| Moving Office Limited | Professional & scientific | 2008 |
| MR & MRS Gardening Company Ltd | Arts & recreation | 2024 |
| MR Tyres (Andover) Limited | Wholesale & retail | 2011 |
| MR2 Developments Limited | Financial services | 2021 |
| MR2 Holdings Limited | Construction | 2010 |
| Mrbc Properties Limited | Real estate | 2014 |
| Mrhh Limited | Health & social care | 2024 |
| Mrmonk Limited | Transport & logistics | 2011 |
| MRO Logistics Limited | Manufacturing | 2013 |
| Mrowiec Trans Ltd | Transport & logistics | 2022 |
| MRT Castings Limited | Manufacturing | 1996 |
| MS Motorworx Limited | Wholesale & retail | 2018 |
| MSA Serafin Limited | Transport & logistics | 2021 |
| MSH Professional Services Limited | Professional & scientific | 2024 |
| Msps PVT Ltd | Health & social care | 2020 |
| MTF Air Conditioning Ltd | Energy | 2022 |
| MTF Rail Ltd | Construction | 2023 |
| MTR Trans Ltd | Wholesale & retail | 2018 |
| Mucho Marketing Ltd | Professional & scientific | 2026 |
| Muddy Runners Ltd | Arts & recreation | 2018 |
| Mulaan Properties Limited | Real estate | 2021 |
| Mulberry Plumbing & Heating Limited | Construction | 2018 |
| Mulberry Property Holdings Ltd | Construction | 2025 |
| Mulberry Rocks Property Ltd | Real estate | 2025 |
| Multax Group Ltd | Financial services | 2026 |
| Multax Limited | Manufacturing | 2016 |
| Multi Media Replication Limited | Information & communication | 1992 |
| Multitask Operations Limited | Real estate | 2010 |
| Mumbai Brasserie Ltd | Hospitality | 2017 |
| Mumshonesttake Ltd | Professional & scientific | 2025 |
| Muse-It Financial Limited | Information & communication | 2025 |
| Muster Inns Limited | Hospitality | 2011 |
| Muze Creative Ltd | Professional & scientific | 2013 |
| MW Garage Ltd | Wholesale & retail | 2026 |
| MWM Logistics Ltd | Transport & logistics | 2017 |
| MWU Tree Services Ltd | Agriculture & fishing | 2018 |
| MX5 Parts Warehouse Ltd | Wholesale & retail | 2020 |
| Mykeypeople Ltd | Information & communication | 2011 |
| Myrna House Residents Association Limited | Households | 1993 |
| Mysupportroom Ltd | Information & communication | 2020 |
| N Colley Consulting Limited | Professional & scientific | 2025 |
| N M Doyle Limited | Professional & scientific | 2019 |
| N Smith Financial Services Ltd | Professional & scientific | 2021 |
| N&N Associates Ltd | Professional & scientific | 2015 |
| N-Xen LLP | | 2025 |
| Naads Online Ltd | Wholesale & retail | 2025 |
| Nadder Holdings Limited | Financial services | 2019 |
| Nadra Safiri Ltd | Wholesale & retail | 2020 |
| Nailing IT Ltd | Other services | 2025 |
| Namukupa Driving .Co.Uk Ltd | Other services | 2018 |
| Nanologic Ltd | Information & communication | 2024 |
| Nanoscale Limited | Professional & scientific | 2023 |
| Naomi O'Hara Permanent Cosmetics Limited | Other services | 2014 |
| Naomi O'Hara Training Academy Limited | Education | 2016 |
| Nate Korl Tech Limited | Professional & scientific | 2021 |
| National Home Contractors Limited | Construction | 2025 |
| National Mental Health Nurse Directors Forum | Other services | 2007 |
| Natsy Ltd | Administrative & support | 2016 |
| Nature Photographers Limited | Professional & scientific | 1992 |
| Naturearb Ltd | Agriculture & fishing | 2025 |
| Naylor Logistics Ltd | Wholesale & retail | 2024 |
| NB Cleaning Ltd | Construction | 2019 |
| NB Cricket Coaching Ltd | Education | 2025 |
| NB Wealth Management Ltd | Financial services | 2012 |
| ND Installations Ltd | Construction | 2021 |
| NED & Advisory Services Limited | Information & communication | 2019 |
| Neecer Ltd | Wholesale & retail | 2026 |
| Neet Systems Ltd | Information & communication | 2025 |
| Nelson & Sons Demolition Ltd | Construction | 2008 |
| Nelson Asset Management Ltd | Real estate | 2008 |
| Nelson Brothers Ltd | Water & waste | 2014 |
| Nelson Group of Companies Ltd | Financial services | 2022 |
| Nelson Plant Hire Limited | Administrative & support | 2006 |
| Nelson Recycling Ltd | Water & waste | 2010 |
| Neotrans Ltd | Transport & logistics | 2020 |
| Ness.Poseidon Ltd | Transport & logistics | 2022 |
| NET0PLUS Ltd | Other services | 2026 |
| New Barn Equestrian Services Ltd | Agriculture & fishing | 2018 |
| New Intelligence Ltd | Other services | 2017 |
| New Pathways Healthcare Limited | Health & social care | 2020 |
| New Retail Solutions Ltd | Professional & scientific | 2019 |
| New Yard Partnership LLP | | 2007 |
| Newman H C Limited | Health & social care | 2025 |
| Newport Business Improvement Limited | Professional & scientific | 2025 |
| Nexmove Logistics Ltd | Transport & logistics | 2024 |
| Nexus SCS Limited | Professional & scientific | 2025 |
| Nicholas Howard Ltd | Administrative & support | 2009 |
| Nicki James Limited | Professional & scientific | 2017 |
| Nicolas M Limited | Construction | 2024 |
| Nightingale Floor Limited | Administrative & support | 2023 |
| Nineteen 77 Media Limited | Professional & scientific | 2018 |
| Nineteen Seventy Three Vintage Ltd | Wholesale & retail | 2025 |
| Ninknonk Ltd | Health & social care | 2018 |
| Nixy Limited | Information & communication | 2023 |
| NKL Consultancy Ltd | Professional & scientific | 2014 |
| NO Trace Apparel Ltd | Manufacturing | 2025 |
| Nord-Lock Ltd | Manufacturing | 2000 |
| Nordedge Ltd | Professional & scientific | 2025 |
| Norg Secretarial Ltd | Professional & scientific | 2010 |
| Norris Bloodstock Limited | Other services | 2015 |