| ORU Technology Consulting Limited | Professional & scientific | 2023 |
| Orwin Property Ltd | Real estate | 2022 |
| Oryx Technology Limited | Information & communication | 2017 |
| Osborne and Co (Warrington) Limited | Construction | 1928 |
| Osborne Young Holdings Limited | Construction | 2013 |
| OSC Consulting Limited | Professional & scientific | 2019 |
| Oscar Inspired Ltd | Other services | 2012 |
| Oscar Tango Solutions Limited | Transport & logistics | 2016 |
| Oshema Consultancy Limited | Professional & scientific | 2017 |
| Oskos Rail Limited | Manufacturing | 2026 |
| OSL8 Ltd | Professional & scientific | 2025 |
| Osnath Works Nursery Limited | Health & social care | 2019 |
| OSP Logistics Ltd | Transport & logistics | 2018 |
| Osprey Capital Limited | Professional & scientific | 2008 |
| Osprey Heating Services Limited | Construction | 2014 |
| Osprey Quay Management Services Company Limited | Administrative & support | 2015 |
| Ossian Living Limited | Construction | 2019 |
| Osso Codes Ltd | Wholesale & retail | 2024 |
| Otejiri Solutions Limited | Professional & scientific | 2018 |
| Otistadiwa Ltd | Health & social care | 2014 |
| Otrp Ltd | Real estate | 2025 |
| Otter Publications Limited | Administrative & support | 2012 |
| Otter Rock Limited | Health & social care | 2012 |
| Oulevay Limited | Information & communication | 2018 |
| OUR Back Yard Ltd | Agriculture & fishing | 2021 |
| OUR Landscape Designs Limited | Administrative & support | 2013 |
| Outbehaving Ltd | Information & communication | 2025 |
| Outdoor Gear Shop Ltd | Wholesale & retail | 2011 |
| Outlook Homes Limited | Real estate | 1986 |
| Outset Cafe Ltd | Hospitality | 2018 |
| Ovatar Ltd | Information & communication | 2021 |
| Oven Ready Media Ltd | Information & communication | 2009 |
| Over the Wall Estates Limited | Real estate | 2019 |
| Overndale Engineering Limited | Administrative & support | 2011 |
| OVI Developments Limited | Construction | 2019 |
| OVI Group Limited | Construction | 2019 |
| OVI Homes Limited | Construction | 2019 |
| OVI Stoke Crown Works Ltd | Construction | 2019 |
| OVI Stoke Regeneration Ltd | Construction | 2024 |
| Ovidiu & Ionel Transport Ltd | Transport & logistics | 2025 |
| OW Concessions Limited | Hospitality | 2026 |
| Owen Jeffrey Properties Limited | Real estate | 2023 |
| Owen Oakley Property Ltd | Real estate | 2024 |
| Owen Property Lets Limited | Real estate | 2023 |
| Owen Property Lets NW Limited | Real estate | 2024 |
| Owenplant Ltd | Other services | 2018 |
| Owens Interiors Limited | Professional & scientific | 2024 |
| Oxford Court Freehold Limited | Real estate | 2026 |
| Oxford Manpower Limited | Construction | 2014 |
| Oxley Hough Consulting Limited | Professional & scientific | 2017 |
| OXO Global Ltd | Wholesale & retail | 2025 |
| Oxonfield Ltd | Professional & scientific | 2024 |
| Oxpm Ltd | Professional & scientific | 2023 |
| Ozonefitness Ltd | Administrative & support | 2023 |
| O’Day Properties Ltd | Real estate | 2026 |
| P & B Rentals Limited | Real estate | 2022 |
| P & G Enterprises Limited | Manufacturing | 2014 |
| P & G Packaging Limited | Manufacturing | 1997 |
| P & H Group Holdings Limited | Construction | 2020 |
| P & H Pipelines & Services Limited | Construction | 1987 |
| P & L Developments (Cheshire) Ltd | Real estate | 2021 |
| P & S Driver Services Ltd | Transport & logistics | 2019 |
| P a B Management Limited | Administrative & support | 2015 |
| P B Engineering & Surveying Limited | Administrative & support | 2007 |
| P B Quality Management Solutions Limited | Professional & scientific | 2017 |
| P B Tyres (Golborne) Limited | Wholesale & retail | 2010 |
| P B Tyres Commercial Limited | Wholesale & retail | 2023 |
| P B Tyres Holdings Limited | Financial services | 2023 |
| P D Diesel Ltd | Wholesale & retail | 2007 |
| P G Dental Limited | Health & social care | 2026 |
| P Hailstone Ltd | Information & communication | 2018 |
| P Hallstrom Limited | Administrative & support | 2007 |
| P Houghton Consultancy Limited | Administrative & support | 2024 |
| P J Decorating Ltd | Construction | 2025 |
| P J Walker Consulting Ltd | Administrative & support | 2012 |
| P Johnson Property Management Limited | Households | 2014 |
| P Jones Opex & Management Consultancy Limited | Administrative & support | 2025 |
| P K B (Property Investments) Limited | Real estate | 2007 |
| P K David Ltd | Professional & scientific | 2021 |
| P K Decor Ltd | Construction | 2026 |
| P L Transport Services Limited | Transport & logistics | 2020 |
| P Lister Marine Services Ltd | Manufacturing | 2025 |
| P Mckenna Electrical Ltd | Construction | 2025 |
| P Merrick Consultancy Limited | Professional & scientific | 2018 |
| P REW Consulting Limited | Administrative & support | 2013 |
| P Spurling Joinery Limited | Construction | 2010 |
| P T Developments Ltd | Construction | 2019 |
| P Walker Technical Services Limited | Professional & scientific | 2019 |
| P&A Capital Ltd | Financial services | 2021 |
| P&A NW Ltd | Real estate | 2018 |
| P&A Toys Ltd | Wholesale & retail | 2026 |
| P&C Holdings Limited | Professional & scientific | 2016 |
| P&H Premier Developments Limited | Real estate | 2025 |
| P&M Engineering Consultants Ltd. | Professional & scientific | 2024 |
| P&P Legacy Limited | Real estate | 2021 |
| P&R Professional Services Limited | Real estate | 2019 |
| P&S Smith Property Limited | Real estate | 2025 |
| P'Trix Transport Ltd | Administrative & support | 2025 |
| P. Cosgrove Civil Engineering Ltd. | Construction | 1998 |
| P. J. Eastburn Investments & Developments Limited | Professional & scientific | 1988 |