| Maison Berber Ltd | Wholesale & retail | 2022 |
| Malka Foods Ltd | Manufacturing | 2020 |
| Manjula Ltd | Health & social care | 2011 |
| Mansi Consultancy Ltd | Information & communication | 2016 |
| Marlborough Management (Wimbledon) Limited | Administrative & support | 1982 |
| Maya Neer Ltd | Real estate | 2025 |
| MDA Structures Limited | Professional & scientific | 2009 |
| Medical Fact Courses Ltd | Education | 2017 |
| Medo Properties Ltd | Real estate | 2018 |
| Meds Resources Ltd | Administrative & support | 2021 |
| Merchant Navy Ratings Pension Fund Trustees Limited | Financial services | 1965 |
| Meyer Mundell Limited | Financial services | 2022 |
| Microbee Tree Management Limited | Administrative & support | 2008 |
| Midlands Surveyors Ltd | Households | 2025 |
| Midnight Draft Studios Ltd | Information & communication | 2025 |
| Mikelli London Limited | Real estate | 2018 |
| Miller House Limited | Information & communication | 2024 |
| Mind the Education Ltd | Education | 2020 |
| Mint Green Limited | Other services | 2003 |
| Mistral Digital Ltd | Information & communication | 2024 |
| MJF Commercial Property Limited | Real estate | 2020 |
| MJT Studio Ltd | Professional & scientific | 2024 |
| MKH Repair & Maintenance Ltd | Administrative & support | 2024 |
| Mokka Holdings Limited | Financial services | 2020 |
| Momo Living Ltd | Real estate | 2025 |
| Mona Doll London Ltd | Wholesale & retail | 2023 |
| Moneta Markets Capital Ltd | Financial services | 2012 |
| Moose Bikes Ltd | Wholesale & retail | 2022 |
| Morrishcomms Limited | Professional & scientific | 2015 |
| Mountain Goat Properties Limited | Real estate | 2022 |
| Movers 247 Group Ltd | Transport & logistics | 2025 |
| MPC Property Developments Limited | Real estate | 2014 |
| MS Business Consultants Ltd | Professional & scientific | 2016 |
| Msjr Property Limited | Real estate | 2024 |
| MTK Global Group Limited | Information & communication | 2015 |
| MUL Consulting Ltd | Information & communication | 2018 |
| Musicalities Limited | Information & communication | 1998 |
| N AAK Limited | Real estate | 2014 |
| Naga Healthy Food Solutions Limited | Wholesale & retail | 2021 |
| Nahuda UK Limited | Education | 2016 |
| Najat Capital Investments Ltd | Financial services | 2020 |
| Napanthla Health Limited | Real estate | 2024 |
| Nardi (GB) Limited | Wholesale & retail | 1998 |
| Nartio Limited | Information & communication | 2023 |
| National Bank of New Zealand Limited(The) | | 1985 |
| Natural Science.Com Limited | Wholesale & retail | 1999 |
| Naventa Ltd | Information & communication | 2025 |
| Nelson & Russell Holdings Limited | Manufacturing | 1999 |
| Nelson Pharmacies Limited | Wholesale & retail | 1983 |
| Neri House Limited | Real estate | 1967 |
| New Generation Cars Limited | Other services | 2012 |
| Next Development Limited | Wholesale & retail | 2021 |
| Nexus Build Hub (UK) Limited | Construction | 2025 |
| NFH R1 Limited | Hospitality | 2025 |
| NFH R2 Limited | Hospitality | 2025 |
| NFH Restaurants Ltd | Hospitality | 2022 |
| NGB Fit Ltd | Other services | 2023 |
| Nineteen Group Limited | Real estate | 2011 |
| Nishyashi PVT Ltd | Information & communication | 2023 |
| NJP Plumbing Limited | Construction | 2007 |
| NO Signal Games Ltd | Information & communication | 2023 |
| NOG Animation Ltd | Information & communication | 2021 |
| Northkin Limited | Wholesale & retail | 2016 |
| Notanx Apnea Limited | Education | 2017 |
| Nova Clear Exterior Solution Limited | Administrative & support | 2026 |
| Number One Draxmont Management Limited | Real estate | 1978 |
| Nwandei Estate Limited | Real estate | 2016 |
| Nwandei Limited | Financial services | 2012 |
| Oaklawn (Arthur Road) Residents Limited | Households | 1986 |
| Ocean Moon Property Holdings Ltd | Real estate | 2024 |
| Octave London Ltd | Construction | 2018 |
| Old House Close Wimbledon Residents Association Limited | Households | 1961 |
| Olive Tree (Clacton) Limited | Hospitality | 2009 |
| Olive Tree Estates Limited | Professional & scientific | 2004 |
| Oliver Kinross Build Limited | Administrative & support | 2015 |
| Oliver Kinross Limited | Administrative & support | 2007 |
| Oliver Sanderson USA Ltd | Wholesale & retail | 2024 |
| Omega Trade and Finance Ltd | Professional & scientific | 2026 |
| One Accord Surveyors Ltd | Professional & scientific | 2020 |
| One Strategy Studio Ltd | Information & communication | 2023 |
| ONE80 Technology Group Ltd | Information & communication | 2023 |
| Onkho Ltd | Information & communication | 2013 |
| Onslow Square Property Limited | Real estate | 2022 |
| Options Direct Ltd | Wholesale & retail | 2014 |
| Optisolutions Limited | Administrative & support | 2024 |
| Orange Media Limited | Information & communication | 2022 |
| Outlier Grove LLP | | 2024 |
| Owen Property | Real estate | 1971 |
| Oxberry Capital and Consulting Ltd | Information & communication | 2020 |
| Oxon Consultancy Ltd | Real estate | 2025 |
| P H C & C Limited | Professional & scientific | 2005 |
| P J Foley Ltd | Construction | 2017 |
| P S Pillay Limited | Health & social care | 2020 |
| P.S.Baker Limited | Construction | 2001 |
| Padvinder Two Limited | Financial services | 2026 |
| Pagagist Limited | Administrative & support | 2008 |
| Pagara DOC Ltd | Health & social care | 2020 |
| Paige Cavell Ltd | Arts & recreation | 2019 |
| Palace Plant Hire Limited | Other services | 1972 |
| Palette Lighting Ltd | Manufacturing | 2019 |