| Onze Atelier Ltd | Wholesale & retail | 2021 |
| Oodle Software Limited | Information & communication | 2026 |
| Oofytech Limited | Manufacturing | 2015 |
| OOH LA LA Activewear Ltd | Wholesale & retail | 2021 |
| Operculum Ltd | Health & social care | 2025 |
| Oppenheimcard Ltd | Information & communication | 2024 |
| Opti Aggregates NW Limited | Administrative & support | 2021 |
| Opticmarket Limited | Wholesale & retail | 1996 |
| Optimedic Ltd | Education | 2024 |
| Optimum Design and Build Ltd | Construction | 2019 |
| Optimum Groundworks NW Limited | Administrative & support | 2019 |
| Options Pundits Trading and Investment Company Ltd | Financial services | 2026 |
| Oral Cosmetic Consulting Ltd | Manufacturing | 2011 |
| Orange Lane Real Estate Limited | Real estate | 2023 |
| Orbit Executive Chauffeurs Ltd | Transport & logistics | 2026 |
| Orbit Motors Ltd | Wholesale & retail | 2026 |
| Orbital Doha Limited | Professional & scientific | 2006 |
| Orbital Eastern Europe Limited | Financial services | 2022 |
| Orbital Education Limited | Professional & scientific | 2008 |
| Orbital Hispania Limited | Financial services | 2025 |
| Orbital Iberia Limited | Financial services | 2023 |
| Organic Coaching Ltd | Education | 2025 |
| Organic Youth Limited | Manufacturing | 2016 |
| Orient Gate Inspection Ltd | Professional & scientific | 2026 |
| Origin Sports Management Ltd | Arts & recreation | 2025 |
| Origym C.I.C. | Other services | 2025 |
| Orion Intelligence Ltd | Administrative & support | 2024 |
| Orixo Interiors Ltd | Other services | 2025 |
| Orme Mansions Management Company Limited | Households | 2004 |
| Orthis Limited | Professional & scientific | 2016 |
| Orthosai Limited | Health & social care | 2023 |
| Osborne and Berry Limited | Wholesale & retail | 2019 |
| Osborne House Wilmslow Management Company Limited | Households | 2003 |
| Oscar Associates (Manchester) Limited | Administrative & support | 2006 |
| Osman Medics 2000 Ltd | Health & social care | 2025 |
| Osman Optics Ltd | Wholesale & retail | 2024 |
| Osprey Motors Ltd | Wholesale & retail | 2023 |
| Oswald Films Ltd | Information & communication | 2018 |
| Otter Sound Limited | Information & communication | 2008 |
| Otto Simon Chemicals Limited | Professional & scientific | 2016 |
| Otto Simon Holdings Limited | Administrative & support | 2008 |
| Otto Simon Limited | Professional & scientific | 2003 |
| Otto Simon Services Limited | Professional & scientific | 2018 |
| OUR Hero Cleaning Solutions Ltd | Administrative & support | 2025 |
| OUT There Healthtech Ltd | Information & communication | 2025 |
| Outer Sight Music Ltd | Manufacturing | 2022 |
| Overlanderx Limited | Wholesale & retail | 2026 |
| Overseas School Placement Limited | Financial services | 2005 |
| Overtec Limited | Information & communication | 2010 |
| Owenty Ltd | Wholesale & retail | 2020 |
| Oxbridge Digital Ltd | Professional & scientific | 2019 |
| Oxbrucle Limited | Professional & scientific | 2018 |
| Oxmit Technologies Limited | Information & communication | 2020 |
| Oypt Limited | Hospitality | 2020 |
| Ozjgrip Limited | Information & communication | 2014 |
| OZTECH3D Limited | Professional & scientific | 2021 |
| P & V Brazendale Properties Ltd | Professional & scientific | 2015 |
| P a Consultants Limited | Extraterritorial | 1996 |
| P and L Barton Holdings Limited | Real estate | 2023 |
| P B Brickwork Solutions Limited | Construction | 2015 |
| P B Property Investments LLP | | 2010 |
| P H (Halecroft) Limited | Construction | 2018 |
| P H Property Holdings Limited | Construction | 1996 |
| P Louise Makeup Academy Ltd | Administrative & support | 2016 |
| P Mannion Limited | Administrative & support | 2007 |
| P R Restaurants Limited | Hospitality | 2006 |
| P.M. Dental Care Ltd | Health & social care | 2010 |
| P5 Property Ltd | Real estate | 2024 |
| Pabale Healthcare Ltd | Health & social care | 2026 |
| Padel Pingpong Limited | Manufacturing | 2025 |
| Padelbeyond UK Ltd | Construction | 2025 |
| Padl Sport Ltd | Wholesale & retail | 2023 |
| Pagos Holdings I Limited | Financial services | 2021 |
| Paid Attention Limited | Professional & scientific | 2025 |
| Pajk Engineering and Consultancy Ltd | Professional & scientific | 2024 |
| Pakistani Resource Centre Limited | Health & social care | 1966 |
| Palm Properties MCR Limited | Real estate | 2026 |
| Palo Learning Ltd | Education | 2022 |
| PAN Energy Limited | Wholesale & retail | 2019 |
| Panacea Holistic Limited | Other services | 2023 |
| Panache Pharma Ltd | Health & social care | 2013 |
| Panda Refrigerants Ltd | Wholesale & retail | 2018 |
| Panorama ICT Ltd | Information & communication | 2014 |
| Pantek Limited | Professional & scientific | 1997 |
| Pantheon Prospects Ltd | Professional & scientific | 2026 |
| Pantiles Catering Ltd | Hospitality | 2026 |
| Papyrus Pharma Ltd | Wholesale & retail | 2025 |
| Paradise Isle Holidays Limited | Administrative & support | 2018 |
| Paramose Limited | Professional & scientific | 1997 |
| Parasence Property Consultancy Limited | Professional & scientific | 2014 |
| PARCELS2U Ltd | Wholesale & retail | 2024 |
| Pargar Properties Ltd | Real estate | 2022 |
| Park & Bark @ Broomstairs Dog Paddock Ltd | Other services | 2026 |
| Park Lane Europe Limited | Real estate | 2005 |
| Park Mews (WR) Management Co. Limited | Households | 2004 |
| Park View (Gatley) Management Company Limited | Real estate | 2004 |
| Parkway Medical Limited | Health & social care | 2021 |
| Pasha Barber Village Ltd | Other services | 2019 |
| Pass Go Property Group Limited | Extraterritorial | 2022 |
| Past & Present Wood Flooring Ltd | Construction | 2021 |