| Michelle Lowbridge Limited | Health & social care | 2014 |
| Micmiccrochet Ltd | Wholesale & retail | 2025 |
| Mike Sertin Sports Associates Limited | Arts & recreation | 1989 |
| Mila Dairy Ltd | Manufacturing | 2025 |
| Mildon Ltd | Professional & scientific | 2018 |
| Milosaber Tech Ltd | Real estate | 2021 |
| Mimiz Ltd | Professional & scientific | 2025 |
| Mind the AD Limited | Information & communication | 2011 |
| Mindflow AI Ltd | Information & communication | 2024 |
| Mindful Health Insights Limited | Health & social care | 2020 |
| MKS Accessories Limited | Wholesale & retail | 2021 |
| Moamco Limited | Wholesale & retail | 2020 |
| Moco Property Limited | Real estate | 2021 |
| Modest Visions Ltd | Professional & scientific | 2019 |
| Mojostack Limited | Information & communication | 2021 |
| Molo App Limited | Information & communication | 2024 |
| Momentous Education Group Limited | Education | 2024 |
| Mona Management Consultancy Ltd | Professional & scientific | 2015 |
| Money Mastery Circle Limited | Education | 2020 |
| Monsieur BOP Ltd | Wholesale & retail | 2025 |
| Monsta Media Mayfair Limited | Professional & scientific | 2025 |
| Monticle Limited | Professional & scientific | 2019 |
| Moschou and COX Property Ltd | Real estate | 2015 |
| Mount Megiddo Ltd | Financial services | 2025 |
| Mountain View Global Limited | Wholesale & retail | 2024 |
| MR Baglee Ltd | Professional & scientific | 2011 |
| MR SAJ Ltd | Other services | 2016 |
| MTD Compliance Ltd | Professional & scientific | 2025 |
| Muir Generator Services Limited | Manufacturing | 2016 |
| Mulberri Ltd | Information & communication | 2025 |
| Munstead Limited | Wholesale & retail | 2008 |
| Muse Property Ltd | Real estate | 2023 |
| Myohmy Events Ltd | Other services | 2020 |
| Mystery Star Records Limited | Arts & recreation | 2022 |
| Naaday ALI Surgicals Ltd | Manufacturing | 2025 |
| NAG Investments Ltd | Real estate | 2009 |
| Nai's Post Creations Ltd | Wholesale & retail | 2023 |
| Naked Seed Limited | Manufacturing | 2023 |
| Nansen Green Limited | Professional & scientific | 2018 |
| Natpearce Ltd | Other services | 2025 |
| Natura First Ltd | Wholesale & retail | 2017 |
| Neal Street Neighbours Limited | Households | 1996 |
| Nebulahosting Ltd | Information & communication | 2024 |
| Neon Caltrop Consulting Limited | Professional & scientific | 2023 |
| Neon Star Ltd | Information & communication | 2020 |
| Neuropain Limited | Health & social care | 2015 |
| Neville Rose & Co Limited | Wholesale & retail | 2025 |
| New Pathways Psychology Services Limited | Health & social care | 2022 |
| Nexys Fertility Ltd | Education | 2024 |
| NIA Jones Ltd | Professional & scientific | 2012 |
| Nimble Digital Limited | Professional & scientific | 2010 |
| Nimu Sales and Marketing Limited | Wholesale & retail | 2019 |
| Niyama Essentials Ltd | Wholesale & retail | 2019 |
| NM Speech and Language Therapy Ltd | Health & social care | 2022 |
| Noble Asset Ventures Ltd | Real estate | 2005 |
| NOM B Ltd | Wholesale & retail | 2026 |
| Nomu Studios Ltd | Information & communication | 2025 |
| North Bridge House Ltd | Real estate | 2023 |
| Northbridge Trading Ltd | Wholesale & retail | 2025 |
| Nosniknej Limited | Professional & scientific | 2024 |
| Notos Ltd | Real estate | 2021 |
| Nova-Star Capital Limited | Financial services | 2025 |
| Novaa Solutions Limited | Administrative & support | 2024 |
| Novelex Limited | Information & communication | 2017 |
| Novelicious Books Ltd | Information & communication | 2013 |
| Novikova Consultants Ltd | Hospitality | 2024 |
| NOX Technologies Ltd | Information & communication | 2010 |
| NRW Coaching Limited | Other services | 2021 |
| OAY Procurement Consultancy Ltd | Professional & scientific | 2022 |
| Oceana Group Ltd | Hospitality | 2023 |
| Odyssey by Mina Ltd | Other services | 2025 |
| Ofili Properties Limited | Real estate | 2018 |
| OHR Labs Ltd | Wholesale & retail | 2025 |
| OLA Ugwu Consulting Ltd | Professional & scientific | 2022 |
| One Desire Ltd | Real estate | 2023 |
| Onward Collective Limited | Administrative & support | 2023 |
| Opportuneur LLP | | 2019 |
| Oppy AI Ltd | Professional & scientific | 2025 |
| Optinex Teck Ltd | Information & communication | 2024 |
| Orbifold Software Ltd | Information & communication | 2022 |
| Orchid Studios IV Ltd | Wholesale & retail | 2023 |
| Origins+ Ltd | Information & communication | 2025 |
| Orion Medica Ltd | Health & social care | 2025 |
| ORIVENTA1 Ltd | Financial services | 2025 |
| Oslac Ltd | Construction | 2019 |
| Osratouna Ltd | Wholesale & retail | 2020 |
| Overlays Guru Ltd | Information & communication | 2022 |
| Oxysound Ltd | Information & communication | 2023 |
| Ozdesign Sofa Limited | Wholesale & retail | 2025 |
| P.O.W.E.R. (LSG) Ltd | Wholesale & retail | 2020 |
| P.P. Electro-Mechanical Services Limited | Construction | 2021 |
| Pachamama Film Ltd | Information & communication | 2020 |
| Palaniappan Consulting Limited | Extraterritorial | 2019 |
| Panda Treasure Quest Ltd | Information & communication | 2025 |
| Pansi Limited | Information & communication | 2020 |
| Paracelsus Innovation Limited | Professional & scientific | 2024 |
| Pars Tech Ltd | Information & communication | 2019 |
| Parsik Consulting Ltd | Other services | 2018 |
| Pastel Ltd | Manufacturing | 2022 |
| Path Global UK Limited | Information & communication | 2021 |