| Mugnai Digital Services Ltd | Information & communication | 2024 |
| Mugnai Oncology Services Ltd | Professional & scientific | 2026 |
| Muhasib Peer Limited | Professional & scientific | 2019 |
| Muini Group Ltd | Wholesale & retail | 2025 |
| Mulberry Care Services Limited | Health & social care | 2016 |
| Mulberry Park LOW Fell Management Company Limited | Households | 1998 |
| Mulcahy Smith Limited | Professional & scientific | 2017 |
| Mulgrave Audio Ltd | Information & communication | 2023 |
| Mullen Media Limited | Information & communication | 2024 |
| Multi Utility Services Limited | Construction | 2017 |
| Munich Estates Ltd | Real estate | 2019 |
| Murray Mcgowan Scaffolding Limited | Construction | 1999 |
| Musgrave School Management Limited | Real estate | 2006 |
| Mushu Tattoo Ltd | Other services | 2022 |
| Music Education Council Limited | Other services | 2022 |
| Music North Limited | Arts & recreation | 2001 |
| MUY Canny Ltd | Hospitality | 2026 |
| MVA Property Advisory Ltd | Administrative & support | 2024 |
| MW Trades Ltd | Professional & scientific | 2026 |
| MWD Medical Ltd | Health & social care | 2022 |
| My Blue Eyed View Limited | Wholesale & retail | 2018 |
| My Books & Beyond Ltd | Professional & scientific | 2023 |
| My Boomerang Group Ltd | Financial services | 2022 |
| My Consultancy Services (North East) Limited | Other services | 2023 |
| My Dog Barber (LF) Limited | Other services | 2017 |
| My Fingers Ltd | Wholesale & retail | 2025 |
| My Locum Accountants Limited | Professional & scientific | 2024 |
| My Secret Santorini Limited | Hospitality | 2015 |
| Myjobmag Limited | Information & communication | 2025 |
| Myleadmachine Ltd | Professional & scientific | 2021 |
| Mypac Limited | Extraterritorial | 2024 |
| Myriad Online Limited | Information & communication | 2009 |
| MYY Property Ltd | Real estate | 2022 |
| Müller GAS Tech Ltd | Construction | 2019 |
| N & a Investments Northeast Ltd | Real estate | 2024 |
| N & B Chemists Limited | Wholesale & retail | 1985 |
| N and I Investments and Tradings Ltd | Real estate | 2017 |
| N Botan Limited | Health & social care | 2014 |
| N E Construction & Civils Ltd | Administrative & support | 2017 |
| N I White Electrical Contractor Limited | Construction | 2020 |
| N L Autos Limited | Manufacturing | 2019 |
| N M Caraian Ltd | Health & social care | 2013 |
| N Properties Ltd | Real estate | 2016 |
| N S D (UK) Ltd. | Wholesale & retail | 2010 |
| N&D Building Services Ltd | Construction | 2025 |
| N&P Paving Ltd | Administrative & support | 2026 |
| N. Jeffrey and Company Ltd | Professional & scientific | 2022 |
| N. Purdy & Co. Limited | Construction | 1985 |
| N.E Meats Limited | Wholesale & retail | 2013 |
| N.R.G's Recordbox Limited | Wholesale & retail | 2026 |
| N.U Homecare Ltd | Health & social care | 2025 |
| NA NE Estate Ltd | Real estate | 2023 |
| Nabk Ltd | Administrative & support | 2016 |
| NAD Holdings Ltd | Professional & scientific | 2026 |
| Nada Fund | Information & communication | 2025 |
| Nadeea Hair Design Ltd | Other services | 2019 |
| Nadlan Anglia Ltd | Real estate | 2020 |
| Nadlee Group Ltd | Professional & scientific | 2021 |
| Nadlee Payroll Ltd | Administrative & support | 2018 |
| Nadon 55 Ltd | Hospitality | 2012 |
| Nadon Newcastle Ltd | Hospitality | 2015 |
| Nafisat Imperial Enterprises Limited | Wholesale & retail | 2024 |
| Nafizas Ltd | Hospitality | 2019 |
| Nahagim Limited | Other services | 2019 |
| Naija Food Square Ltd | Wholesale & retail | 2025 |
| Nails TS Ltd | Other services | 2025 |
| NAJ Dent Ltd | Health & social care | 2025 |
| Najeb NE Properties Ltd | Real estate | 2024 |
| Nalazek Transport Ltd | Transport & logistics | 2024 |
| Nanach House Ltd | Construction | 2022 |
| Nancyrita Surveyors Ltd | Professional & scientific | 2024 |
| Nanda Medical Services Ltd | Health & social care | 2011 |
| Nandi Clubs Ltd | Real estate | 2022 |
| Nano Creative Ltd | Administrative & support | 2017 |
| Nano-Purification Solutions Ltd | Manufacturing | 2007 |
| Nanthan Superstores Ltd | Wholesale & retail | 2022 |
| Napca Computing Limited | Information & communication | 2018 |
| Naradent Ltd | Health & social care | 2023 |
| Nasif Ltd | Administrative & support | 2024 |
| Nates Bait Ltd | Hospitality | 2025 |
| National Allparts Limited | Extraterritorial | 1976 |
| National Care Network (Franchising) Ltd | Health & social care | 2023 |
| National Care Network Ltd | Health & social care | 2021 |
| National Claims Surveyors Limited | Professional & scientific | 2018 |
| National FM Services Ltd | Administrative & support | 2022 |
| National Green Energy Limited | Professional & scientific | 2024 |
| Nationwide Chimney Components Ltd | Construction | 2002 |
| Natural Landscapes North East Limited | Construction | 2021 |
| Natural Landscapes Solutions Limited | Administrative & support | 2015 |
| Natural Landscaping Solutions Limited | Administrative & support | 2024 |
| Natural World Energy Ltd | Other services | 2023 |
| Nautical Management Services Limited | Administrative & support | 2017 |
| Navaya Group Ltd | Real estate | 2026 |
| Naveen Recruitment Ltd | Administrative & support | 2024 |
| Navigator Signing Solutions Limited | Professional & scientific | 2005 |
| Nayak Limited | Health & social care | 2024 |
| Nazanna Services Ltd | Wholesale & retail | 2026 |
| Naztaj Ltd | Administrative & support | 2019 |
| NB Residential Properties Ltd | Real estate | 2024 |
| NC Utility Services Ltd | Wholesale & retail | 2025 |