| NK UK Management Ltd | Real estate | 2025 |
| NM Marketing Ltd | Real estate | 2014 |
| NNN Management Limited | Real estate | 2024 |
| NO 1 Pentire Newquay Ltd | Real estate | 2021 |
| Noble Computers Limited | Professional & scientific | 1992 |
| NOC Services Limited | Administrative & support | 2006 |
| Northern Lites Limited | | 1986 |
| Novis IT Solutions Ltd | Information & communication | 2026 |
| Novo Enterprises Ltd | Professional & scientific | 2011 |
| Oak Leigh Court Block 'B' RTM Company Limited | Real estate | 2003 |
| Oak Park Developments Limited | Real estate | 2007 |
| Oak Tree Properties Investments Limited | Real estate | 2004 |
| Oaklands Information Systems Limited | Information & communication | 2007 |
| Oakley Properties (UK) Limited | Real estate | 1989 |
| Observer Security Services Limited | Arts & recreation | 1992 |
| OJH Limited | Real estate | 2005 |
| Old and Wise Productions Limited | Professional & scientific | 2005 |
| Old Town Rentals Ltd | Real estate | 2015 |
| Oldcastle Books Limited | Information & communication | 1983 |
| Oliver & Cooksey Limited | Construction | 1964 |
| Oliver Elliot Limited | Professional & scientific | 2019 |
| Omni - Financial Ltd | Financial services | 2005 |
| Opes International Limited | Wholesale & retail | 2004 |
| Optim Toys Limited | | 1978 |
| Option Property Services Limited | Real estate | 2005 |
| OR Consulting Engineers Limited | Professional & scientific | 2006 |
| Oratorio Limited | Information & communication | 1987 |
| Orchard Physiotherapy Clinic Limited | Health & social care | 2003 |
| Orion Holdings (UK) Limited | Financial services | 2013 |
| Orop Healthcare Services Ltd | Health & social care | 2006 |
| Oscars Pizza Company Limited | Hospitality | 1996 |
| OUT of Office Solutions Ltd | Real estate | 2017 |
| Own Homes Limited | Real estate | 2007 |
| P & D Investigations Limited | Administrative & support | 2002 |
| P & D P | | 1985 |
| P and R Consultancy Ltd | Other services | 2023 |
| P C Harding Limited | Other services | 2002 |
| P R Farming Limited | Agriculture & fishing | 2006 |
| P.Brant and Sons Limited | Manufacturing | 1959 |
| P.Oldham Prime Foods Limited | | 1972 |
| Pacebrow.Com Ltd | Construction | 2005 |
| Padco Engineering Limited | Manufacturing | 2007 |
| Page and Page Limited | Professional & scientific | 2016 |
| Pagesoft Systems Limited | Information & communication | 1995 |
| Palmhall Limited | Hospitality | 1981 |
| Pamplad Limited | | 1976 |
| Parkwood Properties Limited | Construction | 1980 |
| Paul Harrison Consultancy Limited | Information & communication | 2007 |
| Payling Mcdonald Limited | Information & communication | 2006 |
| PCB Piezotronics Limited | Administrative & support | 2006 |
| Pego ITR | | 1995 |
| People Diligence Ltd | Professional & scientific | 2010 |
| Peridot Medical Ltd | Education | 2024 |
| Peter Lynn (Wallpapers) Limited | | 1968 |
| Photographers Business Academy Limited | Professional & scientific | 2019 |
| Pieria UK Ltd | Hospitality | 2025 |
| Pilotbase Limited | Real estate | 2005 |
| Piperdale Limited | Wholesale & retail | 2008 |
| Piranha Graphics Limited | Information & communication | 1982 |
| Pitshanger Village Bakery Ltd | Wholesale & retail | 2022 |
| PJC Electrical Services South East Ltd | Construction | 2004 |
| PJF Telecoms Limited | Professional & scientific | 2015 |
| Plus Catering Ltd | Hospitality | 2019 |
| Poachers Tavern Ltd | Hospitality | 2006 |
| Poundhouse Properties Limited | Real estate | 1998 |
| Pptm Properties Limited | Construction | 1996 |
| Prae Close Estates Management Limited | Households | 1987 |
| Premier Contracts (Welwyn) Limited | Construction | 2004 |
| Premier Drainage Services (UK) Limited | Water & waste | 2007 |
| Premier Freight Services (Clacton-On-Sea) Limited | Information & communication | 1977 |
| President Public Houses Limited | | 1991 |
| Price Bailey Group Limited | Financial services | 2002 |
| PRN Property Support Ltd | Real estate | 2007 |
| Productive Forestry Limited | | 1963 |
| Professional Capture Ltd | Professional & scientific | 2006 |
| Professional Structural Services Limited | Professional & scientific | 1991 |
| Proframer Ltd | Arts & recreation | 2023 |
| Projekt QS (Group) Ltd | Professional & scientific | 2024 |
| Propax Limited | Construction | 2005 |
| Properties @ George's Limited | Real estate | 2020 |
| Property Team 55 UK Limited | Real estate | 2016 |
| Pryor Construction Limited | Construction | 2002 |
| PSA Solutions Limited | Construction | 2006 |
| PYM Solutions Limited | Professional & scientific | 2007 |
| QHF Industrial Investments Ltd | Real estate | 2020 |
| QI Kwan DO Ltd | Arts & recreation | 2004 |
| QSH Limited | Information & communication | 2005 |
| Qualistead Ltd | Professional & scientific | 2007 |
| Quantum Experts (London) Ltd | Professional & scientific | 2021 |
| Quantum Experts (Partnership) Ltd | Professional & scientific | 2016 |
| Queenswood School Limited | Education | 1894 |
| Quick Search Direct Limited | Administrative & support | 2010 |
| Quin-Essence Limited | Professional & scientific | 2004 |
| R O Ventures Limited | Professional & scientific | 1963 |
| R. Sitton and Sons Limited | | 1980 |
| Race Concepts UK Limited | Wholesale & retail | 2019 |
| Radiant Heating International Limited | | 1984 |
| Radlett Lawn Tennis Club Limited | Arts & recreation | 1960 |
| Ramar 1992 Limited | Professional & scientific | 1995 |
| Ramblers Travel Agency Limited | Administrative & support | 1961 |