| Nini London Ltd | Professional & scientific | 2020 |
| Niranja Convenience Store Ltd | Wholesale & retail | 2017 |
| NNP Limited | Hospitality | 2019 |
| Noble Developments Limited | Administrative & support | 1994 |
| Nobori Limited | Financial services | 2024 |
| Norton-Simmons Ltd | Real estate | 2021 |
| Novatech Recruitment Ltd | Administrative & support | 2025 |
| Novic Property Holdings Limited | Professional & scientific | 2023 |
| Novic Property Limited | Real estate | 2021 |
| NS Pilates Ltd | Arts & recreation | 2024 |
| Nubuck Works Ltd | Wholesale & retail | 2024 |
| Nutripath Ltd | Health & social care | 2021 |
| NYK Logistics Ltd | Transport & logistics | 2016 |
| NYK Music Limited | Education | 2019 |
| NYK Truckwash Ltd | Administrative & support | 2025 |
| O.B.A. Associates Limited | Construction | 1998 |
| O.K. Events Limited | Administrative & support | 2026 |
| O2 Associates Limited | Financial services | 2002 |
| Oakdene Plumbing Limited | Construction | 2008 |
| Oaklands (Chislehurst) Management Limited | Households | 1999 |
| Oakmead Audiology Limited | Health & social care | 2015 |
| Oberon Developments Limited | Construction | 2014 |
| Oberon Prime LLP | | 2016 |
| Octagon Business Finance Limited | Financial services | 2010 |
| OD Diamonds Limited | Other services | 2025 |
| Odikum Limited | Health & social care | 2004 |
| Odysseia Ltd | Transport & logistics | 2018 |
| Offtman & Co Ltd | Administrative & support | 2019 |
| OJG Telecoms Consulting Ltd | Information & communication | 2019 |
| OKA Behaviour Ltd | Education | 2021 |
| OLE Group Limited | Financial services | 2026 |
| OLE Kyiv Catering Ltd | Hospitality | 2024 |
| OLE UA Ltd | Hospitality | 2022 |
| Oliart Design Ltd | Other services | 2023 |
| Omer & Company Accountants Ltd | Professional & scientific | 2019 |
| Omniscape Ltd | Financial services | 2025 |
| Oncologyapp Limited | Health & social care | 2022 |
| One Little Spa Ltd | Other services | 2025 |
| One Power Limited | Energy | 2011 |
| One Tech Consulting Ltd | Professional & scientific | 2021 |
| Onibaba Ltd | Professional & scientific | 2015 |
| Online Trading Courses Limited | Education | 2018 |
| Onyx Building and Landscaping Ltd | Construction | 2022 |
| Openvivo Ltd | Wholesale & retail | 2009 |
| Optimum Acquisitions Limited | Professional & scientific | 2016 |
| Optimum Organisational Development Limited | Professional & scientific | 2013 |
| Option Care Ltd | Health & social care | 2015 |
| Orion Education | Education | 2011 |
| Ornithology Bars & Restaurants Ltd | Hospitality | 2025 |
| Orpington Football Club | Arts & recreation | 2020 |
| Osnova Consulting Ltd | Administrative & support | 2019 |
| Otek Limited | Wholesale & retail | 2013 |
| Otthon Homes CIC | Real estate | 2025 |
| OUT of Hours Collective Limited | Manufacturing | 2026 |
| Overstone Services Limited | Other services | 2007 |
| Owebello Medical Ltd | Health & social care | 2022 |
| Oxford Signet Ring Company Limited | Wholesale & retail | 2017 |
| Oxus Build Ltd | Construction | 2022 |
| Oxus Consult Ltd | Professional & scientific | 2024 |
| P a Mechanical Limited | Construction | 2016 |
| P F Training Ltd | Education | 2006 |
| P&T Advertising Ltd | Professional & scientific | 2025 |
| Pace Padel Perth Ltd | Arts & recreation | 2026 |
| Paintersdecoratorslondon Ltd | Construction | 2026 |
| Palace Fire and Electric Ltd | Construction | 2024 |
| Paradigm Shelter Ltd | Construction | 2024 |
| Parallel Plumbing Solutions Ltd | Construction | 2022 |
| Parfaire (Chislehurst) Limited | Other services | 2013 |
| Park Mews Chislehurst Limited | Households | 1992 |
| Parkbury Electrical Contractors Ltd | Construction | 2024 |
| Parked Services Ltd | Administrative & support | 2026 |
| Parran Limited | Real estate | 2020 |
| Patton Mathews & Dobbs Limited | Other services | 2008 |
| Paul Long Consultancy Limited | Information & communication | 2018 |
| Pauls News Limited | Wholesale & retail | 2026 |
| PAX Associates Limited | Administrative & support | 2010 |
| Payments for Business Ltd | Professional & scientific | 2022 |
| PB Property & Investments Limited | Real estate | 2010 |
| PCM Technical Services Limited | Professional & scientific | 2012 |
| PDG Interiors Ltd | Construction | 2019 |
| Peckham SE15 Limited | Wholesale & retail | 2021 |
| Peills Courtyard Ltd | Construction | 2025 |
| Pelvicare Ltd | Health & social care | 2022 |
| Pembe Limited | Hospitality | 2026 |
| Penelope Shaw Ltd | Professional & scientific | 2020 |
| Penelope’S Kitchen Ltd | Hospitality | 2026 |
| Penycae Solar Farm Limited | Energy | 2015 |
| Peoplevantage Limited | Administrative & support | 2025 |
| Perceive Finance Transformation Limited | Information & communication | 2024 |
| Percy Contracts Ltd | Construction | 2025 |
| Perla House Group Ltd | Construction | 2026 |
| Perobatesa Ltd | Professional & scientific | 2021 |
| Pet Healthpoint Technologies Limited | Administrative & support | 2012 |
| Pet Savers Limited | Financial services | 2018 |
| Petual IO Ltd | Real estate | 2015 |
| Phace Limited | Information & communication | 2009 |
| Phagre Real Estate Ltd. | Real estate | 2019 |
| Phoenix Fireplaces Kent Ltd | Construction | 2024 |
| Phoenix R2R Ltd | Hospitality | 2024 |
| Phortizo Consulting Ltd | Information & communication | 2007 |