| Municipal Chambers Resident Management Company Limited | Households | 2024 |
| Munster Consulting Limited | Professional & scientific | 2026 |
| Murban Ltd | Administrative & support | 2025 |
| Murdoch Properties (NW) Limited | Real estate | 2018 |
| Murphy's Law Group Ltd | Professional & scientific | 2024 |
| Muse Estates Ltd | Real estate | 2024 |
| Musket UK Holding Limited | Wholesale & retail | 2023 |
| Muslimi Limited | Professional & scientific | 2025 |
| Mustard Seed Estate & Letting Ltd | Real estate | 2024 |
| Mutale Engineering Strategies Limited | Professional & scientific | 2024 |
| MV Flooring Ltd | Construction | 2017 |
| MVC Fitness Ltd | Arts & recreation | 2025 |
| MVM Property Holdings Ltd | Real estate | 2025 |
| Mvpae Ltd | Wholesale & retail | 2026 |
| Mwellbeing Centre Ltd | Professional & scientific | 2025 |
| MWM Property Management Ltd | Households | 2023 |
| Mwqss Limited | Professional & scientific | 2026 |
| MXJ Properties Limited | Real estate | 2021 |
| My Bloods Limited | Health & social care | 2024 |
| My Blueprint Safe Store Limited | Financial services | 2010 |
| My Blueprint Wills & Estate Planning Ltd | Financial services | 2010 |
| My Busy Box Ltd | Wholesale & retail | 2025 |
| My Legal Assistance Ltd | Professional & scientific | 2012 |
| My Medical Writing Ltd | Information & communication | 2019 |
| My Perfect Trips Ltd | Administrative & support | 2024 |
| My Poppies Ltd. | Wholesale & retail | 2023 |
| My Property Pro Group Ltd | Real estate | 2025 |
| My Trusted Team Ltd | Information & communication | 2024 |
| MY2BE Enterprises Ltd | Information & communication | 2018 |
| Myar Medical Limited | Health & social care | 2021 |
| Myddelton Offshore Limited | Professional & scientific | 2016 |
| Myerson (EOT) Trust Company Limited | Extraterritorial | 2024 |
| Myerson Limited | Professional & scientific | 2024 |
| Myerson Trust Corporation Limited | Professional & scientific | 2018 |
| Myhelp Ltd | Health & social care | 2020 |
| Myianni IT Limited | Administrative & support | 2023 |
| Myladoor Medical Ltd | Health & social care | 2014 |
| Myles Logic Limited | Information & communication | 2025 |
| Myojo BIO Limited | Professional & scientific | 2007 |
| Mypad Services Ltd | Households | 2024 |
| Mypets Pawfect Limited | Wholesale & retail | 2024 |
| Myranch Foods Limited | Hospitality | 2022 |
| Myriad IT Solutions Limited | Professional & scientific | 2022 |
| Myrimap Limited | Professional & scientific | 2020 |
| Mysn LLP | | 2009 |
| Myst Logistics Ltd | Transport & logistics | 2025 |
| Mystical Brand Ltd | Wholesale & retail | 2023 |
| Mystical Construction Ltd | Construction | 2024 |
| Mystical Logistics Ltd | Transport & logistics | 2025 |
| Mystilucky Ltd | Wholesale & retail | 2025 |
| Mystudentjobuk Ltd | Administrative & support | 2025 |
| Myvitamins Limited | Extraterritorial | 2012 |
| Mônolith Archaeology and Heritage C.I.C. | Professional & scientific | 2026 |
| N & K Events Limited | Arts & recreation | 2022 |
| N . Mcpherson Limited | Professional & scientific | 2025 |
| N H R (UK) Limited | Professional & scientific | 1994 |
| N J Richardson Ltd | Transport & logistics | 2025 |
| N Prasad Shoulder Ltd | Health & social care | 2018 |
| N Tandon Consulting Limited | Professional & scientific | 2025 |
| N&C Developments Ltd | Real estate | 2024 |
| N&H Motors Ltd | Wholesale & retail | 2024 |
| N&Mk Properties Limited | Real estate | 2023 |
| N.A Governance Services Limited | Professional & scientific | 2017 |
| N.D E2E Solutions Ltd | Professional & scientific | 2025 |
| N202 Limited | Real estate | 2024 |
| NA Clinical Consultancy Ltd | Other services | 2026 |
| Nadayenne Ltd | Transport & logistics | 2019 |
| Nadeem Holdings PVT Ltd | Real estate | 2021 |
| Nadeem Medics Limited | Health & social care | 2018 |
| Naes Professional Limited | Information & communication | 2017 |
| Nagle Pipework & Plumbing Ltd | Construction | 2022 |
| Nahar Masala Ltd | Hospitality | 2025 |
| NAI Ortho Limited | Health & social care | 2025 |
| Nailing the Finances Ltd | Education | 2025 |
| Nakilat Ship Management (UK) Limited | Transport & logistics | 2026 |
| NAM Yang Properties Ltd | Real estate | 2019 |
| Namm Solutions Limited | Administrative & support | 2014 |
| Nana Property Ltd | Real estate | 2021 |
| Nanny Kelly Baby Basics Ltd | Education | 2022 |
| Nanoprint Innovations Limited | Professional & scientific | 2023 |
| Nanosmat Ltd | Education | 2011 |
| Nanotib Technology Limited | Professional & scientific | 2026 |
| Nara Energy & Civil Engineering Limited | Administrative & support | 2012 |
| Narlawar Medical Services Ltd | Health & social care | 2017 |
| Narrative Property Limited | Real estate | 2018 |
| Narunari Capital Ltd | Financial services | 2025 |
| Nascol Limited | Professional & scientific | 1953 |
| Nash Delivery Technologies UK Limited | Information & communication | 2022 |
| Nassau Global Credit (UK) LLP | | 2020 |
| Natalie Rayers Revenue Management Ltd | Professional & scientific | 2026 |
| Natanam Limited | Professional & scientific | 2023 |
| Natasha Fitzgerald Solutions Limited | Administrative & support | 2015 |
| Nathan Chandler Limited | Professional & scientific | 2024 |
| National Care Solutions Ltd | Administrative & support | 2018 |
| National Intensive Limited | Wholesale & retail | 2014 |
| National Talent Academy Limited | Education | 2025 |
| Nationwide Consultancy UK Ltd | Construction | 2019 |
| Nationwide Express Distribution LLP | | 2018 |
| Nativ TOV Consultancy Limited | Professional & scientific | 2026 |
| Nats Consulting Limited | Professional & scientific | 2023 |