| Morley Curd Limited | Professional & scientific | 1995 |
| Mortgage Knowledge Limited | Financial services | 2013 |
| Mortgage PTX Ltd | Financial services | 2023 |
| Motor Ring Ltd | Wholesale & retail | 2019 |
| Motoristas UK Limited | Arts & recreation | 2023 |
| Moving Trends Ltd | Real estate | 2014 |
| MP Tmsa Limited | Real estate | 2021 |
| Mpwr Connect Ltd | Information & communication | 2025 |
| Mrjp Holdings Limited | Construction | 2017 |
| MRK 1 Property Services Limited | Construction | 2012 |
| MRS Softee Sevenoaks Limited | Hospitality | 2026 |
| MSW Holdings (Feltham) Limited | Real estate | 2023 |
| MSW Holdings London SW Limited | Real estate | 2024 |
| Mswali Ltd | Information & communication | 2011 |
| MTM Sash Windows Ltd | Construction | 2019 |
| MTM Windows Ltd | Construction | 2025 |
| Multi Door Service Limited | Construction | 2002 |
| Mumbai WOK Ltd | Hospitality | 2012 |
| Murchfilms Limited | Information & communication | 2024 |
| Murray's Plumbing and Heating Limited | Construction | 2015 |
| Murray's Sports Promo Ltd | Wholesale & retail | 2026 |
| Muscle Ease Ltd | Health & social care | 2002 |
| Musical and Theatrical Enterprises Limited | Arts & recreation | 1964 |
| Mustang Group Ltd | Administrative & support | 2017 |
| Mustang Washrooms Limited | Administrative & support | 2006 |
| MVA Logistics Ltd | Transport & logistics | 2026 |
| My Choice of Care Ltd | Health & social care | 2022 |
| My Choice Properties Investment Ltd | Real estate | 2024 |
| My Creative Limited | Arts & recreation | 2010 |
| My Families Home Ltd | Real estate | 2023 |
| My Families Luxury SA Ltd | Real estate | 2023 |
| My Holiday Transfers Ltd | Transport & logistics | 2022 |
| N and C Services Ltd | Real estate | 2019 |
| N Down Limited | Information & communication | 2014 |
| N K Books Limited | Professional & scientific | 2002 |
| N10 Ltd | Construction | 2021 |
| Nactive Ltd | Wholesale & retail | 2025 |
| Naedlae Haircare Ltd | Manufacturing | 2023 |
| Nagpaul Medical Ltd | Health & social care | 2018 |
| Naked Greens Ltd | Hospitality | 2026 |
| Nash Cleaning Limited | Other services | 2018 |
| Natures Health Hub - Collective Ltd | Wholesale & retail | 2024 |
| Natz Pet Products Ltd | Wholesale & retail | 2025 |
| NBC (Nothing BUT Cleaning) Ltd | Administrative & support | 2015 |
| ND Osteopathy Limited | Health & social care | 2023 |
| ND Whiting Building Services Limited | Construction | 2023 |
| NDL Plumbing Ltd | Construction | 2019 |
| NDS Consultancy Ltd | Professional & scientific | 2026 |
| Neeru RCK Properties Ltd | Real estate | 2022 |
| Neil Gear Video and Photography Ltd | Information & communication | 2013 |
| Nekisse Homes Ltd | Real estate | 2021 |
| Nelehgiel Limited | Information & communication | 2008 |
| Nello's Ltd | Hospitality | 2026 |
| Neon Properties Ltd | Construction | 2019 |
| NET IT Consultancy Ltd | Information & communication | 2012 |
| Neuxpark Associates Ltd | Administrative & support | 2026 |
| New Crane Trading Limited | Wholesale & retail | 2014 |
| New Generation Sports Limited | Education | 2016 |
| New London Cleaning Limited | Administrative & support | 2024 |
| New Pegasus Ltd | Information & communication | 2010 |
| New Starlight Limited | Construction | 2025 |
| New Vision Kent Limited | Real estate | 2019 |
| Newdawn Electrical Limited | Construction | 2017 |
| Newfin Ltd | Professional & scientific | 2023 |
| Newton Place Healthcare LLP | | 2012 |
| Newview Windows & Doors Ltd | Construction | 2003 |
| Nexa Digital Ltd | Wholesale & retail | 2025 |
| Nexphase Accounting Limited | Professional & scientific | 2025 |
| Nextlease Limited | Construction | 1999 |
| Nextstage Marketing Ltd | Professional & scientific | 2025 |
| Nexttier Coaching Ltd | Professional & scientific | 2025 |
| Nexus Manufacturing Limited | Manufacturing | 1969 |
| NIC SFS Ltd | Construction | 2024 |
| Nick London Productions Limited | Information & communication | 2001 |
| Nicky Properties Limited | Real estate | 1985 |
| Nimora Ltd | Information & communication | 2025 |
| Nine Project Management Limited | Construction | 2026 |
| Nitya Investments Limited | Real estate | 2022 |
| Nixci Ltd | Information & communication | 2023 |
| NM RYE Limited | Wholesale & retail | 2013 |
| Noconsultancy Services Limited | Professional & scientific | 2015 |
| Nodachi Ltd | Information & communication | 2012 |
| Nola Specialist Ltd | Professional & scientific | 2012 |
| Norman Projects Limited | Professional & scientific | 2018 |
| North Bridge Funding Ltd | Financial services | 2013 |
| Northfield Property Investments 2 Ltd | Real estate | 2023 |
| Northfield Property Investments Ltd | Real estate | 2022 |
| Northstone Holdings Ltd | Real estate | 2025 |
| Nova Associates Limited | Wholesale & retail | 2010 |
| NOW Boarding Pet Hotels Limited | Hospitality | 2013 |
| NR Business Services Ltd | Professional & scientific | 2012 |
| Nrci Ltd | Wholesale & retail | 2024 |
| NSA Consultancy Services Ltd | Other services | 2017 |
| Nuevox Consulting Limited | Wholesale & retail | 2014 |
| Nurvia Care Ltd | Administrative & support | 2026 |
| Nutmead Investments Limited | Real estate | 2021 |
| NZR Glazing and Maintenance Ltd | Construction | 2025 |
| O & S Gorrie Properties Limited | Real estate | 2024 |
| O'Briens Electrical Limited | Construction | 2012 |
| O'Briens Properties Ltd | Real estate | 2018 |