| Osteotec Europe Ltd | Extraterritorial | 2019 |
| Osteotec Holdings Limited | Manufacturing | 2018 |
| Osteotec Limited | Wholesale & retail | 1993 |
| Osteotech Ltd | Extraterritorial | 2019 |
| OUR Fit Hub Franchise Ltd | Administrative & support | 2025 |
| OUR Fit Hub Ltd | Education | 2021 |
| OUR Fit Hub Newbury Ltd | Arts & recreation | 2025 |
| OUT of the Blue (Penwood) Limited | Professional & scientific | 2002 |
| Outdoor Academy Ltd | Arts & recreation | 2007 |
| Outdoorsy UK Limited | Administrative & support | 2018 |
| Output Fire & Security Ltd | Construction | 2023 |
| Outside Services Ltd | Extraterritorial | 2018 |
| Outside the Box Films Ltd | Information & communication | 2019 |
| Outside-In People Solutions Ltd | Professional & scientific | 2026 |
| Outsidein Property Solutions Ltd | Construction | 2025 |
| Outsource EOT Limited | Information & communication | 2017 |
| Outsource International Limited | Information & communication | 2003 |
| Oval (2308) Limited | Administrative & support | 2019 |
| Over the Top Touring Services Ltd | Transport & logistics | 2023 |
| Overland Environmental Services Limited | Professional & scientific | 2005 |
| Owen Burrows Racing Limited | Agriculture & fishing | 2022 |
| Owens Newco a Limited | Financial services | 2024 |
| Owva Holdings Limited | Financial services | 2026 |
| OX Drove Farm Limited | Administrative & support | 2003 |
| Oxford Bifolds Ltd | Construction | 2015 |
| Oxford Building Supplies Limited | Wholesale & retail | 2003 |
| Oxford Expression Technologies Limited | Professional & scientific | 2006 |
| Oxford Healthtech Ltd. | Professional & scientific | 2018 |
| Oxley Auto Engineers Ltd | Wholesale & retail | 2026 |
| Oxley Consultancy Ltd | Professional & scientific | 2022 |
| Oxstone Ltd | Construction | 2022 |
| Oxvent Limited | Professional & scientific | 2020 |
| OXYGEN365 Ltd. | Information & communication | 2017 |
| Ozgur Mobile Ltd | Other services | 2024 |
| P & F Construction Ltd | Construction | 2018 |
| P & M Diving Services Limited | Arts & recreation | 2021 |
| P & M Homecare Limited | Health & social care | 2007 |
| P C Rimmer Limited | Information & communication | 2022 |
| P D Properties Limited | Construction | 1997 |
| P J Brockbank Ltd | Construction | 2002 |
| P K N Consulting Limited | Financial services | 2001 |
| P&B Browne Ltd | Hospitality | 2019 |
| P&K Cridge Holdings Ltd | Professional & scientific | 2014 |
| P&T Marketplace Ltd | Wholesale & retail | 2025 |
| P. & W.J. Simmons Farmers Limited | Agriculture & fishing | 1958 |
| P.K.B. Electrical & Data Installation Ltd | Construction | 1997 |
| P.T.G. Tours Limited | Transport & logistics | 1999 |
| P.W.H. Management Limited | Households | 2000 |
| Pacificsea Ventures Limited | Real estate | 2017 |
| Pado Logistics Ltd | Transport & logistics | 2020 |
| Padworth Builders Ltd | Construction | 2022 |
| Page Engineering Ltd | Professional & scientific | 2015 |
| Page Turner Awards Ltd | Information & communication | 2021 |
| Painters Palace Ltd | Wholesale & retail | 2017 |
| Palace Golf Consultancy Ltd | Wholesale & retail | 2018 |
| Palam Limited | Professional & scientific | 1995 |
| Pallister Consulting Limited | Professional & scientific | 2026 |
| Palmer (Freehold) Limited | Real estate | 2022 |
| Panda Culinary LAB Ltd | Wholesale & retail | 2025 |
| Panting Project Solutions Ltd | Professional & scientific | 2025 |
| Papa Luigi Pizzaiola Limited | Hospitality | 2010 |
| Paperina Ltd | Hospitality | 2023 |
| Papillon Laundry Services Limited | Wholesale & retail | 2013 |
| Paracode Holdings Limited | Financial services | 2024 |
| Paracode Ltd | Information & communication | 2019 |
| Paradise Peninsula Limited | Financial services | 2025 |
| Paradox Creative Studio Ltd | Professional & scientific | 2025 |
| Paragon Alternative Technologies Ltd | Professional & scientific | 2020 |
| Paramodel Ltd | Manufacturing | 2024 |
| Paratus Law Limited | Professional & scientific | 2016 |
| Parent Investments Limited | Real estate | 2016 |
| Parfitt Pool Lining Services Limited | Construction | 2021 |
| Parham Capital Ltd | Real estate | 2019 |
| Parisa Technologies Limited | Information & communication | 2005 |
| Park Lane (Residents) Limited | Households | 1984 |
| Park Lane Norwich Holdings Ltd | Real estate | 2024 |
| Park Life Install Limited | Administrative & support | 2020 |
| Park Reach Limited | Households | 2018 |
| Parker Wilson Ltd | Administrative & support | 2019 |
| Parkers Financial Solutions Ltd | Financial services | 2014 |
| Parkes International Transport Limited | Transport & logistics | 1994 |
| PARKM8 Limited | Extraterritorial | 2026 |
| Parkside Capital Limited | Professional & scientific | 1999 |
| Parkside House Limited | Real estate | 2015 |
| Parry and Company Limited | Construction | 2021 |
| Parry Lighting Limited | Extraterritorial | 2017 |
| Part and Parcel Ltd | Wholesale & retail | 2010 |
| PARTH4U Limited | Real estate | 2026 |
| Particle Pictures Ltd | Information & communication | 2020 |
| Partnership Communications Ltd | Professional & scientific | 2025 |
| Party Wall Consultant Limited | Professional & scientific | 2013 |
| Patch Productions Limited | Extraterritorial | 2020 |
| Pathfinder Partnerships Limited | Professional & scientific | 2023 |
| Patient Care Domiciliary & Transport Services Ltd | Other services | 2025 |
| Patisserhi Ltd | Hospitality | 2024 |
| Pattern Imprinted Concrete Supplies Limited | Manufacturing | 1991 |
| Paul Endean Home Improvement Services Limited | Construction | 2005 |
| Paul Knight Services Limited | Construction | 2025 |
| Paul Rocker Services Limited | Other services | 2015 |
| Paula Carter Administration Services Limited | Administrative & support | 2005 |