| Orchard House Family Assessment Centre Limited | Health & social care | 2003 |
| Orchard Park Nurseries Ltd | Administrative & support | 2017 |
| Orchard Portman Equestrian LLP | | 2020 |
| Orchard Restaurant (Taunton Racecourse) Limited | Hospitality | 1997 |
| Orchard Rise (Taunton) Management Company Limited | Real estate | 2010 |
| Orchard Rise (Truro) Limited | Households | 2019 |
| Orchard View (Stoke-Sub-Hamdon) Management Company Limited | Households | 2019 |
| Orchard View Management (Newton ST Cyres) Company Limited | Households | 2018 |
| Orchards Estates Somerset Limited | Real estate | 2018 |
| ORD Contracting Ltd | Professional & scientific | 2019 |
| Ordnance Developments UK Ltd | Professional & scientific | 2024 |
| Organic Farm Fayre Ltd. | Professional & scientific | 1998 |
| Organic Herb Trading Ltd | Manufacturing | 1999 |
| Orlis Property Consultants Limited | Real estate | 2014 |
| Ormerod Electrical Ltd | Construction | 2016 |
| Osborn Equine Limited | Agriculture & fishing | 2019 |
| Osborne Farming Ltd | Agriculture & fishing | 2012 |
| Osta Properties Ltd | Real estate | 2022 |
| Ostfest Holding Limited | Professional & scientific | 2010 |
| Oswald Furness Ltd | Financial services | 2024 |
| OTB 2 Limited | Real estate | 2016 |
| Otis Ubaka Music Ltd | Information & communication | 2021 |
| OTP Worldwide Ltd | Wholesale & retail | 2021 |
| Otter (South West) Limited | Construction | 2010 |
| Otter Construct Limited | Construction | 2012 |
| Otter Management Services Ltd | Administrative & support | 2026 |
| Otterail (UK) Ltd | Professional & scientific | 2008 |
| Otterstone Property Ltd | Real estate | 2025 |
| Ottie & George Vets Ltd | Professional & scientific | 2026 |
| Outbuild SW Ltd | Construction | 2022 |
| Outdoor Experience Limited | Wholesale & retail | 1997 |
| Outlier Ventures Management LLP | | 2019 |
| Outlier Ventures Participations Ltd | Administrative & support | 2019 |
| Outlier Ventures Services Limited | Administrative & support | 2020 |
| Outwood Dental Practice LLP | | 2018 |
| Over and Under Limited | Wholesale & retail | 2024 |
| Overmoor Holdings Ltd | Financial services | 2024 |
| Owis (NL) LLP | | 2017 |
| Own Cocoon Limited | Wholesale & retail | 2003 |
| Own Your Throne Limited | Other services | 2021 |
| Oxford City Primary Care Ltd | Health & social care | 2023 |
| Oxleaze Farm Limited | Agriculture & fishing | 2010 |
| Oxon Consulting Ltd | Professional & scientific | 2014 |
| OZ Turkish Barber Limited | Other services | 2021 |
| Ozal Food Ltd | Hospitality | 2025 |
| Ozky 07 Ltd | Hospitality | 2024 |
| P & H Machinery Limited | Wholesale & retail | 2006 |
| P & L Bawden Limited | Construction | 2004 |
| P & N Motor Repairs Ltd | Wholesale & retail | 2012 |
| P & P Auto Group Ltd | Wholesale & retail | 2025 |
| P & P Auto MOT Centre Ltd | Wholesale & retail | 2023 |
| P & P Auto Services Ltd | Wholesale & retail | 2021 |
| P & T Mason Ltd | Financial services | 2024 |
| P Aiken Limited | Financial services | 2015 |
| P E a Landscaping Limited | Administrative & support | 2025 |
| P H Coate & SON Limited | Manufacturing | 2008 |
| P J Carpentry (South West) Ltd | Manufacturing | 2017 |
| P L and D J Ltd | Construction | 2023 |
| P M Slade and SON (Developments) Limited | Real estate | 1993 |
| P M Stores (South West) Ltd | Wholesale & retail | 2020 |
| P M Wall Ltd | Construction | 2007 |
| P Phippen Data Cabling Instalations Limited | Information & communication | 2016 |
| P&D 17 Ltd | Hospitality | 2016 |
| P&P Howlett & SON Farming Limited | Agriculture & fishing | 2009 |
| P&S PUB Ltd | Hospitality | 2009 |
| P. E. Holmes & SON Limited | Agriculture & fishing | 2021 |
| P. M. Slade & SON Limited | Professional & scientific | 1973 |
| P.J. Signs (Taunton) Limited | Administrative & support | 2007 |
| P.S. Global Collective Ltd | Wholesale & retail | 2024 |
| P.T.Services Civil Engineering and Groundworks Limited | Construction | 2014 |
| P.T.Winchester Limited | Wholesale & retail | 1969 |
| PA & CT Barrett Limited | Agriculture & fishing | 2007 |
| PA Banwell Limited | Professional & scientific | 2012 |
| Paces Medical Limited | Health & social care | 2026 |
| Packer Estate Management Ltd | Real estate | 2018 |
| Padbear Limited | Financial services | 2022 |
| Paddocks Farm Products Limited | Wholesale & retail | 2014 |
| Paddox Equestrian Ltd | Information & communication | 2024 |
| Padovani Books Limited | Wholesale & retail | 2003 |
| Paedsplus Ltd | Health & social care | 2018 |
| Paffard Management Services Limited | Real estate | 1987 |
| Paifang Accountants & Tax Advisors (UK) Ltd | Professional & scientific | 2014 |
| Paifang Nominees (UK) Ltd | Administrative & support | 2014 |
| Painswick Property Holdings Ltd | Real estate | 2018 |
| Pairs Essentials Limited | Other services | 2026 |
| Paladin Construction Limited | Construction | 2025 |
| Palmix Concrete Limited | Manufacturing | 2012 |
| Pamfa Sports Limited | Arts & recreation | 2015 |
| Panasj LLP | | 2013 |
| Panayiotou Finance Ltd | Financial services | 2022 |
| Panda 168 Limited | Hospitality | 2024 |
| Panda Rose Ltd | Financial services | 2023 |
| Panology Labs Ltd | Professional & scientific | 2025 |
| Papa DAN Ltd | Real estate | 2025 |
| Parade Solutions Ltd | Professional & scientific | 2023 |
| Paraggarg Limited | Health & social care | 2025 |
| Parallel Care Limited | Extraterritorial | 2019 |
| Parallel Holdings Limited | Real estate | 2016 |
| Parallel Independence Limited | Health & social care | 2014 |
| Paraura Limited | Professional & scientific | 2023 |