| Novotech Consulting Ltd | Information & communication | 2023 |
| Novus Services Limited | Real estate | 2012 |
| NOW Creations Ltd | Wholesale & retail | 2024 |
| NPS Rugby Limited | Administrative & support | 2025 |
| Nushore Capital Ltd | Financial services | 2022 |
| Nutcombe Cambridge Limited | Construction | 2009 |
| Nutley Ventures Limited | Professional & scientific | 2021 |
| Nutrilans Ltd | Administrative & support | 2016 |
| Nylon Search Limited | Administrative & support | 2014 |
| Oakley Brickwork Ltd | Construction | 2015 |
| Oakley Project Management Ltd | Professional & scientific | 2009 |
| Oakwood Training & Consultancy Ltd | Education | 2017 |
| Oasis Project Management Limited | Other services | 2004 |
| Occult Print Shop Ltd | Wholesale & retail | 2023 |
| Ocean Blue OB Ltd | Other services | 2026 |
| Octavia Marketing Limited | Information & communication | 2007 |
| OFF Developments Limited | Real estate | 2003 |
| OJ Property Sourcing & Development Ltd | Real estate | 2019 |
| Okapi Worldwide Ltd | Professional & scientific | 2025 |
| OL Power Ltd | Mining & quarrying | 2022 |
| Old Mill Consulting Services Limited | Professional & scientific | 2011 |
| Old School Walk (Church Langton) Management Company Limited | Real estate | 2006 |
| Olivant Consulting Limited | Professional & scientific | 2008 |
| OMG Engineering Ltd | Professional & scientific | 2025 |
| Omni Management Solutions Ltd | Professional & scientific | 2019 |
| Omni MEP Project Management Ltd | Construction | 2025 |
| ON Demand Digital Print Ltd | Manufacturing | 2010 |
| ON the Path Fashions Ltd | Wholesale & retail | 2023 |
| One Lifestyle Limited | Arts & recreation | 2002 |
| Onifot Ltd | Wholesale & retail | 2021 |
| Ontrack Apps Limited | Information & communication | 2016 |
| Ontrack Couriers Limited | Transport & logistics | 2010 |
| Onwards Energy Ltd | Professional & scientific | 2020 |
| Open Construct Limited | Construction | 2020 |
| Opes Diagnostics Limited | Wholesale & retail | 2019 |
| Opex Consultancy Limited | Professional & scientific | 2010 |
| Optimax Imaging, Inspection and Measurement Ltd | Manufacturing | 2005 |
| Orange Juice Communications Limited | Professional & scientific | 2012 |
| Orangeandblue Limited | Information & communication | 2021 |
| Orbit Properties (UK) Limited | Construction | 2007 |
| Ornebhim Ltd | Administrative & support | 2024 |
| Orwell Hospitality Limited | Hospitality | 2024 |
| Oryvo Ltd | Professional & scientific | 2025 |
| Osborne Group Ltd | Professional & scientific | 2018 |
| Ottoman Barbers TR Ltd | Other services | 2019 |
| Overman,Son & Company Limited | Agriculture & fishing | 1962 |
| Oxendon Hall Management Company Limited | Households | 2006 |
| Oxley Medical Limited | Health & social care | 2010 |
| OZO Collective Limited | Administrative & support | 2023 |
| P & D Furniture Limited | Wholesale & retail | 2024 |
| P & K Marvin Limited | Financial services | 2022 |
| P & L Senior Limited | Real estate | 2014 |
| P and V Holdings Ltd | Financial services | 2019 |
| P T M Design Limited | Manufacturing | 2003 |
| P Three Business Development Ltd | Professional & scientific | 2020 |
| P&H Developments (Cornwall) Ltd | Construction | 2012 |
| P.T.M. Limited | Real estate | 1996 |
| P4W Limited | Other services | 2012 |
| P4W MH Ltd | Other services | 2025 |
| PA Support Services Lutterworth Ltd | Health & social care | 2022 |
| Pabari Enterprises Limited | Wholesale & retail | 2003 |
| Pacific Atlantic (UK) Ltd | Administrative & support | 2005 |
| Pacj (UK) Ltd | Real estate | 2020 |
| Packer Consultancy Limited | Administrative & support | 2020 |
| Paddlock Limited | Other services | 2025 |
| Paddock Capital Limited | Financial services | 2024 |
| Padel Shift Ltd | Arts & recreation | 2021 |
| Paget's Place Properties Limited | Real estate | 2025 |
| Pain Enterprises Limited | Real estate | 2007 |
| PAL- Project Services Limited | Professional & scientific | 2008 |
| Palm 16 Holdings Ltd | Financial services | 2026 |
| Palms Customs Ltd | Manufacturing | 2025 |
| Parabox Games Ltd | Wholesale & retail | 2023 |
| Paradigm Interiors Ltd | Construction | 2012 |
| Paramedx Ltd. | Health & social care | 2020 |
| Parker Farms Limited | Extraterritorial | 1961 |
| Parker Green Energy Limited | Energy | 2022 |
| Parker Strategic Holdings Limited | Professional & scientific | 2021 |
| Parker Strategic Land Limited | Professional & scientific | 2016 |
| Parkers of Leicester Limited | Professional & scientific | 1987 |
| Parkhouse Wealth Management Limited | Extraterritorial | 2014 |
| Parr Automotive Ltd | Wholesale & retail | 2010 |
| Partners in Psychology Limited | Education | 2011 |
| Partridge & Sons Limited | Professional & scientific | 1994 |
| Passion Food Events Ltd | Hospitality | 2019 |
| Pathfinder Schools | Education | 2011 |
| Paul Adair Limited | Professional & scientific | 2008 |
| Paul Anthony (Hairdressing) Limited | Other services | 2002 |
| Paul Badger Earthmoving Ltd | Construction | 2016 |
| Paul James Food Technical Consultancy Ltd | Professional & scientific | 2014 |
| Paul Johnson Design Limited | Extraterritorial | 2012 |
| Pawnpig Ltd | Wholesale & retail | 2025 |
| Paws for Adventure Ltd | Other services | 2025 |
| Pawson Tree Care Ltd | Agriculture & fishing | 2022 |
| Paxton Court (Little Paxton) Management Company Limited | Households | 1991 |
| Paynt Limited | Financial services | 2017 |
| PB & ER Developments Limited | Construction | 2025 |
| PDR Services Limited | Wholesale & retail | 2016 |
| Peachwell Limited | Wholesale & retail | 2019 |
| Peartree Home & Garden Ltd | Wholesale & retail | 2025 |