euro Clacton Ltd | Wholesale & retail | 2025 |
| Mirabeau Consulting Ltd | Professional & scientific | 2025 |
| Miste Courier Services Limited | Transport & logistics | 2013 |
| Miste Ltd | Wholesale & retail | 2012 |
| MJ Brickwork Ltd | Construction | 2024 |
| Mjcw Property Ltd | Real estate | 2026 |
| Mjjf Properties Ltd | Real estate | 2025 |
| Mkaf Holdings Limited | Financial services | 2020 |
| MKS Developments Limited | Manufacturing | 2013 |
| MNB PAT Testing Ltd | Other services | 2018 |
| Modasher Limited | Wholesale & retail | 2023 |
| Modsurplus Limited | Wholesale & retail | 2014 |
| Mohamrail Limited | Construction | 2018 |
| Monad Gottfried Ltd | Professional & scientific | 2019 |
| Monty's Equestrian Centre Ltd | Education | 2017 |
| Mookies Miniatures Limited | Wholesale & retail | 2017 |
| Moores Flooring Ltd | Construction | 2023 |
| Moos Property Investment Ltd | Real estate | 2021 |
| Morbow Limited | Other services | 2023 |
| Moringa International Group Ltd | Agriculture & fishing | 2023 |
| Mortgage Central Ltd | Financial services | 2007 |
| Mortlake Electrical Contractors Limited | Construction | 2008 |
| Mossy Engineering Ltd | Construction | 2017 |
| MOT Quality Management Ltd | Wholesale & retail | 2017 |