| Muka Property Services Limited | Real estate | 2024 |
| Mukesh Kumar Bharti Ltd | Construction | 2026 |
| Mulgys Engineering Limited | Professional & scientific | 2019 |
| Muls Consultancy Ltd | Professional & scientific | 2026 |
| Multani Properties London Limited | Real estate | 2022 |
| Multi Dimensional Traders Ltd | Wholesale & retail | 2018 |
| Multimercial Glass Ltd | Professional & scientific | 2026 |
| Multiple Streams CH Limited | Real estate | 2017 |
| Multiple Streams Holdings Ltd | Financial services | 2022 |
| Mum’S Pride Daycare Limited | Health & social care | 2019 |
| Munday to Sunday Ltd | Construction | 2021 |
| Munday Worx Ltd | Information & communication | 2025 |
| Munde Ltd | Information & communication | 2023 |
| Munez Limited | Wholesale & retail | 2020 |
| Murphy & Kirkland Ltd | Financial services | 2023 |
| Murphy's Carpentry Ltd | Construction | 2025 |
| Murryhill Holdings Limited | Real estate | 1986 |
| Musica Cruise Limited | Transport & logistics | 2020 |
| Musicjam Ltd | Information & communication | 2010 |
| Muslim Market Ltd | Financial services | 2025 |
| Musthaveit Ltd | Wholesale & retail | 2026 |
| Mutemo Business Ltd | Administrative & support | 2025 |
| Muthike-Job Limited | Health & social care | 2016 |
| Muthu Capitals Limited | Households | 2025 |
| Muzamal Zahoor Ltd | Manufacturing | 2026 |
| MV Biggleswade Ltd | Real estate | 2016 |
| Mvastu Limited | Professional & scientific | 2023 |
| MVD House Limited | Real estate | 2013 |
| Mvea Enterprise Ltd | Wholesale & retail | 2024 |
| My Carpet Gallery Ltd | Construction | 2024 |
| My Castle Limited | Real estate | 2017 |
| My Continental Food Store Limited | Wholesale & retail | 2025 |
| My Glazing Ltd | Construction | 2025 |
| My Global Ventures Limited | Extraterritorial | 2015 |
| My HMO Ltd | Real estate | 2023 |
| My Landlord Ltd | Real estate | 2026 |
| My Local Uxbridge Ltd | Hospitality | 2026 |
| My Rent Rewards Ltd | Extraterritorial | 2017 |
| My Repro Limited | Manufacturing | 2005 |
| My VET 24-7 Limited | Professional & scientific | 2009 |
| MYA Media Production Ltd. | Information & communication | 2014 |
| Myadlocal Cinema Ltd | Information & communication | 2026 |
| Myadlocal Ltd | Information & communication | 2024 |
| Mycare Home Services Ltd | Administrative & support | 2016 |
| Mydata-Compliance Ltd | Information & communication | 2023 |
| Mydata-T Ltd | Information & communication | 2020 |
| MYK DOS Auto Ltd | Other services | 2018 |
| Mystic Butterfly Limited | Extraterritorial | 2012 |
| Mystic Grill Limited | Hospitality | 2018 |
| MZB Removals Ltd | Transport & logistics | 2025 |
| Mzelectronics Ltd | Wholesale & retail | 2026 |
| MZM84 Limited | Transport & logistics | 2020 |
| N B Builders London Ltd | Construction | 2026 |
| N E Electrical (London) Limited | Construction | 2017 |
| N Misra Ltd | Health & social care | 2025 |
| N&E Design and Engineering Ltd | Construction | 2025 |
| N. & P. Thermoplastic Moulders (Whitton) Limited | Manufacturing | 1982 |
| N.S Accounting (UK) Limited | Professional & scientific | 2019 |
| Nabarro Accountants Limited | Professional & scientific | 2014 |
| Nabs DLH Ltd | Wholesale & retail | 2026 |
| Nadia and Sons Limited | Hospitality | 2004 |
| Nail Basics Limited | Professional & scientific | 1987 |
| Nail Paradise Limited | Other services | 2021 |
| Nails at Ruby's Limited | Other services | 2011 |
| Nails With DEE Ltd | Other services | 2023 |
| Najm Property Ltd | Real estate | 2025 |
| Nakayama Limited | Wholesale & retail | 2022 |
| Naked Shells Limited | Wholesale & retail | 2018 |
| Naleka Healthcare Limited | Health & social care | 2023 |
| Nalmere Ltd | Wholesale & retail | 2022 |
| Namakeen Mandi Foods ADA Limited | Hospitality | 2019 |
| NAN Development Ltd | Construction | 2025 |
| Nanababa Ltd | Wholesale & retail | 2022 |
| Nandal Holdings Ltd | Real estate | 2025 |
| Naqvi Trader Ltd | Wholesale & retail | 2021 |
| Narang and Sons Ltd | Wholesale & retail | 2026 |
| NAS Builders Limited | Construction | 2020 |
| Nasban Tech Solutions Ltd | Information & communication | 2025 |
| Nashville Uxbridge Ltd | Hospitality | 2026 |
| Nasri Property Limited | Real estate | 2021 |
| Nastra Limited | Wholesale & retail | 2021 |
| Natalie Marie Skincare Ltd | Wholesale & retail | 2022 |
| Nathan Price Ltd | Extraterritorial | 2023 |
| National Business Network Limited | Information & communication | 2005 |
| Nationwide Live in Care Ltd | Health & social care | 2022 |
| Nationwide Maintenance Limited | Professional & scientific | 2019 |
| Nature Clean & Co Ltd | Administrative & support | 2025 |
| Naturelle Limited | Professional & scientific | 1990 |
| Natzu Investments Limited | Financial services | 2026 |
| Naumaan Ltd | Hospitality | 2025 |
| Navansh Enterprises Private UK Limited | Transport & logistics | 2024 |
| Navid Building Services Ltd. | Administrative & support | 2020 |
| Navigating Growth Limited | Other services | 2025 |
| Navis Holding Group Ltd | Wholesale & retail | 2019 |
| Navriss Global Ltd | Professional & scientific | 2025 |
| Nawab&Sons.Szmo Ltd | Wholesale & retail | 2024 |
| NAZ Builders & Constructors Limited | Construction | 2024 |
| NB Urology Ltd | Health & social care | 2024 |
| Nbcmh Holdings Limited | Professional & scientific | 2014 |
| NBS Builders Ltd | Construction | 2020 |