| Northstar Plumbing and Heating Ltd | Construction | 2026 |
| Nosh Express Ltd | Hospitality | 2016 |
| Novocast Limited | Information & communication | 1997 |
| Novus Transport Services Ltd | Transport & logistics | 2026 |
| NR Electrical Fire & Security Systems Limited | Construction | 2017 |
| NSP Recruitment Technologies Limited | Information & communication | 2024 |
| Nurture Consultants Ltd | Professional & scientific | 2018 |
| Nutrihub Ltd | Manufacturing | 2024 |
| Nyathi Holdings Limited | Financial services | 2026 |
| O'Connor North East Limited | Administrative & support | 2023 |
| O.Scott Landscaping & Groundworks Limited | Administrative & support | 2019 |
| Oakride Limited | Financial services | 2020 |
| Oakstone Installation Limited | Construction | 2026 |
| Oberlin Filter Limited | Manufacturing | 1999 |
| Occupational Health and Training Services Ltd | Health & social care | 2020 |
| Oceantec Marine Limited | Manufacturing | 2004 |
| Officeoysterwholesale Limited | Wholesale & retail | 2025 |
| OFH Catering Limited | Hospitality | 2017 |
| OFH Parties Limited | Arts & recreation | 2017 |
| Ogden Buckminster Limited | Wholesale & retail | 2024 |
| OMG Photography Ltd | Professional & scientific | 2021 |
| OMP Properties Ltd | Construction | 2026 |
| One 16 Holdings Limited | Financial services | 2026 |
| One World Records Limited | Information & communication | 2019 |
| Onetree Automotive Ltd | Manufacturing | 2019 |
| Oopsies Limited | Wholesale & retail | 2025 |
| Open Format Ltd | Other services | 2017 |
| Optimum Skills Limited | Education | 2013 |
| Option 50/50 Ltd | Other services | 2021 |
| Opulent Odds Limited | Wholesale & retail | 2025 |
| Oscars Leisure Ltd | Wholesale & retail | 2020 |
| OUR Friends in the North Ltd | Information & communication | 2018 |
| OUR FUN House (Middlesbrough) Limited | Arts & recreation | 2017 |
| Outreach North Limited | Health & social care | 2011 |
| OXY - WAX Limited | Extraterritorial | 2013 |
| P and P Gentle Skincare Ltd. | Administrative & support | 2024 |
| P&J Waters Ltd | Transport & logistics | 2024 |
| Paar Engineering Solutions Ltd | Professional & scientific | 2022 |
| Paintshopuk Limited | Wholesale & retail | 2024 |
| Palm Wizards Ltd | Professional & scientific | 2024 |
| Parksite Limited | Construction | 1986 |
| Party Supplies Ltd | Administrative & support | 2018 |
| Paterson's Partitions Ltd | Construction | 2006 |
| Patrick Lonergan Recruitment Ltd | Administrative & support | 2016 |
| Pattinson & Milburn Training Limited | Health & social care | 2010 |
| Paul Manning Utility Services Ltd | Energy | 2014 |
| PB Leisure (NE) Ltd | Hospitality | 2019 |
| PB PUB Solutions Limited | Hospitality | 2026 |
| PDM Industrial Rope Access and Rigging Ltd | Manufacturing | 2014 |
| PDW 070901 Limited | Real estate | 2025 |
| PDW Properties Limited | Transport & logistics | 2025 |
| Peak Performance Sales Ltd | Professional & scientific | 2025 |
| Pear Construction (North) Limited | Construction | 2023 |
| Peareth Financial Ltd | Financial services | 2022 |
| Peikko UK Limited | Manufacturing | 2006 |
| Pejmo Limited | Hospitality | 2020 |
| Perry Process Equipment Limited | Wholesale & retail | 1990 |
| Pesky Pest Limited | Administrative & support | 2020 |
| Pests Taken Care of (Products) Ltd | Wholesale & retail | 2012 |
| Peters Bookkeeping Services Ltd | Other services | 2017 |
| Petite Boutique Childrens Wear Limited | Wholesale & retail | 2016 |
| PF Electrical Ltd | Construction | 2017 |
| Phase 2 Group Limited | Financial services | 2025 |
| Philip Armstrong Construction Limited | Construction | 2011 |
| Pilates Guru Ltd | Arts & recreation | 2019 |
| Pillar III Management Limited | Professional & scientific | 2017 |
| Pimm's and Needles South Durham CIC | Other services | 2023 |
| Pinnacle Properties NE Ltd | Real estate | 2025 |
| Pinnacle Valeting Ltd | Administrative & support | 2026 |
| Pioneering Care Partnership | Other services | 1998 |
| Pipeshield International Ltd | Manufacturing | 1999 |
| Pivotpointuk Limited | Education | 2025 |
| Pizza Taxi Holdings Limited | Hospitality | 2023 |
| Pizza Taxi Limited | Hospitality | 2024 |
| Plak-Form Limited | Manufacturing | 1988 |
| Plant Expo Ltd | Wholesale & retail | 2021 |
| Platinum Facilities Ltd | Administrative & support | 2021 |
| Platinum Short Breaks Ltd | Hospitality | 2023 |
| Playcations Ltd | Administrative & support | 2025 |
| Polipa UK Ltd | Wholesale & retail | 2022 |
| Pollen Street Developments Ltd | Construction | 2024 |
| Pollite Limited | Wholesale & retail | 2009 |
| POP Build Limited | Construction | 2019 |
| Poseidon Engineering Services Ltd | Professional & scientific | 2024 |
| Positive Pirates CIC | Health & social care | 2026 |
| Positrend Limited | Professional & scientific | 2007 |
| Potts Logistics Ltd | Transport & logistics | 2025 |
| Powertool World Limited | Wholesale & retail | 2010 |
| PPS Developments Limited | Real estate | 2014 |
| Precision Groundworks & Civil Engineering Limited | Construction | 2019 |
| Precision Pressure Washing Ltd | Administrative & support | 2025 |
| Prefere Resins UK Holding Limited | Financial services | 2018 |
| Prefere Resins UK Limited | Manufacturing | 2013 |
| Premier Ground Maintenance Ltd | Administrative & support | 2026 |
| Prestige Home & Drive Solutions Ltd | Construction | 2025 |
| Preston Lodge Farm Ltd | Agriculture & fishing | 2022 |
| Pretty Professional Ltd | Wholesale & retail | 2022 |
| Price Contractors Limited | Construction | 2012 |
| Primex Plastics Limited | Manufacturing | 1997 |
| Prior Solutions Limited | Professional & scientific | 2025 |