| Olympian Security Services Limited | Administrative & support | 1998 |
| Ombersley Golf Club Limited | Arts & recreation | 1997 |
| Omney Gardens Management Co Ltd | Households | 2021 |
| Omni Padel UK Limited | Arts & recreation | 2025 |
| On-Mark Consulting Limited | Wholesale & retail | 2020 |
| Onamission Ltd | Wholesale & retail | 2020 |
| One Last Bite Food Co. Ltd | Wholesale & retail | 2024 |
| Oneblueleaf Ltd | Professional & scientific | 2024 |
| Onecs Ltd | Real estate | 2024 |
| Onevalet Ltd | Administrative & support | 2023 |
| Online Boxing Education Limited | Other services | 2026 |
| Optimised Exits Limited | Extraterritorial | 2013 |
| Optimum Workforce (UK) Ltd | Wholesale & retail | 2018 |
| OR Accountancy LLP | | 2016 |
| OR Corporate Solutions LLP | | 2009 |
| Oracle Build Group Limited | Construction | 2025 |
| Orbis Consultancy Solutions Ltd | Professional & scientific | 2020 |
| Orchard Commercial Property Ltd | Real estate | 2021 |
| Orchard JV Limited | Extraterritorial | 2014 |
| Orchard Lettings (Worcestershire) Limited | Real estate | 2017 |
| Orcini Associates LLP | | 2019 |
| Orcini Estates Ltd | Administrative & support | 2019 |
| Orcini Investments Ltd | Financial services | 2019 |
| Organised by Della Limited | Administrative & support | 2024 |
| Orientation Ltd. | Real estate | 1995 |
| Origin Martial Arts Limited | Wholesale & retail | 1995 |
| Orium Design Limited | Professional & scientific | 2012 |
| Ormerod Rutter (N.I.) Limited | Administrative & support | 2019 |
| Ormerod Rutter Corporate Finance Limited | Administrative & support | 2013 |
| Ormerod Rutter Corporate Solutions Limited | Professional & scientific | 2003 |
| Ormerod Rutter Fung LLP | | 2018 |
| Ormerod Rutter Holdings Limited | Professional & scientific | 2002 |
| Ormerod Rutter Limited | Professional & scientific | 2002 |
| Ormerod Rutter Private Client Services Limited | Administrative & support | 1999 |
| Ormerod Rutter Solutions Limited | Administrative & support | 1999 |
| Orthopaedic and Trauma Specialists Indemnity Scheme Ltd | Professional & scientific | 2011 |
| Osaka (High Wycombe) Limited | Hospitality | 2022 |
| Osaka (London) Limited | Hospitality | 2023 |
| Osaka (Reading) Limited | Hospitality | 2019 |
| Oscar Trading Limited | Professional & scientific | 2013 |
| Ostermann UK Limited | Manufacturing | 2010 |
| Ostlers Meadow Residents Limited | Households | 1998 |
| Otley Medical Services Ltd | Health & social care | 2026 |
| Outdoor Hands Ltd | Other services | 2013 |
| Owen Racing Organisation Limited | Administrative & support | 2020 |
| Ownerous Ltd | Administrative & support | 2019 |
| Oxford Gynaecology LLP | | 2026 |
| O’Connell Care Group Limited | Health & social care | 2023 |
| P F C Healthcare Ltd. | Professional & scientific | 1929 |
| P M Commercials Limited | Wholesale & retail | 2002 |
| P M L Project Consultancy Limited | Administrative & support | 2013 |
| P N Brothers Limited | Hospitality | 2025 |
| P R Tool Supplies Ltd. | Wholesale & retail | 2006 |
| P Tech Property Limited | Real estate | 2025 |
| P.R.F. Consultancy Limited | Health & social care | 2020 |
| P.S.B. Industrial Services Limited | Professional & scientific | 2021 |
| Paddock Lane Automotive Limited | Wholesale & retail | 2026 |
| PAG37 Consulting Ltd | Professional & scientific | 2025 |
| Paint Tech (UK) Limited | Wholesale & retail | 2008 |
| Pakawaste Engineering Services Limited | Manufacturing | 1990 |
| Pakawaste Holdings Limited | Financial services | 1998 |
| Paladin Experts Limited | Professional & scientific | 2022 |
| Paladin Financial Consultancy Limited | Professional & scientific | 2022 |
| Paladin Group Limited | Financial services | 2022 |
| Panda Droitwich Limited | Hospitality | 2018 |
| Panda-Education Limited | Information & communication | 2013 |
| Paradigm Risk Management Ltd | Professional & scientific | 2020 |
| Paragon Grey Ventures Limited | Professional & scientific | 2018 |
| Parami Medical Consulting Ltd | Health & social care | 2020 |
| Park Grove Avenue Ltd | Financial services | 2018 |
| Parkfields Management (Oddingley) Limited | Households | 1995 |
| Parks & Estate Management Limited | Real estate | 2025 |
| Parks Cafe Droitwich Ltd | Hospitality | 2021 |
| Parotia Properties Limited | Real estate | 2019 |
| Passant Consultancy Services Limited | Professional & scientific | 2017 |
| Patrick Harvey Marketing Ltd | Professional & scientific | 2024 |
| Paul Jackson Carpentry Contractors Ltd | Manufacturing | 2021 |
| Paul Masters Properties Ltd | Real estate | 2024 |
| Pavtec Limited | Administrative & support | 2009 |
| PBM Real Estate Consultancy Ltd | Real estate | 2024 |
| PC Matthews Solutions Limited | Information & communication | 2006 |
| PCM Business Consulting Services Limited | Professional & scientific | 2003 |
| PCS Consulting Engineers Limited | Professional & scientific | 2005 |
| PD Miller Ltd | Transport & logistics | 2021 |
| Pdmn Security Limited | Professional & scientific | 2014 |
| PE Focus Limited | Education | 2023 |
| Peach Projects Limited | Administrative & support | 2021 |
| Pear Tree Construction (Midlands) Limited | Construction | 2003 |
| Pearce Family Properties Limited | Real estate | 2025 |
| Pearl Dental Ceramics Limited | Administrative & support | 2013 |
| Pearpiers Ltd | Financial services | 2021 |
| Peas in a POD Limited | Administrative & support | 2011 |
| Pedley Investment Properties Ltd | Real estate | 2018 |
| Pegasus Financing Limited | Administrative & support | 2021 |
| Pegasus Skip Hire Ltd | Administrative & support | 2018 |
| Pegasus Traffic Management Ltd | Transport & logistics | 2021 |
| Pegasus Utilities Limited | Administrative & support | 2018 |
| Peko Properties LLP | | 2025 |
| Pendersons Products Limited | Manufacturing | 2016 |
| Pension-Able Limited | Administrative & support | 2013 |