| Mode Design Limited | Manufacturing | 2020 |
| Moden Retreats Ltd | Hospitality | 2024 |
| Moel Llys Consulting Ltd | Health & social care | 2019 |
| Molly MAE Limited | Manufacturing | 2012 |
| Mondo Stone Limited | Professional & scientific | 2015 |
| Monocroma Ltd | Professional & scientific | 2024 |
| Monty Health Limited | Professional & scientific | 2020 |
| Moore Fleming Limited | Professional & scientific | 2009 |
| Moran Building Services Limited | Information & communication | 2001 |
| Morcott Developments Limited | Other services | 2013 |
| Moreton Group Ltd | Other services | 2025 |
| Moreton Land Hub Limited | Real estate | 2025 |
| Mortons Bistro Limited | Hospitality | 2018 |
| Mostyn Enterprise Park Limited | Construction | 2023 |
| Motchecknbook.Co.Uk Ltd | Information & communication | 2019 |
| Motofibre Ltd | Extraterritorial | 2017 |
| Motorhome Accessory Services Ltd | Wholesale & retail | 2026 |
| Mount Laboratories (UK) Limited | Professional & scientific | 2002 |
| MOV Properties Ltd | Real estate | 2015 |
| MR H Bell Inn Ltd | Hospitality | 2018 |
| MR VET Ltd | Administrative & support | 2014 |
| MS Commercial Ltd | Transport & logistics | 2026 |
| MSW Electrical Services Limited | Construction | 2013 |
| Mullaris Limited | Health & social care | 2019 |
| Multi Recruit Ltd | Administrative & support | 2016 |
| Music for Wellbeing Community Interest Company | Other services | 2022 |
| Musical World (Coventry) Limited | Transport & logistics | 1989 |
| MX Factory Pro Ltd | Wholesale & retail | 2022 |
| My Admin Support Ltd | Administrative & support | 2015 |
| My Little Cake Studio Ltd | Extraterritorial | 2020 |
| My Mustard Ltd | Professional & scientific | 2009 |
| N & L Beswick Limited | Wholesale & retail | 2010 |
| N a Moore Limited | Other services | 2009 |
| N G Properties (Lutterworth) Limited | Real estate | 2026 |
| N T Fencing Contractors Ltd | Construction | 2021 |
| Nadia Minkoff Limited | Professional & scientific | 1950 |
| Nailstone Commercials UK Ltd | Wholesale & retail | 2025 |
| Nano Fibre UK Limited | Information & communication | 2016 |
| Narborough Lettings Ltd | Real estate | 2020 |
| Narborough Ventilation Limited | Construction | 2009 |
| National Fork Rental Ltd | Administrative & support | 2018 |
| National Plant Rental Ltd | Administrative & support | 2018 |
| National Warranties Group Limited | Financial services | 2026 |
| National Warranties Ltd | Professional & scientific | 2026 |
| Nationwide Platforms Limited | Administrative & support | 1988 |
| Navis Wheels Limited | Wholesale & retail | 2021 |
| Navnit Limited | Other services | 2014 |
| Naylor Price Ltd | Other services | 2014 |
| NBJ (London) Ltd | Construction | 2010 |
| NBJ Airfield Park Limited | Financial services | 2016 |
| NCD Vertex Ltd | Real estate | 2026 |
| Neil Green Catering Limited | Hospitality | 2006 |
| Neil Green Holdings Limited | Financial services | 2026 |
| Neil Tressler Building Contractor Limited | Other services | 2002 |
| Nenette Chocolates Ltd | Manufacturing | 2026 |
| Nescol Properties Limited | Real estate | 2013 |
| Netsap Consulting Ltd | Information & communication | 2011 |
| Neutrino Networks Ltd | Information & communication | 2010 |
| New Horizon Innovation Ltd | Professional & scientific | 2020 |
| New Horizons Holdings Ltd | Education | 2015 |
| New Leaf Homes (Leics) Limited | Hospitality | 2024 |
| Newlands Housing Ltd | Real estate | 2021 |
| Newmile Trading Limited | Professional & scientific | 2015 |
| Newstead Goodwin Ltd | Real estate | 2023 |
| Next Key Step Limited | Financial services | 2025 |
| Nexura Limited | Administrative & support | 2017 |
| Nexus Surveying Limited | Professional & scientific | 2025 |
| Nicholas Burfitt Limited | Other services | 2010 |
| Ninetyfold Marriage Settlement Ltd | Professional & scientific | 2015 |
| Ninti Enterprises Ltd. | Financial services | 2012 |
| NJK Projects Limited | Professional & scientific | 2018 |
| NJS Driving Services Limited | Education | 2016 |
| NN Group Holdings Limited | Extraterritorial | 2020 |
| NO. 322 Leicester Limited | Real estate | 1997 |
| Noiseboys Technologies Ltd | Manufacturing | 2009 |
| North Bay Waterpark Limited | Arts & recreation | 2014 |
| North Kilworth Boat Painting Ltd | Manufacturing | 2021 |
| North Kilworth Narrowboat Hire Ltd | Hospitality | 2020 |
| North Kilworth Wharf Limited | Transport & logistics | 2007 |
| North Lincs Metals & Minerals Limited | Professional & scientific | 2020 |
| Northampton Urology Ltd | Other services | 2018 |
| Nova Leaf Limited | Professional & scientific | 2016 |
| NP Care Consultancy Ltd | Administrative & support | 2025 |
| Npotdar Consultants Ltd | Health & social care | 2015 |
| NRG Incorporated Ltd | Energy | 2025 |
| NS Consultancy Ltd | Construction | 2024 |
| Nurayden Ltd | Health & social care | 2025 |
| Nutricomms Consultancy Ltd | Health & social care | 2016 |
| Nuts About Performance Limited | Professional & scientific | 2022 |
| Oakapple Processing Limited | Manufacturing | 2003 |
| Oakberry Trees Limited | Administrative & support | 2006 |
| Oakbridge Business Finance Limited | Financial services | 2024 |
| Oakham Mobility & Healthcare Limited | Wholesale & retail | 2011 |
| Oakleaf Property Management (Midlands) Ltd | Construction | 2024 |
| Oasis Laundry Equipment Ltd | Wholesale & retail | 2026 |
| Obdurate Limited | Information & communication | 2004 |
| Ockelton Advisory Ltd | Administrative & support | 2026 |
| Octagon Performance Ltd | Arts & recreation | 2025 |
| Ohana Care Group Limited | Health & social care | 2025 |
| Old House Farm Management Ltd | Households | 2020 |