| MHW Consulting Limited | Administrative & support | 2003 |
| Michael Prescott Education Services Limited | Education | 2013 |
| Middlepeak Motor Factors Limited | Wholesale & retail | 2001 |
| Midex Equipment Rental Limited | Administrative & support | 2016 |
| Midland AG Ltd | Professional & scientific | 2023 |
| Midland Commercial Property Rentals Ltd | Real estate | 2015 |
| Midland Excavator Hire Limited | Mining & quarrying | 1995 |
| Midland Industrial Agencies Ltd | Manufacturing | 2004 |
| Midlands HGV Services Ltd | Wholesale & retail | 2025 |
| Midlands Landbased Training Centre Ltd | Administrative & support | 2026 |
| Midlands PM Ltd | Professional & scientific | 2025 |
| Mikijohns Enterprises Limited | Real estate | 1978 |
| Mikijohns Limited | Wholesale & retail | 1983 |
| Mill Town Consultancy Ltd | Administrative & support | 2019 |
| Millbrook Estates Limited | Real estate | 2003 |
| Millers Damsel Limited | Manufacturing | 1989 |
| Millswood Education Services Limited | Education | 2021 |
| Mining One UK Ltd | Information & communication | 2026 |
| Misplaced Apostrophe Film's Limited | Information & communication | 2022 |
| Mistral Technologies Limited | Information & communication | 1996 |
| Mitech Joinery Limited | Manufacturing | 2012 |
| MMG Performance Ltd | Wholesale & retail | 2020 |
| Moatley Ltd | Manufacturing | 2019 |
| Mobilemike Limited | Information & communication | 2025 |
| MODR8 Ltd | Wholesale & retail | 2025 |
| Mogo Farm Ltd | Wholesale & retail | 2024 |
| Monnac Technology LP | | 2012 |
| Moonbase Motorsport Limited | Wholesale & retail | 2018 |
| Moore Civil Engineering Ltd | Construction | 2020 |
| Moorland Arts Trust Limited | Arts & recreation | 2004 |
| Morabbi Construction Limited | Real estate | 2013 |
| Morris-Consultancy Limited | Professional & scientific | 2025 |
| Morrison Fork Truck Services Limited | Manufacturing | 2007 |
| MS 2000 Limited | Professional & scientific | 2013 |
| MT Joinery & Building Ltd | Construction | 2017 |
| Mugginton Village Hall Company | Real estate | 2007 |
| Mulino Lodge Ltd | Hospitality | 2014 |
| Murotex Limited | Wholesale & retail | 2024 |
| N Demmert Ltd | Wholesale & retail | 2018 |
| N J Titterton Limited | Construction | 2004 |
| N. Thompson Holdings Limited | Financial services | 2020 |
| N.F.J. Green Limited | Other services | 1984 |
| Nadia Morley Associates Ltd | Professional & scientific | 2017 |
| Namco Solutions Ltd | Professional & scientific | 2008 |
| Nash Mclean Ltd | Wholesale & retail | 2018 |
| Nasis Limited | Information & communication | 2010 |
| National Fallen Stock Company Limited | Extraterritorial | 2009 |
| Nature Connected Coaching Limited | Information & communication | 2025 |
| Navan Commercials Ltd | | 2023 |
| Naylor Construction Ltd | Construction | 2005 |
| Naylor Plant Hire and Excavations Limited | Administrative & support | 2002 |
| NBF Management Company Limited | Households | 2007 |
| ND Inns Limited | Hospitality | 2023 |
| Ndou Accounting Services Ltd | Professional & scientific | 2024 |
| Ndou Northern Goods Limited | Wholesale & retail | 2022 |
| Ndou Properties Ltd | Real estate | 2022 |
| Neil Ellis Joinery & Building Services Limited | Construction | 2003 |
| Neil Spencer Limited | Wholesale & retail | 2008 |
| Nenplas Holdings Limited | Manufacturing | 2013 |
| Nenplas Limited | Manufacturing | 2006 |
| Nether LEY Ltd | Real estate | 2020 |
| Nethermore Ltd. | Agriculture & fishing | 2003 |
| New Creations NOW Ltd | Wholesale & retail | 2021 |
| New Draycott in the Clay Store Ltd | Wholesale & retail | 2021 |
| New Generation Electrical Services Limited | Construction | 1999 |
| New Look Landscaping Ltd | Administrative & support | 2023 |
| NEX Holdings Ltd | Administrative & support | 2016 |
| Nextedd Limited | Professional & scientific | 2015 |
| Nfsco CIC | Administrative & support | 2004 |
| NG Crofts Holdings Limited | Financial services | 2021 |
| Nicklin Biomass Limited | Administrative & support | 2017 |
| Nifty Logistics Ltd | Transport & logistics | 2016 |
| Nigel R Davis Limited | Professional & scientific | 2004 |
| Nigel's Butchers Ltd | Wholesale & retail | 2002 |
| Nine Barbers Limited | Other services | 2021 |
| NK Rail Solutions Limited | Professional & scientific | 2022 |
| Noble Minds Ltd | Health & social care | 2024 |
| Norbuck Homes Limited | Real estate | 2024 |
| Norseman Estates Limited | Real estate | 1992 |
| Norseman Investments Limited | Extraterritorial | 2001 |
| Northern Mallets Ltd | Arts & recreation | 2026 |
| Northwood Accessories Limited | Wholesale & retail | 2000 |
| Nottingham City Living Limited | Construction | 2003 |
| Nozwaldo Holding Co Ltd | Financial services | 2025 |
| NSG Solutions Ltd | Hospitality | 2024 |
| Nu:U Aesthetics Ltd | Other services | 2021 |
| Nutreco Limited | Financial services | 1994 |
| O'Meara Solutions Ltd | Professional & scientific | 2024 |
| O'Shea Property Holdings Ltd | Construction | 2023 |
| Oak Field Agri Limited | Professional & scientific | 2015 |
| Oak Hotels Ltd | Hospitality | 2012 |
| Oakley Landscape Designs Limited | Administrative & support | 2005 |
| Oakwell Products Limited | Manufacturing | 2001 |
| Oakwood Audio Limited | Information & communication | 2017 |
| OBD Store Ltd | Wholesale & retail | 2025 |
| OFF the Pegg (Ashbourne) Limited | Other services | 2003 |
| Ohlsson Limited | Professional & scientific | 2014 |
| Old Orchard Lane Limited | Real estate | 2026 |
| Olive Tree Travel Limited | Administrative & support | 2011 |
| OMERI21 Construction Ltd | Construction | 2024 |