| Onenuo Ltd | Other services | 2024 |
| Online Angel Limited | Administrative & support | 2009 |
| Onlypari Limited | Real estate | 2021 |
| Onplan Consulting Ltd | Information & communication | 2020 |
| Opal Developments (ST Neots) Limited | Construction | 2015 |
| Opal Rehabilitation Services Limited | Health & social care | 2026 |
| Open Door Church (ST. Neots) | Other services | 2016 |
| Optimise Facilities Management Ltd | Administrative & support | 2018 |
| Optimum Catering Ltd | Manufacturing | 2025 |
| Optirve Ltd | Other services | 2023 |
| Opus Durum Ltd | Extraterritorial | 2012 |
| Opusag Ltd | Professional & scientific | 2024 |
| Orange Alarms Ltd | Information & communication | 2017 |
| Orbis Fitness Ltd | Arts & recreation | 2007 |
| Orion Industries Ltd | Construction | 2024 |
| Ormskirk Eats Limited | Hospitality | 2021 |
| Osak Ltd | Other services | 2018 |
| Otaa ST Neots Property Ltd | Real estate | 2023 |
| Otsc Barbers Ltd | Other services | 2024 |
| Outfoxed Media Limited | Information & communication | 2011 |
| Outlign Studio Ltd | Information & communication | 2025 |
| Over Power Fitness (ST Neots) Ltd | Arts & recreation | 2023 |
| Owens Holdings Ltd | Professional & scientific | 2015 |
| Owens Property Lettings Ltd | Real estate | 2015 |
| Oxbridge UK Interests Ltd | Professional & scientific | 2018 |
| Oxford Academic Sciences Group Ltd | Information & communication | 2022 |
| P & R Bathroom Installations Ltd | Construction | 2011 |
| P C & J Limited | Construction | 2007 |
| P G Roberts Limited | Information & communication | 2005 |
| P Skinner Installations Limited | Construction | 2019 |
| P.O.S. System Ltd | Administrative & support | 2024 |
| Pacino DE Niro Ltd. | Information & communication | 2023 |
| Page Electrical Services Ltd. | Administrative & support | 2017 |
| Panchal Family Trustee Limited | Administrative & support | 2021 |
| Panona Ltd | Other services | 2024 |
| Paramics Limited | Manufacturing | 1984 |
| Pario Marketing Ltd. | Professional & scientific | 2023 |
| Park IT & Server Relocation Services Limited | Information & communication | 2000 |
| Partners Construction & Maintenance Ltd | Construction | 2023 |
| Partslogic Ltd | Information & communication | 2026 |
| Past Life Clothing Limited | Extraterritorial | 2024 |
| Patmu Limited | Health & social care | 2015 |
| Paul Bath Ltd. | Construction | 2002 |
| Paul Bayer Training Limited | Information & communication | 2010 |
| Paul Cherry Plumbing and Heating Services Limited | Construction | 2011 |
| Paul Rook Media Limited | Information & communication | 2024 |
| Pawley Court Residents Management Company Limited | Households | 2018 |
| Paws Paddle Centre Limited | Agriculture & fishing | 2022 |
| Paxigate Healthcare Limited | Health & social care | 2020 |
| Paxton Electrical Limited | Manufacturing | 2014 |
| Paxton Hill Garage Ltd. | Manufacturing | 2015 |
| Paxton Property Services Ltd | Construction | 2025 |
| PB Logistics (Solutions) Ltd | Transport & logistics | 2020 |
| Peach Consultants Limited | Public administration | 1996 |
| Peak Enterprise Solutions Ltd | Professional & scientific | 2023 |
| Pearl PM Solutions Ltd | Professional & scientific | 2025 |
| Pearlocum Limited | Public administration | 2019 |
| Peirsonmedia Ltd | Information & communication | 2026 |
| Pellico Ltd | Manufacturing | 2026 |
| Penine Court Management Limited | Households | 2000 |
| Pennington Consultancy Limited | Information & communication | 2020 |
| Peppercorn House (Eaton Socon) Management Company Limited | Households | 2005 |
| Perart Ltd | Other services | 2021 |
| Perfect Gardens & Landscapes Ltd | Administrative & support | 2016 |
| Pesky Small Squad Limited | Professional & scientific | 2025 |
| Peter Carter Ltd. | Construction | 2004 |
| Peter Chandler - CCA Ltd | Professional & scientific | 2015 |
| Peter Chandler Consultancy Ltd | Other services | 2024 |
| Petmonkey Limited | Wholesale & retail | 2018 |
| PGS Carpets Ltd | Wholesale & retail | 2019 |
| Phantom Corporation Ltd | Education | 2022 |
| Pheasantland Ltd | Real estate | 2017 |
| Philip Coles Plumbing Limited | Construction | 2003 |
| Phone Campus Ltd | Wholesale & retail | 2022 |
| Photofabrication Holdings Limited | Professional & scientific | 2007 |
| Photonix Solutions Limited | Information & communication | 2024 |
| Pidaya Ltd | Extraterritorial | 2021 |
| PIN UPS (ST Neots) Limited | Other services | 2024 |
| Pipeline P&H Limited | Construction | 2020 |
| Pipeworks Heating and Plumbing Ltd | Construction | 2012 |
| Pipistrelle Close Management Limited | Households | 2003 |
| Piram Services Ltd | Other services | 2018 |
| Planting Justice Ltd | Professional & scientific | 2024 |
| Platinum Tours Ltd. | Transport & logistics | 2017 |
| Platinumgroupuk Ltd | Hospitality | 2025 |
| Playnotes Ltd | Education | 2011 |
| Pluggin Baby Ltd | Professional & scientific | 2015 |
| Plukera Ltd | Real estate | 2023 |
| Plumb Graphic Installations Limited | Professional & scientific | 2014 |
| Pnpr Limited | Professional & scientific | 2013 |
| Poco Imagework Ltd | Information & communication | 2017 |
| Pomelo Labs Ltd | Information & communication | 2026 |
| Pomum Limited | Professional & scientific | 2017 |
| Pool Stars Limited | Education | 2022 |
| Port Clearance Services Ltd | Transport & logistics | 2019 |
| Port Holme Properties Ltd. | Real estate | 2020 |
| Porterhouse Brokers LLP | | 2010 |
| Portoport Limited | Extraterritorial | 2002 |
| Poseidon Software Solutions Limited | Information & communication | 2004 |
| Posh&Ziba Company Ltd | Wholesale & retail | 2022 |