| Okeland Properties Ltd | Real estate | 2021 |
| Old Pharmacy Court Management Co. Limited | Households | 1982 |
| Olive & Eden Ltd | Hospitality | 2026 |
| OMR Applications Ltd | Information & communication | 2026 |
| One Empire Ltd | Wholesale & retail | 2020 |
| One Stop Testing Equipment Limited | Construction | 2009 |
| Onnekas Limited | Professional & scientific | 2000 |
| Opake Limited | Information & communication | 2015 |
| Open Plan Homes Ltd | Construction | 2025 |
| Oppheim Solutions Ltd | Real estate | 2023 |
| Optimum Value Limited | Professional & scientific | 2011 |
| Oragon Limited | Information & communication | 2003 |
| Orbit Tech Group Ltd | Wholesale & retail | 2023 |
| Orillion Solutions Ltd | Professional & scientific | 2018 |
| Orpheus Consulting Limited | Professional & scientific | 2023 |
| Ortasio Limited | Real estate | 2025 |
| Outcome Focussed Change Ltd | Professional & scientific | 2018 |
| OUTSOURCED2 Ltd | Administrative & support | 2023 |
| Over the Top Valet Ltd | Administrative & support | 2026 |
| OW Tennis Ltd | Arts & recreation | 2026 |
| Owen Wood Recruitment Ltd | Administrative & support | 2023 |
| Oxford Safety Consultancy Ltd | Professional & scientific | 2015 |
| Oyster Outcomes Ltd | Professional & scientific | 2019 |
| P L Auto Services Limited | Wholesale & retail | 2000 |
| P&C Tech Consultants Limited | Information & communication | 2020 |
| Pacific Ventures Limited | Wholesale & retail | 2004 |
| Pallyboo Limited | Information & communication | 2009 |
| Papa Beni Ltd | Hospitality | 2023 |
| Paragon Pension Services Ltd | Financial services | 2010 |
| Parkside Clinic Limited | Other services | 2020 |
| Paul and BEN Limited | Wholesale & retail | 2024 |
| Paul Bennett Consulting Ltd | Professional & scientific | 2013 |
| Pauls Floors Limited | Construction | 2000 |
| Pavilion Interiors Lavershot Ltd | Wholesale & retail | 2020 |
| Pavilion Interiors Trading Ltd | Wholesale & retail | 2020 |
| PBT Consultants Limited | Professional & scientific | 2014 |
| PDG Logistics Ltd | Construction | 2019 |
| Peace Laundrette Ltd | Other services | 2023 |
| Pearl Coaching and Consulting Ltd | Professional & scientific | 2019 |
| Peninsula Place Management Limited | Households | 2003 |
| Penton Freehold Limited | Households | 2021 |
| Peter Llanwarne Limited | Information & communication | 1998 |
| Peter Tickner Associates Limited | Professional & scientific | 2009 |
| PFS Plastics Ltd | Manufacturing | 2012 |
| PGF Planning Limited | Professional & scientific | 2012 |
| Philippe Louviot Ltd | Administrative & support | 2020 |
| Phipps Building Ltd | Construction | 2015 |
| PI Beta Consulting Limited | Professional & scientific | 2012 |
| Pimento Connection Ltd | Administrative & support | 2008 |
| Pineappz Limited | Professional & scientific | 2021 |
| PINNACLE20 Limited | Professional & scientific | 2025 |
| Pipesmart Limited | Construction | 2015 |
| Pipettelab Ltd | Professional & scientific | 2015 |
| PK55 Ltd | Information & communication | 2024 |
| PKB Accountants Limited | Professional & scientific | 2015 |
| Platinum Resolutions Limited | Administrative & support | 2020 |
| Playbook Interactive Ltd | Information & communication | 2026 |
| Playhousecleaners Ltd | Other services | 2024 |
| Porphyrogenitus Limited | Mining & quarrying | 1987 |
| Portico Consultancy Services Limited | Professional & scientific | 2019 |
| Portlock Mews (Maidenhead) Freehold Limited | Households | 2021 |
| Portlock Mews Management Company Limited | Households | 2015 |
| Powlson and Mcrae Limited | Hospitality | 2023 |
| Prada Investments Limited | Information & communication | 2016 |
| PRC360 Holdings Limited | Administrative & support | 2017 |
| Precieux Jewellers PVT Ltd | Wholesale & retail | 2023 |
| Precision Deer Management UK Ltd | Agriculture & fishing | 2025 |
| Primary Construction Ltd | Construction | 2014 |
| Primary Installations Ltd | Other services | 2017 |
| Primis Consulting Ltd | Information & communication | 2015 |
| Prism Catering Equipment Solutions Ltd | Manufacturing | 2022 |
| Proinso UK Limited | Wholesale & retail | 2011 |
| Project Property Investments Limited | Real estate | 2020 |
| Property Campus Ltd | Education | 2023 |
| Property Parents Limited | Real estate | 2019 |
| Protech Broadcast Facilities Limited | Information & communication | 1991 |
| PSD Solutions Ltd. | Administrative & support | 2007 |
| Pucci's Dog Boutique Ltd | Wholesale & retail | 2021 |
| Punto Padel Ltd | Hospitality | 2026 |
| Purexml Limited | Information & communication | 2011 |
| Purified Water Services Limited | Water & waste | 2011 |
| Pwr-Fx Ltd | Construction | 2020 |
| Pyegrove Chase Management Company Limited | Households | 1989 |
| Pyramid Environmental Services Limited | Administrative & support | 1981 |
| Qogori Europe Ltd | Manufacturing | 2023 |
| Qsuk Limited | Professional & scientific | 2004 |
| Quantum Analytica Ltd | Information & communication | 2018 |
| Queenshill Lodge Services Limited | Households | 1992 |
| R a Brown Consultancy Limited | Professional & scientific | 2015 |
| R C Barrett & Co Limited | Professional & scientific | 1998 |
| R W Equity Holdings Limited | Real estate | 2016 |
| R&E Property (Surrey) Ltd | Real estate | 2021 |
| RAD Additive Limited | Information & communication | 2015 |
| RAD Engineering Group Limited | Professional & scientific | 2025 |
| Ranet Development Limited | Information & communication | 2022 |
| Ranet Lettings Limited | Real estate | 2024 |
| RAW Plumbing and Heating Ltd | Construction | 2015 |
| Rawlings Investments LLP | | 2021 |
| Rawlings of Cranleigh Limited | Wholesale & retail | 2002 |
| Re-Tribe Collective Limited | Extraterritorial | 2026 |