| Newcastle Buttress Limited | Real estate | 2007 |
| Nivee Ltd | Real estate | 2024 |
| NJ 360 Limited | Real estate | 2023 |
| Njmm Holdings Ltd | Financial services | 2025 |
| NM Bros Ltd | Real estate | 2021 |
| NM Enterprise (NE) Ltd | Wholesale & retail | 2021 |
| NM Enterprises NE Ltd | Wholesale & retail | 2023 |
| NMO Properties Limited | Real estate | 2017 |
| Noble's Bingo Limited | Arts & recreation | 2025 |
| Nord Tile Limited | Construction | 2019 |
| Nordae Ltd | Wholesale & retail | 2026 |
| Norman Court Properties Ltd | Real estate | 2019 |
| North Durham Sports Academy CIC | Education | 2020 |
| North East Autism Society | Education | 1993 |
| North East Darts Ltd | Other services | 2022 |
| North East Grass Management Ltd | Other services | 2019 |
| North East Manna Limited | Hospitality | 2025 |
| North East Property People Limited | Information & communication | 2014 |
| North Lodge Consultants Ltd | Professional & scientific | 2022 |
| North of England Leisure Ltd | Wholesale & retail | 2021 |
| Northeast Wheelie Clean Ltd | Administrative & support | 2026 |
| Northeastlocksmiths Limited | Manufacturing | 2015 |
| Northern FLS Ltd | Professional & scientific | 2024 |
| Northern Hope Centre Limited | Arts & recreation | 2013 |
| Northern Maintenance (Chester-Le-Street) Ltd | Administrative & support | 2002 |
| Northern Redevelopments Ltd | Construction | 2026 |
| Northern Sparkle Limited | Administrative & support | 2021 |
| Northfix Ltd | Construction | 2019 |
| Northlands Camper Company Limited | Wholesale & retail | 2026 |
| Northumberland Leisure Caravans Limited | Hospitality | 2023 |
| Northumberland Living (Alnwick) Limited | Real estate | 2023 |
| Northumberland Living Guide Ltd | Other services | 2025 |
| Northumberland Living Interiors Ltd | Other services | 2025 |
| Northumberland Living Ltd | Other services | 2025 |
| Northumberland Luxury Stays Ltd | Administrative & support | 2023 |
| Northumberland Square Homes Ltd | Real estate | 2021 |
| NOT Just a Pretty Face Photobooth Ltd | Arts & recreation | 2014 |
| NOT My Problem Ltd | Information & communication | 2026 |
| Nova Wedding Coordinators Ltd | Hospitality | 2023 |
| Novatech (UK) Limited | Wholesale & retail | 1989 |
| Nremts Grill Limited | Hospitality | 2026 |
| NRP (North-East) Ltd | Real estate | 2021 |
| NS Executive Search & Consulting Ltd | Administrative & support | 2024 |
| Nuwall Luxe Limited | Wholesale & retail | 2024 |
| Nyagri Service's Limited | Agriculture & fishing | 2018 |
| O.Shaw Construction Ltd | Construction | 2019 |
| Oak Commercials NE Ltd | Transport & logistics | 2024 |
| Oak House Estates Limited | Construction | 2017 |
| Oak House Homes Limited | Real estate | 2015 |
| Oakapple Associates Ltd | Financial services | 2007 |
| Oakley Estates (Northeast) Limited | Real estate | 2004 |
| ODD JOB Done Limited | Construction | 2018 |
| Ofarm Ltd | Hospitality | 2025 |
| Offshore Construction Management Limited | Construction | 2013 |
| Okapi Pens Ltd | Wholesale & retail | 2021 |
| Old Brewery House Holdings Limited | Financial services | 2021 |
| On-Site Land Solutions Limited | Real estate | 1999 |
| One Click Mall Limited | Wholesale & retail | 2024 |
| One Coaching Group UK Limited | Administrative & support | 2021 |
| One Future International Ltd | Professional & scientific | 2024 |
| One Group North East Limited | Education | 2021 |
| One Sports Warehouse Limited | Wholesale & retail | 2016 |
| One Stop Bathroom & Cladding Shop Ltd | Wholesale & retail | 2018 |
| One Stop Payroll Solution Ltd | Professional & scientific | 2025 |
| Onepoint Systems Ltd | Information & communication | 2003 |
| Oneworld Innovation UK Ltd | Administrative & support | 2022 |
| Orbse Limited | Real estate | 2024 |
| Orchard Roofing Limited | Administrative & support | 2015 |
| ORG Developments Limited | Construction | 2024 |
| Orio Ltd | Manufacturing | 2023 |
| Orio Properties Ltd | Real estate | 2026 |
| Oscar Properties (NE) Limited | Real estate | 2023 |
| Ottimo Cleaning Services Ltd | Administrative & support | 2020 |
| Ouston Car Sales Limited | Wholesale & retail | 2017 |
| Ouston Community Association Limited | Other services | 2008 |
| Ouston Fish Grill Ltd | Hospitality | 2026 |
| Ouston Service Station Limited | Real estate | 2012 |
| Outdoor Relaxing Ltd | Construction | 2025 |
| Outright Hydraulics Limited | Professional & scientific | 2022 |
| Over the Hill Farmsteading Ltd | Real estate | 2011 |
| Overleafai Systems Ltd | Information & communication | 2025 |
| Owen Building Contractors Ltd | Construction | 2006 |
| Owens Trade Solutions Limited | Wholesale & retail | 2025 |
| Oyamilenu Simplified Solutions Ltd | Information & communication | 2024 |
| Oyster Property and GAS Services Ltd | Real estate | 2019 |
| P & L Accountancy Services Ltd | Other services | 2003 |
| P & W Utility Services Limited | Construction | 2021 |
| P. D. Fish & Chips Ltd | Hospitality | 2025 |
| P.C Roofline & Joinery Ltd | Construction | 2020 |
| PAID2TRADE Limited | Wholesale & retail | 2024 |
| Paige Dalziel Properties Ltd | Real estate | 2026 |
| Pallet Supplies Limited | Manufacturing | 2019 |
| Pane E Vino Catering Ltd | Hospitality | 2025 |
| Paperghosts Ltd | Manufacturing | 2020 |
| Paragon Workwear Ltd | Wholesale & retail | 2025 |
| Paramount Fire Solutions Ltd | Construction | 2025 |
| Parhen Contracting Limited | Financial services | 2016 |
| Park Road Group Limited | Wholesale & retail | 2025 |
| Park View Academy | Education | 2011 |
| Park View Community Centre | Arts & recreation | 2012 |