| Marsil Bedlington Ltd | Extraterritorial | 2021 |
| Martin France Consultancy Ltd | Extraterritorial | 2011 |
| Mary Convenience Store (NE) Ltd | Wholesale & retail | 2021 |
| Masterman Estates Ltd | Financial services | 2025 |
| Masterman Financial Services Ltd | Financial services | 2013 |
| Matrix Projects Limited | Construction | 2026 |
| Mattamy Dental Care Ltd | Health & social care | 2014 |
| MC Digital Consultancy Limited | Information & communication | 2025 |
| Meadowview Van & Car Sales Limited | Wholesale & retail | 2021 |
| Medi GAS Global Ltd | Professional & scientific | 2025 |
| Meer Barbers NE Ltd | Other services | 2024 |
| Metalis Engineering Limited | Mining & quarrying | 2022 |
| MJ Lightfoot Painting and Decorating Ltd | Construction | 2020 |
| Mltaylor Ltd | Construction | 2025 |
| MNP Decorating Ltd | Construction | 2010 |
| Moja Kitchen Ltd | Hospitality | 2025 |
| Mojo Community Events CIC | Professional & scientific | 2022 |
| Monsoon Cuisine Newcastle Limited | Hospitality | 2026 |
| Monsoon NE Ltd | Hospitality | 2023 |
| Mood Hospitality Limited | Real estate | 2022 |
| Morris and Mcgrady Limited | Arts & recreation | 2023 |
| MP Precision Limited | Manufacturing | 2001 |
| MPA Contracts Ltd | Arts & recreation | 2016 |
| MRS O'S Caring Hands Homecare Limited | Health & social care | 2016 |
| Mulgrove Bolting Ltd | Manufacturing | 2024 |
| Murther Fire Protection Ltd | Construction | 2022 |
| Murther Interiors Ltd | Construction | 2024 |
| Mustang Errands.Co.Uk Ltd | Transport & logistics | 2025 |
| Mxdeventsncl Ltd | Administrative & support | 2025 |
| Myersoft Limited | Manufacturing | 2007 |
| N M a Processing Pipeline Services Limited | Professional & scientific | 2016 |
| N Wright Industrial Access Ltd | Professional & scientific | 2024 |
| Natasha Edwards Healthcare Ltd | Health & social care | 2026 |
| Naturalight Commercials Ltd | Transport & logistics | 2021 |
| Naturalight Holdings Ltd. | Financial services | 2011 |
| Naturalight Properties Ltd. | Real estate | 2011 |
| Naturalight Systems Limited | Manufacturing | 2001 |
| NAZ Barber NE Ltd | Other services | 2021 |
| NE1 Roofing Limited | Construction | 2024 |
| Neil Richardson Interiors Ltd | Construction | 2021 |
| Nejt Catering Limited | Hospitality | 2026 |
| New Bombay Nights Ltd | Hospitality | 2019 |
| New Power Solar Ltd | Construction | 2023 |
| Newburn Container Storage Limited | Other services | 2025 |
| NEX Joinery Limited | Manufacturing | 2025 |
| Nexfabrication Ltd | Manufacturing | 2025 |
| Nextgen Agility Ltd | Administrative & support | 2025 |
| Nexus Coatings Ltd | Manufacturing | 2025 |
| Nicholsmith Ltd | Manufacturing | 2020 |
| Nield TM Ltd | Extraterritorial | 2019 |
| Niki French Consultancy Limited | Other services | 2018 |
| Noble House Savings Limited | Financial services | 2022 |
| North East Cake Supplies Limited | Hospitality | 2011 |
| North East Estate Agents Ltd | Real estate | 2023 |
| North East Flooring Solutions Limited | Construction | 2020 |
| North East GAS and OIL Services Limited | Mining & quarrying | 2020 |
| North East Organic Growers Limited | Agriculture & fishing | 1996 |
| North East Property Surveyors Ltd | Real estate | 2022 |
| North East Traffic Management Ltd | Construction | 2018 |
| Northeast Paving Ltd | Construction | 2020 |
| Northern Industrial Factors Limited | Manufacturing | 2021 |
| Northumberland Driveways & Patios Limited | Construction | 2021 |
| Northumberland Driveways Limited | Construction | 2014 |
| Northumberland Healthcare Limited | Agriculture & fishing | 2025 |
| Northumberland Parent Carer Forum CIC | Education | 2024 |
| Northumberland Roofing Services Ltd | Construction | 2025 |
| Northumbria Commercial Lettings Ltd | Real estate | 2026 |
| Northumbria Recycling Limited | Water & waste | 2007 |
| Northumbrian Markets Limited | Real estate | 2009 |
| Northumbrian Profiles Ltd | Manufacturing | 2022 |
| Northumbrian Properties Ltd | Real estate | 2022 |
| Northumbrian Tech Limited | Wholesale & retail | 2023 |
| NR Roofing and Property Services Limited | Construction | 2024 |
| NXG Holdings Ltd | Financial services | 2025 |
| Objective 61 Ltd | Information & communication | 2023 |
| OIL Rush World Wide Ltd | Professional & scientific | 2020 |
| Oliver Refine Aesthetics Ltd | Other services | 2025 |
| Oliver Site Services Ltd | Other services | 2024 |
| OP Engineering Ltd | Other services | 2024 |
| Orchidvale Consultancy Ltd | Public administration | 2014 |
| Osbornes Jewellers Limited | Wholesale & retail | 2010 |
| Otistcg Ltd | Wholesale & retail | 2026 |
| Oval Barbers Ltd | Other services | 2025 |
| Overs and Rich Limited | Arts & recreation | 1975 |
| P Y Chemicals Limited | Wholesale & retail | 2011 |
| Panda 2026 Limited | Hospitality | 2026 |
| Panda Oriental Lucky Grow Ltd | Hospitality | 2025 |
| Paramount Fitness & Wellness Ltd | Arts & recreation | 2026 |
| Paramount Health (North East) Limited | Health & social care | 2016 |
| Park View Care (North East) Limited | Health & social care | 2011 |
| Parks Skips Ltd | Water & waste | 2020 |
| Parnell Products Ltd | Wholesale & retail | 2006 |
| Paul Robert Graham Bolting Ltd | Manufacturing | 2018 |
| Paula Light Cognitive Hypnotherapy Ltd | Health & social care | 2016 |
| Paybot Ltd | Information & communication | 2026 |
| Penny Black Antiques Limited | Wholesale & retail | 2022 |
| Perks Automotive Ltd | Wholesale & retail | 2020 |
| Perks Motor Company Ltd | Wholesale & retail | 2025 |
| PG Brickwork Ltd | Construction | 2022 |
| PGS Traffic & Transport Limited | Extraterritorial | 2020 |