| MAY Holdings (Essex) Limited | Real estate | 2023 |
| MC Trans Solution Ltd | Transport & logistics | 2019 |
| MCC Major Ltd | Transport & logistics | 2017 |
| Mcdworks CIC | Other services | 2022 |
| Mckings Int'L Integrated Services Ltd | Wholesale & retail | 2016 |
| Mdiamondaesthetics Ltd | Wholesale & retail | 2026 |
| Mede Transport Solutions Ltd | Transport & logistics | 2019 |
| Medelis Ltd | Construction | 2016 |
| Medical Administration Services Limited | Administrative & support | 2013 |
| Medico Gama Ltd | Manufacturing | 2024 |
| Meeks Global Ltd | Information & communication | 2025 |
| Meens Fruit and VEG Ltd | Wholesale & retail | 2026 |
| Meen’S UK Exports Ltd | Wholesale & retail | 2025 |
| Meen’S UK Ltd | Wholesale & retail | 2020 |
| Mega Boilers Ltd | Construction | 2021 |
| Mega Tiling UK Ltd | Construction | 2022 |
| Melsi Investments Limited | Wholesale & retail | 2021 |
| Meneghelo Ltd | Transport & logistics | 2018 |
| Mercy & Grace Real Estate Ltd | Real estate | 2026 |
| Mercycrest Investment Limited | Real estate | 2023 |
| Merlene UK Ltd | Health & social care | 2020 |
| Meta Business Services Ltd | Other services | 2014 |
| Meveme Moveon Limited | Health & social care | 2013 |
| Mezzie Youth FC Ltd | Education | 2022 |
| MGV Pro Limited | Real estate | 2025 |
| MGV Services Ltd | Construction | 2018 |
| MI Parcel UK Ltd | Transport & logistics | 2020 |
| Michael Bourkadi Limited | Information & communication | 2018 |
| Michaeldan Ltd | Transport & logistics | 2019 |
| Mihai Tanasescu Ltd | Administrative & support | 2019 |
| MIJ Consulting Limited | Financial services | 2015 |
| Mijeme TM Ltd | Construction | 2025 |
| Mike Apple Ltd | Wholesale & retail | 2013 |
| Milewise Logistics Limited | Transport & logistics | 2025 |
| Mili Media Limited | Information & communication | 2017 |
| Millennium Place Freeholders Limited | Households | 2023 |
| Ming Long 888 Limited | Hospitality | 2025 |
| Minted Oak Limited | Wholesale & retail | 2022 |
| Mipeco Ltd | Wholesale & retail | 2023 |
| Miro Contruction Ltd | Construction | 2021 |
| Misadep Properties Limited | Real estate | 2021 |
| Mislani Ltd | Wholesale & retail | 2019 |
| Miss Offline Ltd | Wholesale & retail | 2026 |
| Misterton Medical Services Limited | Wholesale & retail | 2007 |
| MIX IT UP Cocktails Ltd | Hospitality | 2023 |
| MJ Essex Autos Ltd | Wholesale & retail | 2016 |
| MLM Solution Ltd | Construction | 2013 |
| Mmod Services Ltd | Construction | 2025 |
| MMS Cars Ltd | Transport & logistics | 2024 |
| MN Base Ltd | Construction | 2024 |
| MN Fitting Limited | Construction | 2026 |
| MNA Business Services Ltd | Professional & scientific | 2006 |
| MO BRO Homes Ltd | Real estate | 2024 |
| Mochaa Ltd | Construction | 2016 |
| Mochnal Limited | Health & social care | 2014 |
| MODCRE81T.CO.UK Ltd | Construction | 2023 |
| Modern Structures London Ltd | Construction | 2020 |
| Modessa UK Limited | Wholesale & retail | 2025 |
| MOE Group Ltd | Education | 2023 |
| Mogsam Properties Ltd | Real estate | 2022 |
| Moises Services Ltd | Transport & logistics | 2016 |
| Momentum Focus Ltd | Wholesale & retail | 2026 |
| Monarch Contractors Ltd | Construction | 2020 |
| Mona’S Exclusives Ltd | Hospitality | 2025 |
| Moreish Desserts Limited | Manufacturing | 2025 |
| Motion Motors Ltd | Wholesale & retail | 2026 |
| Motorland MOT Ltd | Wholesale & retail | 2019 |
| Mounton Ltd | Construction | 2026 |
| MP Prestige Limited | Administrative & support | 2025 |
| MPX Hub (Lytham) Limited | Wholesale & retail | 2009 |
| MR. Marketing Limited | Administrative & support | 2011 |
| MSK Interiors and Design Ltd | Construction | 2019 |
| Msms Essex Limited | Hospitality | 2021 |
| MVB Services Limited | Construction | 2024 |
| MVV Cars Ltd | Transport & logistics | 2024 |
| My Ideal Mortgage Limited | Financial services | 2014 |
| My Ideal Property Partners Ltd | Real estate | 2024 |
| My Space Solutions Limited | Education | 2014 |
| My World of Gifts Ltd | Wholesale & retail | 2020 |
| Mysa Pilates Studio Ltd | Arts & recreation | 2025 |
| MYSTICAL3D Ltd | Manufacturing | 2025 |
| Mytherapycare Limited | Health & social care | 2021 |
| N&G Building Solutions Ltd | Construction | 2012 |
| N.K Specialists Ltd | Other services | 2022 |
| Nad-Nat Ltd | Transport & logistics | 2017 |
| Najm Management Limited | Construction | 2020 |
| Nakara Services | Education | 2019 |
| Nald Development Limited | Construction | 2013 |
| Nanny 1WORK Ltd | Health & social care | 2022 |
| Nanu Performance Ltd | Construction | 2019 |
| Nanuia Limited | Construction | 2023 |
| Nastasi Consulting Ltd | Professional & scientific | 2026 |
| Navsamajdarpan | Health & social care | 2019 |
| Naya-Ai Ltd | Wholesale & retail | 2025 |
| NBJ Auto Group Ltd | Wholesale & retail | 2024 |
| ND Property Solutions Ltd | Construction | 2026 |
| NDA Heating Plumbing and Air Condition Ltd | Construction | 2025 |
| Nellia Private Limited | Health & social care | 2015 |
| NET Axis Wholesale UK Ltd | Information & communication | 2024 |
| Netbak Limited | Professional & scientific | 2010 |