| MTH Shopping Ltd | Wholesale & retail | 2023 |
| MTK Investments Limited | Real estate | 2025 |
| MTM Roofing & Cladding Ltd | Construction | 2021 |
| MTS Planning Ltd | Professional & scientific | 2025 |
| Muacha Limited | Hospitality | 2019 |
| Muda Club Hartlepool Ltd | Hospitality | 2025 |
| Mudd Construction Ltd | Construction | 2020 |
| Mudie Heating & Plumbing Services Ltd | Construction | 2026 |
| Mudita Health Limited | Health & social care | 2025 |
| Mudita Law Limited | Professional & scientific | 2024 |
| Mufasa Group Ltd | Administrative & support | 2023 |
| Muhammed Mustafa Kosif Ltd | Wholesale & retail | 2025 |
| Mullen Stoker IT Management Limited | Information & communication | 2014 |
| Mullen Stoker Limited | Professional & scientific | 2010 |
| Mungan Trade Ltd | Wholesale & retail | 2025 |
| Munoz Kitchen Ltd. | Hospitality | 2025 |
| Murphy Heath Ltd | Professional & scientific | 2016 |
| Murray Memorials Limited | Professional & scientific | 2001 |
| Murtek Communications Ltd | Information & communication | 2023 |
| Musical Mates Ltd | Education | 2013 |
| Musicworks (England) Limited | Education | 2010 |
| Mustard & - Community Interest Company | Professional & scientific | 2019 |
| Mutleys Dog Boutique Ltd | Wholesale & retail | 2025 |
| Mutlins Doggy Day Care and Grooming Ltd | Agriculture & fishing | 2025 |
| Muztard Ltd | Hospitality | 2025 |
| MV Deignan Limited | Information & communication | 2025 |
| MWG NE Ltd | Construction | 2025 |
| MWS Topco Limited | Professional & scientific | 2022 |
| My Barber Shop Limited | Other services | 2025 |
| My Blue EYE Limited | Hospitality | 2026 |
| My Lasting Legacy Ltd | Professional & scientific | 2022 |
| My Space Ltd | Real estate | 2019 |
| Myartbrief Ltd | Arts & recreation | 2015 |
| Myhomeismyhappy Interiors Ltd | Professional & scientific | 2022 |
| Mykinda Travel Ltd | Wholesale & retail | 2010 |
| MYP (NE) Limited | Real estate | 2024 |
| N & D Durham Limited | Professional & scientific | 2018 |
| N & L Gandhi FIC Limited | Financial services | 2025 |
| N D Properties (North East) Ltd | Real estate | 2022 |
| N E Parking Services Limited | Transport & logistics | 2024 |
| N K & E Y Ltd | Hospitality | 2017 |
| N M Lee’S Limited | Construction | 2026 |
| N T Group Holdings Limited | Real estate | 2019 |
| N&V Cheek Holdings Limited | Financial services | 2024 |
| N. Alderson Funeral Director Ltd | Other services | 2006 |
| N. J. N. Catering Services U.K. Limited | Wholesale & retail | 2002 |
| N.A.M Groundworks Ltd | Construction | 2021 |
| N.E. Accountancy Services Limited | Professional & scientific | 2005 |
| N.L.R.R. Groundworks Ltd | Construction | 2021 |
| N.Oor Jewellery Limited | Wholesale & retail | 2010 |
| NA Barbering Limited | Other services | 2017 |
| Nabosh Logistics Ltd | Transport & logistics | 2024 |
| Nacu Ltd | Wholesale & retail | 2025 |
| Naija Taste Pantry Limited | Wholesale & retail | 2026 |
| Nanang Keys Limited | Wholesale & retail | 2025 |
| Nandppubs Limited | Hospitality | 2023 |
| Nani Laser & IPL Ltd | Other services | 2023 |
| Naps Properties Ltd | Real estate | 2024 |
| Narmiku Limited | Wholesale & retail | 2026 |
| Nascent Semiconductor Limited | Professional & scientific | 2021 |
| Natalie Thompson Limited | Education | 2016 |
| Nathan Armin Utilities Ltd | Energy | 2022 |
| Nation Core Ltd | Administrative & support | 2025 |
| National Vehicle Solutions Limited | Wholesale & retail | 2006 |
| National Youth Choirs of Great Britain | Education | 1984 |
| Nationwide Brickwork Limited | Construction | 2015 |
| Nationwide Design, Construction and Maintenance Limited | Administrative & support | 2009 |
| Nattress Property Limited | Construction | 2006 |
| Naturamedix Ltd | Wholesale & retail | 2025 |
| Naturra Livefoods Ltd | Agriculture & fishing | 2025 |
| Natzone Overage Limited | Real estate | 2018 |
| Navigate the Curve Ltd | Education | 2023 |
| Nbct Properties Limited | Real estate | 2022 |
| NBD (UK) Ltd | Arts & recreation | 2011 |
| NC EDM Services Ltd | Professional & scientific | 2010 |
| NC Utilities & Groundworks Ltd | Construction | 2026 |
| NCH Plant Services Ltd | Wholesale & retail | 2016 |
| ND Renting and Leasing Limited | Wholesale & retail | 2018 |
| NDT Inspection Limited | Professional & scientific | 2007 |
| NE Capital Group Limited | Financial services | 2025 |
| NE Hospitality Ltd | Hospitality | 2019 |
| NE Lettings Ltd | Real estate | 2020 |
| NE Pumps Limited | Administrative & support | 2023 |
| NE Spray Solutions Ltd | Construction | 2025 |
| NE Store 24 Ltd | Other services | 2025 |
| NE1 | Other services | 2005 |
| NEA Legal Limited | Professional & scientific | 2026 |
| Neasham Road JV Limited | Construction | 2020 |
| Nebtix Limited | Wholesale & retail | 2024 |
| Necit (North America) Limited | Professional & scientific | 2020 |
| Necit Holdings Limited | Financial services | 2020 |
| Necit Services Limited | Professional & scientific | 2009 |
| Nedce Company Limited | Manufacturing | 2023 |
| NEF Manco Limited | Households | 2024 |
| Nefp Fire Protection Services Ltd | Public administration | 2017 |
| NEG Construction Ltd | Construction | 2017 |
| Neil & Gary's Pet Care Ltd | Other services | 2019 |
| Neil Henderson Consulting Engineers Ltd | Professional & scientific | 2020 |
| Neil Walker Building Services Ltd | Construction | 2018 |
| Neil Webster Transport Ltd | Transport & logistics | 2008 |