| Mgid London Ltd | Professional & scientific | 2022 |
| MGM Constructions (London) Limited | Extraterritorial | 2012 |
| MHA Newbury Park Limited | Construction | 2023 |
| MHC Ecom Limited | Manufacturing | 2025 |
| Micost Contractors Ltd | Construction | 2025 |
| Micost Ltd | Transport & logistics | 2023 |
| MIG27 Limited | Transport & logistics | 2019 |
| Milana Joinery Ltd | Construction | 2019 |
| Millbrook (Chigwell) Management Company Limited | Households | 1988 |
| Millynik Limited | Health & social care | 2024 |
| MINAT247 Ltd | Administrative & support | 2026 |
| Mind Body Soul Studios Ltd | Arts & recreation | 2025 |
| Minecare Ltd | Health & social care | 2023 |
| Mini Nanny 2025 Ltd | Health & social care | 2025 |
| Mini Sibling Limited | Manufacturing | 2015 |
| MJA Rails Ltd | Construction | 2023 |
| MK Data Ltd | Information & communication | 2022 |
| MK London Property Management Ltd | Real estate | 2025 |
| MKM Construction Limited | Construction | 2013 |
| MKS Properties London Limited | Real estate | 2026 |
| MLD Consulting Ltd | Other services | 2019 |
| MM Flooring Limited | Construction | 2014 |
| Mmcs Construction Ltd | Construction | 2020 |
| Mmoja Ltd | Hospitality | 2026 |
| Mode London Ltd | Wholesale & retail | 2021 |
| Mode Photo Holdings Limited | Financial services | 2026 |
| Mode Photo Ltd | Professional & scientific | 2023 |
| Modern Property Investors Ltd | Real estate | 2021 |
| Mohindra a LLP | | 2026 |
| Mohindra Consulting Limited | Administrative & support | 2023 |
| Mohindra Limited | Professional & scientific | 2017 |
| Moin Constructions Ltd | Construction | 2026 |
| Molat Brothers Ltd | Transport & logistics | 2026 |
| Molo UK Construction Ltd | Construction | 2025 |
| Montpelier Construction and Development Limited | Construction | 2017 |
| Moonstar UK Ltd | Information & communication | 2025 |
| Morah Services Limited | Health & social care | 2016 |
| Mortgage Matters (London) Ltd. | Financial services | 2001 |
| Mortgage SOLUTION4U Ltd | Financial services | 2025 |
| Motif Inc Limited | Professional & scientific | 2024 |
| Motomot Ltd | Wholesale & retail | 2026 |
| Mouna.N.J Business Ltd | Professional & scientific | 2025 |
| Mount Solutions Limited | Wholesale & retail | 2026 |
| Move Ahead Limited | Construction | 2023 |
| Mozaicinteriors Ltd | Construction | 2026 |
| MP Civil & Structural Engineers Ltd | Professional & scientific | 2022 |
| MP Real Estate Ventures Ltd | Real estate | 2023 |
| MPD Express Ltd | Transport & logistics | 2015 |
| MR CAN Ltd | Administrative & support | 2016 |
| MRB Medical Ltd | Health & social care | 2015 |
| MRV1 Ltd | Construction | 2025 |
| MS Cleaning Ltd | Administrative & support | 2025 |
| MS OFF Licence Ltd | Wholesale & retail | 2024 |
| MSK Brothers Groceries Ltd | Wholesale & retail | 2026 |
| MSK Brothers Home Appliances Ltd | Wholesale & retail | 2026 |
| MSK Brothers Services Ltd | Professional & scientific | 2026 |
| MTC Ecom Ltd | Other services | 2025 |
| MTD Motors Ltd | Wholesale & retail | 2026 |
| MTE Services Ltd | Construction | 2016 |
| MTP Market Ltd | Wholesale & retail | 2026 |
| Mtrb Limited | Health & social care | 2018 |
| Mubaero Ltd | Manufacturing | 2024 |
| Mughalu Ltd | Transport & logistics | 2026 |
| Muldine Ltd | Construction | 2023 |
| Mulhalls Consultancy Ltd | Financial services | 2020 |
| Multistart Ltd | Construction | 2021 |
| Munchy's Limited | Other services | 2025 |
| Mutabadil TV Limited | Information & communication | 2022 |
| Mvm-Uk Limited | Real estate | 2015 |
| Mxmindset Limited | Information & communication | 2010 |
| My Bathroom Renovation Limited | Construction | 2021 |
| My Education Online Ltd | Education | 2020 |
| My First Steps Limited | Health & social care | 2024 |
| My N Business UK Ltd | Health & social care | 2024 |
| Myar Ltd | Real estate | 2023 |
| Myspace Services Limited | Real estate | 2022 |
| Myyatra Ltd | Health & social care | 2021 |
| Myzas Holdings Ltd | Real estate | 2019 |
| N & G Estates Ltd | Real estate | 2020 |
| N R C Property Ltd | Real estate | 2020 |
| N Starr Service Ltd | Administrative & support | 2021 |
| N&B World Ltd | Construction | 2019 |
| N1C Properties Ltd | Real estate | 2024 |
| Nadukkudiyil Ltd | Real estate | 2023 |
| Nagl Food Service Limited | Hospitality | 2024 |
| Nairlaw Ltd | Professional & scientific | 2024 |
| Nameco Properties Limited | Real estate | 2020 |
| Naothan Limited | Information & communication | 2018 |
| Narse Ltd | Other services | 2015 |
| Natlus Properties Limited | Households | 2012 |
| Natural Living Ltd | Wholesale & retail | 2026 |
| Natural Nubian Dolls Limited | Arts & recreation | 2016 |
| Needmoreprod Ltd | Information & communication | 2022 |
| Neemo Studio Ltd | Information & communication | 2024 |
| Nelm Investments Limited | Real estate | 2021 |
| Netminder Limited | Real estate | 2008 |
| Netsap Investment Limited | Real estate | 2023 |
| New Bird London Ltd | Wholesale & retail | 2024 |
| New Dream House Construction Ltd | Construction | 2026 |
| New Fried Foods Limited | Hospitality | 2021 |