| OTS Underfloor Heating & Screeding Ltd | Construction | 2025 |
| Oudprestige Limited | Wholesale & retail | 2021 |
| Oudémoire Ltd | Wholesale & retail | 2025 |
| Ouse Homes Limited | Construction | 2020 |
| OUT of Many Media / Productions Ltd | Administrative & support | 2016 |
| Outdoor Avenue LP | | 2004 |
| Outer Nest Ltd | Wholesale & retail | 2024 |
| Outreach Music Group CIC | Arts & recreation | 2023 |
| Outset Studio Group Ltd | Information & communication | 2018 |
| OV Investments Limited | Financial services | 2026 |
| OV Potential Ltd | Administrative & support | 2026 |
| OV Property Investments Ltd | Real estate | 2020 |
| OVA Cargo Limited | Transport & logistics | 2018 |
| Ovation Consultants Ltd. | Information & communication | 1998 |
| Ovation Consultants Management Limited | Real estate | 2007 |
| Over 50 Fitness Flex Ltd | Manufacturing | 2025 |
| Overproof Bakes Ltd | Manufacturing | 2023 |
| Overseas Bitumen &OIL Distribution Ltd | Wholesale & retail | 2022 |
| Overstone Group Limited | Real estate | 2026 |
| Ovessa Investments Limited | Wholesale & retail | 2021 |
| OVI Contractors Ltd | Construction | 2020 |
| Ovle Ltd | Information & communication | 2025 |
| OVR Beverages Ltd | Wholesale & retail | 2025 |
| OVY95 Limited | Administrative & support | 2025 |
| Owatrol UK Ltd | Wholesale & retail | 2010 |
| Owens Solicitors Limited | Professional & scientific | 2013 |
| Owentha Ltd | Transport & logistics | 2019 |
| Owlmatic Ltd | Wholesale & retail | 2024 |
| Owoxchange Limited | Wholesale & retail | 2026 |
| OX Fone Accessories Limited | Construction | 2019 |
| Oxdpr Limited | Professional & scientific | 2020 |
| Oxford Crest Consultancy Limited | Education | 2026 |
| Oxford Gifts Ltd | Wholesale & retail | 2018 |
| Oxford International Cultural Centre Limited | Administrative & support | 2014 |
| Oxford Mart Limited | Wholesale & retail | 2025 |
| Oxford Mews Limited | Real estate | 2025 |
| Oxford Supramolecular Biotechnology Limited | Manufacturing | 2019 |
| Oxford William Family Office Ltd | Financial services | 2013 |
| OZ Air Limited | Transport & logistics | 1997 |
| Ozam Property Ltd | Real estate | 2021 |
| Ozne Ltd | Wholesale & retail | 2025 |
| Ozone Group Property Services Ltd | Professional & scientific | 2019 |
| Ozone Group UK Ltd | Information & communication | 2024 |
| Ozone Music Limited | Information & communication | 2015 |
| Ozzlebox Ltd. | Information & communication | 2016 |
| Ozzy Engineering Limited | Construction | 2019 |
| P & L Commercial Ltd | Wholesale & retail | 2024 |
| P & M Financial Ltd | Financial services | 2018 |
| P & R Property (Luton) LLP | | 2008 |
| P -Cutzz -Barbers Limited | Health & social care | 2026 |
| P Brothers Limited | Wholesale & retail | 2020 |
| P Builders Ltd | Construction | 2026 |
| P C Lavin Utilities Limited | Construction | 2024 |
| P Dempsey Plant Limited | Administrative & support | 2023 |
| P Doherty Technical Services Limited | Construction | 2015 |
| P Downey Limited | Construction | 2010 |
| P Higgs Ltd | Construction | 2026 |
| P J D Enterprises Ltd | Real estate | 2017 |
| P J W Development Limited | Real estate | 1989 |
| P Jacobs Building Services Limited | Construction | 2026 |
| P M Eaton (Mobile) Limited | Wholesale & retail | 2002 |
| P M Property Solutions Limited | Real estate | 2025 |
| P R a B Investments Limited | Real estate | 2016 |
| P R T Pianos Limited | Wholesale & retail | 2010 |
| P&A Food & Wine Ltd | Wholesale & retail | 2025 |
| P&A Rampley Ltd | Construction | 2019 |
| P&A Tutoring Ltd | Education | 2024 |
| P&D Consultants Limited | Professional & scientific | 2026 |
| P&H Investment Group Ltd | Real estate | 2021 |
| P&M Windows Limited | Construction | 2017 |
| P&V Contractors Ltd | Construction | 2020 |
| P&V Painting & Decorating Ltd | Construction | 2026 |
| P&Z Building Services Ltd | Construction | 2021 |
| P.K.B-Joinery Ltd | Construction | 2019 |
| P.S. Millan Limited | Financial services | 2009 |
| P.S. Sahney & Co Limited | Wholesale & retail | 1983 |
| P.S. Sahney (Holdings) Limited | Financial services | 2019 |
| P.S.T Import & Export Consultants Limited | Wholesale & retail | 2002 |
| P3 (Kettering Gateway Management Company) Ltd | Real estate | 2019 |
| P3 Brooke Limited | Extraterritorial | 2015 |
| PA Commerce Ltd | Wholesale & retail | 2026 |
| PA Grocery Ltd | Wholesale & retail | 2026 |
| PA Smart Engineering Ltd | Manufacturing | 2023 |
| PA Supplies Ltd | Wholesale & retail | 2025 |
| PAA Testing Ltd | Information & communication | 2007 |
| Paas Property Ltd | Real estate | 2018 |
| PAB Consulting Ltd | Professional & scientific | 2023 |
| PAC Construction Projects Limited | Construction | 2008 |
| Pacific TUR Ltd | Wholesale & retail | 2026 |
| Pacioli Payroll Limited | Administrative & support | 2024 |
| Pack & Go Relocation Limited | Transport & logistics | 2024 |
| Pacman Pizza Ltd | Hospitality | 2021 |
| Padda Construction PVT Limited | Construction | 2025 |
| Pade's Restaurant Ltd | Hospitality | 2016 |
| Padel Squared Limited | Arts & recreation | 2025 |
| Pade’S Cafe/ Restaurant Ltd | Hospitality | 2026 |
| Padma Express Limited | Transport & logistics | 2017 |
| Paganel Ltd | Transport & logistics | 2017 |
| Pagg Limited | Information & communication | 2007 |
| Pagicle Ltd | Professional & scientific | 2021 |