| MRM Architectural Services Limited | Construction | 2006 |
| Mykonos Concierge UK Limited | Professional & scientific | 2003 |
| Myrooh Fitness Ltd | Arts & recreation | 2019 |
| N2 Limited | Information & communication | 2004 |
| NB Medical Limited | Health & social care | 2003 |
| NE Renewable Services Ltd | Professional & scientific | 2024 |
| Neal Recording Systems Limited | Extraterritorial | 1981 |
| Nestways Ltd | Real estate | 1999 |
| Nevis Court (Whitley Bay) Management Company Limited | Households | 1995 |
| New Century Decorators Limited | Professional & scientific | 1999 |
| New Treasure Garden Investments Limited | Professional & scientific | 2003 |
| Newcastle Arts Centre Limited | Wholesale & retail | 1981 |
| Newcastle Arts Centre Trust Limited | Arts & recreation | 1989 |
| Newcastle Blackbelt Academy Ltd | Arts & recreation | 2004 |
| Newcastle United FC Limited | Arts & recreation | 2006 |
| Newcastle United Football Club Limited | Arts & recreation | 2006 |
| Newcastle Upon Tyne World Headquarters Limited | Hospitality | 2000 |
| Newminster Estates Limited | Real estate | 1997 |
| Nial Holdings Limited | Professional & scientific | 2001 |
| Nial Investments Limited | Professional & scientific | 2001 |
| Nichol Goodwill Brown Limited | Professional & scientific | 2003 |
| Nicholson Hall Associates Limited | Professional & scientific | 1995 |
| Nino Pizza ( North East ) Limited | Hospitality | 2015 |
| Nissan European Data Centre Ukeig | Professional & scientific | 1996 |
| Nissan Holdings (UK) Limited | Professional & scientific | 2000 |
| Northeast Properties Direct Limited | Real estate | 2000 |
| Northern Print Studio Limited | Manufacturing | 1994 |
| Northern Sales (2006) Limited | Wholesale & retail | 2006 |
| Northern Spire North East Ltd | Financial services | 2025 |
| Northern Tubs Limited | Manufacturing | 2003 |
| Northpoint Consulting Ltd | Professional & scientific | 2009 |
| Northumbrian Ltd | Education | 2003 |
| Nozimo Limited | Real estate | 2007 |
| Nutrisense Limited | Information & communication | 1999 |
| Nuvacor International Limited | Transport & logistics | 1991 |
| NV Property Holdings Limited | Real estate | 2016 |
| NZS Group Ltd | Other services | 2026 |
| O.J.C. Limited | Hospitality | 2000 |
| Ogbourne Oak Ltd | Real estate | 2025 |
| One Call Air Conditioning Limited | Construction | 2006 |
| Opsec Security Group Limited | Manufacturing | 1982 |
| Opsec Security Limited | Manufacturing | 1986 |
| Optechnique Spectacle Makers Limited | Wholesale & retail | 2005 |
| Optionworth Services Limited | Professional & scientific | 1993 |
| Oracle Consult Ltd | Professional & scientific | 2015 |
| Orion Corporate Group Holdings Limited | Construction | 2025 |
| Osborne Court (Jesmond) Maintenance Limited | Households | 1975 |
| Osborne Professional Services Limited | Other services | 2004 |
| Ossies Hairdressing Limited | Other services | 2003 |
| Otax Limited | Professional & scientific | 2003 |
| Ovington Boats Limited | Manufacturing | 1997 |
| Ovington Holdings Limited | Financial services | 2005 |
| P & S LLP | | 2007 |
| Pacsloof Limited | Energy | 1960 |
| Pantrini PER Sempre Limited | Hospitality | 2007 |
| PAT Robson & Co Limited | Real estate | 1998 |
| Paul Doherty Wealth and Property Management Ltd | Financial services | 2022 |
| Pearson Production Systems Limited | Professional & scientific | 2002 |
| Pellbest Limited | Construction | 1977 |
| Petards International Limited | Extraterritorial | 2000 |
| Petards Joyce-Loebl Limited | Manufacturing | 1987 |
| Petards Limited | Manufacturing | 1988 |
| Peter Eastlake Limited | Construction | 2003 |
| Petersen Stainless Rigging Limited | Manufacturing | 1978 |
| Photo Training Pro Limited | Professional & scientific | 2003 |
| Picklets Ltd | Real estate | 2022 |
| Plants 4 U Ltd | Agriculture & fishing | 2003 |
| PLP Electrics Ltd | Construction | 2005 |
| Popoe UK Ltd | Wholesale & retail | 2006 |
| Posh Wosh (N E ) Limited | Other services | 2005 |
| Pourhana Limited | Hospitality | 2003 |
| Powerhouse Marine Limited | Manufacturing | 1987 |
| Premier Properties (UK) Limited | Real estate | 2002 |
| Prestige Pallets Ltd | Wholesale & retail | 2005 |
| Preston Gate Maintenance Company Limited | Households | 1973 |
| Prime CUT Wholesale Ltd | Wholesale & retail | 1948 |
| Prime Systems Investments Limited | Professional & scientific | 2006 |
| Printing Services (North East) Limited | Manufacturing | 2001 |
| Priors Haven (Management) Limited | Households | 1996 |
| Priors Terrace Management Company Limited | Households | 1984 |
| Priory Training Services Ltd | Administrative & support | 1999 |
| Prizepay Limited | Manufacturing | 1989 |
| Project Property Limited | Professional & scientific | 2003 |
| Pure Imagination Limited | Wholesale & retail | 2002 |
| Quantum Investments Europe Limited | Real estate | 2016 |
| Quarry Services Ltd | Wholesale & retail | 2005 |
| Quay Wall Investments Limited | Real estate | 2003 |
| Quayside Pharmacy Limited | Health & social care | 1992 |
| Quickflash Limited | Wholesale & retail | 1981 |
| Quickflash(Tuning)Limited | Real estate | 1983 |
| R & M Donaldson Limited | Administrative & support | 2005 |
| R & P Roofing Ltd | Construction | 2006 |
| R a Jackson & SON LLP | | 2001 |
| R J Utility Services Ltd | Construction | 1997 |
| R R Fenwick Limited | Construction | 2018 |
| R.S. Vents Limited | Manufacturing | 2000 |
| RAB Outdoor Education Limited | Education | 2003 |
| Ravensworth GC 2016 Limited | Hospitality | 2016 |
| RBS Construction Limited | Wholesale & retail | 2003 |
| Rebecca Waite Ltd | Professional & scientific | 2023 |