| Ooszoo Ltd | Wholesale & retail | 2019 |
| Opalus Ltd | Wholesale & retail | 2019 |
| Openfield Agriculture Limited | Agriculture & fishing | 1998 |
| Openfield Grain Limited | Agriculture & fishing | 1994 |
| Openfield Marketing Limited | Agriculture & fishing | 2002 |
| Openings Direct Limited | Construction | 2006 |
| Ophelia Debt Purchase Limited | Extraterritorial | 2026 |
| Optima Healthcare Solutions Ltd | Administrative & support | 2022 |
| Optima Holidays Ltd | Administrative & support | 2023 |
| Optima-Wg Ltd | Transport & logistics | 2022 |
| Optimum Transport Solutions Limited | Transport & logistics | 2025 |
| OQ Brook Ltd | Transport & logistics | 2021 |
| ORA Motor Services Ltd | Wholesale & retail | 2018 |
| ORA Motorsport Limited | Education | 2026 |
| Oriana Underwriting Limited | Financial services | 2009 |
| Oriole Creative Consulting Ltd | Professional & scientific | 2022 |
| Orme Electrical Limited | Construction | 2008 |
| Oscar Assets Limited | Households | 2022 |
| Oscar IDP Limited | Information & communication | 2024 |
| OUT OUT Ltd | Hospitality | 2021 |
| Outdoor Inspirations Limited | Real estate | 2003 |
| Outsourceful Recruitment Ltd | Administrative & support | 2023 |
| Outwood CIC | Administrative & support | 2018 |
| Ovalfriar Limited | Real estate | 1972 |
| Overghyll LLP | | 2008 |
| P C Building Services (Notts) Ltd | Construction | 2012 |
| P H Bioenergy Limited | Energy | 2014 |
| P MCG Construction Ltd | Construction | 2024 |
| P N & E Odlin Limited | Agriculture & fishing | 2008 |
| P N White Limited | Financial services | 2014 |
| P&B Logistics Ltd | Wholesale & retail | 2015 |
| P&P Commercial Ltd | Real estate | 2013 |
| P. Cottingham & Sons Limited | Agriculture & fishing | 1965 |
| P.D Car Service Ltd | Wholesale & retail | 2013 |
| P.M. Bradley (Farms) Limited | Agriculture & fishing | 1974 |
| PAD Tax Services Limited | Professional & scientific | 2005 |
| Padall Ltd | Wholesale & retail | 2026 |
| Padgett Restorations Ltd | Wholesale & retail | 2024 |
| Paktronic Engineering Company Limited | Manufacturing | 1965 |
| Palace House International (Two) LLP | | 2006 |
| Palm Way 1000 LLP | | 2009 |
| Palm Way Limited | Financial services | 2014 |
| Palma Creator Network Ltd | Professional & scientific | 2025 |
| Pancake Hill Sustainable Woodlands CIC | Agriculture & fishing | 2026 |
| Pancha Time Limited | Wholesale & retail | 2023 |
| Panda Cat Games Ltd | Information & communication | 2024 |
| Paradigm Gym Ltd | Arts & recreation | 2023 |
| Paradigm Training Limited | Professional & scientific | 2005 |
| Paragon Training & Consultancy Ltd | Education | 2017 |
| Parcel MAN Team Ltd | Transport & logistics | 2021 |
| Park House Energy Ltd | Extraterritorial | 2016 |
| Parker Marble & Stone Restoration Ltd | Administrative & support | 2022 |
| Parkes Connections Limited | Professional & scientific | 2012 |
| Parkgate Builders Ltd | Construction | 2014 |
| Parkland Motor Group Ltd | Wholesale & retail | 2019 |
| Parkland Motor Services Ltd | Wholesale & retail | 2020 |
| Parmar Optics Limited | Health & social care | 2025 |
| Parrot Education Ltd | Wholesale & retail | 2024 |
| Parshall Underwriting LLP | | 2009 |
| Part Dart Online Limited | Wholesale & retail | 2025 |
| Partnership for Improvement Limited | Professional & scientific | 2024 |
| Parts Export Limited | Wholesale & retail | 1984 |
| Party Planet Limited | Wholesale & retail | 2024 |
| Parvian LLP | | 2007 |
| Pasture Farm Holdings Limited | Financial services | 2022 |
| Pasture Farm Limited | Professional & scientific | 2013 |
| Pateleys Ltd | Real estate | 2024 |
| Pathways Homes Limited | Real estate | 2022 |
| Patrick & Bodea Constructions Ltd | Construction | 2025 |
| Patrick Mattison Ltd | Hospitality | 2008 |
| Patrina Investments Limited | Construction | 1976 |
| Patts & Co Limited | Financial services | 2023 |
| Paul Blantern Enterprises Ltd | Professional & scientific | 2018 |
| Paul Collingwood Limited | Construction | 2008 |
| Paul Doughty Limited | Construction | 2009 |
| Paul Preston Limited | Construction | 2008 |
| Paul Ross Limited | Professional & scientific | 2006 |
| Paul Swinburn Transport Limited | Transport & logistics | 2020 |
| Pavilion Paving Ltd | Construction | 2024 |
| PAW Choices Ltd | Wholesale & retail | 2026 |
| Pawfect Cleanup Limited | Water & waste | 2025 |
| Pawsh Wash Co Ltd | Administrative & support | 2025 |
| Pawtley Ltd | Wholesale & retail | 2025 |
| Paylink AI Ltd | Extraterritorial | 2025 |
| Paylink Solutions Group Limited | Extraterritorial | 2021 |
| Paylink Solutions Limited | Information & communication | 2023 |
| Payment Check Ltd | Information & communication | 2021 |
| Payplan (IVA) Limited | Financial services | 2009 |
| Payplan Bespoke Solutions Limited | Financial services | 2009 |
| Payplan Group Limited | Financial services | 2021 |
| Payplan Limited | Professional & scientific | 2018 |
| Payplan Partnership Limited | Financial services | 2010 |
| Payplan Solutions Limited | Financial services | 2007 |
| PB Aesthetics Training Academy Ltd | Other services | 2019 |
| PCV Support Services Limited | Transport & logistics | 2024 |
| Peacefields Care Ltd | Health & social care | 2025 |
| Peacock Handmade Limited | Manufacturing | 2019 |
| Peashill Limited | Agriculture & fishing | 2000 |
| Peatling Training & Development Limited | Administrative & support | 1999 |
| Pebbl Leisure Limited | Wholesale & retail | 2024 |