| NP Aerospace Limited | Manufacturing | 1997 |
| Nscz Ltd | Wholesale & retail | 2025 |
| NSP International Limited | Wholesale & retail | 2023 |
| Nswe Sports Limited | Real estate | 2006 |
| Ntdt Ltd | Information & communication | 2023 |
| Nubis Limited | Administrative & support | 2004 |
| Nurton Developments (Lutterworth) Limited | Real estate | 2023 |
| Nylacast (Trustees) Limited | Manufacturing | 2006 |
| Nylacast Holdings Limited | Manufacturing | 2006 |
| Nylacast Limited | Manufacturing | 2006 |
| Nylacast Overseas Holdings Limited | Manufacturing | 2006 |
| O & P. Fashions Limited | Wholesale & retail | 1987 |
| O'Brien Services (U.K.) Ltd | Construction | 2006 |
| O'Connells Florists & Fruiterers Limited | Wholesale & retail | 2003 |
| O. Hines Limited | Hospitality | 2010 |
| O. L. (Realisations) Limited | | 1987 |
| O.K. Kleening Limited | Administrative & support | 2005 |
| O.P.L. Construction Limited | Construction | 1998 |
| Oak Embroiderers Limited | Wholesale & retail | 2003 |
| Oak Tree International Limited | Extraterritorial | 2008 |
| Oakhall Developments Limited | Construction | 2000 |
| Oakham Design Limited | Other services | 2005 |
| Oakridge Investments Limited | Real estate | 2004 |
| Oaktree Engineering Limited | Manufacturing | 2000 |
| Oakwells Development Limited | Construction | 2023 |
| OB Holdings Limited | Professional & scientific | 2003 |
| Obsan Limited | Real estate | 1986 |
| Ocean Energy and Resource Limited | Professional & scientific | 2003 |
| Ocean Synergy Limited | Administrative & support | 2003 |
| Office & Project Support Limited | Administrative & support | 2004 |
| Officeworx Backoffice-Solutions Limited | Administrative & support | 2004 |
| OK Finance Limited | Professional & scientific | 1997 |
| Okokalu Co Ltd | Health & social care | 2007 |
| Old Park Engineering Services Limited | Construction | 1998 |
| Oldfield Residential Care Ltd | Health & social care | 2003 |
| Oldswinford Enterprises Limited | Hospitality | 1992 |
| Omega Pistons Limited | Manufacturing | 1973 |
| ON the Spot Limited | Wholesale & retail | 2007 |
| On-Site Fabrications Limited | Construction | 2003 |
| ON2NET (UK) Limited | Information & communication | 2000 |
| One Stop Fitness Ltd | Health & social care | 2021 |
| One-Four-Two-Seven Management Limited | Real estate | 2000 |
| Onecall Plumbing & Heating Limited | Construction | 2004 |
| Onexis Limited | Information & communication | 2003 |
| Onsite Central Limited | Other services | 1992 |
| Onsite Specialist Maintenance Limited | Extraterritorial | 1996 |
| Oobran Limited | Wholesale & retail | 2023 |
| Oozells Trading Limited | Arts & recreation | 1995 |
| Optima Wirtschaftsberatung Limited | Administrative & support | 2005 |
| Optimizo Ltd | Information & communication | 2023 |
| Orange & Grey Limited | Professional & scientific | 2004 |
| Organisation for Sickle Cell Anaemia Research (Oscar) Sandwell Company Limited | Information & communication | 1999 |
| Original Stem Cell Life Technology Co., Limited | Manufacturing | 2026 |
| Orthoplan Limited | Health & social care | 1990 |
| Otis Vehicle Rentals Limited | Wholesale & retail | 1996 |
| Outlaw Auto Repairs Ltd | Wholesale & retail | 2025 |
| O`Flanagan Homes Limited | Construction | 2006 |
| P & M Components (U.K.) Limited | Manufacturing | 1987 |
| P Bunce Industrial Roofing & Cladding Limited | Construction | 2005 |
| P H S Consultants Limited | Wholesale & retail | 1998 |
| P T N Estates Ltd | Real estate | 2003 |
| P. P. Finishers Ltd | Manufacturing | 1995 |
| P.A. Watts Engineering Limited | Professional & scientific | 2004 |
| P.B.M. Components Limited | Professional & scientific | 1924 |
| P.J. Barnett Consultants Limited | Construction | 1972 |
| P.Pantelis & Co Ltd | Manufacturing | 2024 |
| Pakeman Investments (Walsall) Limited | Construction | 1965 |
| PAL Group (Operations) Limited | Manufacturing | 1980 |
| Pamma and Rakhra Associated Limited | Professional & scientific | 2004 |
| Papas (UK) Limited | Hospitality | 2004 |
| Paradise Adventure Park Limited | Arts & recreation | 2008 |
| Paragon Analysis Limited | Wholesale & retail | 1997 |
| Paramount Securities Limited | Real estate | 2003 |
| Park Engineering Company(Wolverhampton)Limited(The) | Manufacturing | 1940 |
| Parker Contract Services Limited | Construction | 2007 |
| Parkes & Co Accountants Limited | Professional & scientific | 2004 |
| Parkes Galvanizing Limited | Extraterritorial | 1983 |
| Parkfield Management Company Limited | Households | 1981 |
| Parmar Couriers Ltd | Transport & logistics | 2021 |
| Partex Leisurewear Limited | Manufacturing | 2002 |
| Partons Building Supplies Limited | Administrative & support | 2001 |
| Partrak | Professional & scientific | 1939 |
| Partscomm Limited | Wholesale & retail | 1963 |
| Patience Investment Limited | Administrative & support | 2005 |
| Patrick Leather Company Limited | Wholesale & retail | 2003 |
| Paubuk Studios Limited | Information & communication | 2015 |
| Paul Sharpe Limited | Health & social care | 2005 |
| Paul Smith (Keep IT Clean) Limited | Wholesale & retail | 2005 |
| Paulton (Elder) Limited | Real estate | 2019 |
| Pavash Limited | Manufacturing | 2002 |
| PC2000 (UK) Limited | Wholesale & retail | 1998 |
| Pces Limited | Wholesale & retail | 1983 |
| PDB Mechanical Engineering Services Limited | Manufacturing | 2003 |
| PDR (Midlands) Limited | Wholesale & retail | 2002 |
| Peak Performance (Central) Limited | Financial services | 2006 |
| Peals Limited | Professional & scientific | 2002 |
| Pearce Design Limited | Construction | 2008 |
| Peer Developments Limited | Construction | 2005 |
| Pelco Holdings Limited | Real estate | 1998 |
| Penn Models Limited | Wholesale & retail | 2002 |