| New Light Property Limited | Construction | 2020 |
| New TAI Tong Limited | Hospitality | 2019 |
| Newnham & SON Ltd | Professional & scientific | 2014 |
| Newtonai Ltd | Information & communication | 2026 |
| Nextgen Pensions Ltd | Professional & scientific | 2020 |
| Nhaigh Holdings Ltd | Financial services | 2025 |
| NHJ Limited | Real estate | 1997 |
| Nicholas Heyworth Properties Ltd | Real estate | 2024 |
| Nichols Hunt Limited | Information & communication | 2014 |
| Nick Heasman Ltd | Professional & scientific | 2026 |
| Nick R Consulting Limited | Professional & scientific | 2024 |
| Nick Troth Private Hire Ltd. | Transport & logistics | 2016 |
| Nightjar Engineering & Construction Ltd | Manufacturing | 2015 |
| Nikara Aesthetics Ltd | Other services | 2025 |
| NIX Computing Ltd | Information & communication | 2012 |
| Nonoise Limited | Extraterritorial | 2004 |
| Normington's Hair Ltd | Other services | 2017 |
| Nova Seven Prime UK Limited | Construction | 2025 |
| Nowhere BOY Productions Limited | Information & communication | 2008 |
| NPG. Electrical Ltd. | Construction | 2023 |
| Npwb & Co Limited | Professional & scientific | 2020 |
| NRC Business Management Services Ltd | Professional & scientific | 2015 |
| NTS Strategy Ltd | Information & communication | 2026 |
| NU & MII Limited | Professional & scientific | 2017 |
| NURSCARE24 Limited | Administrative & support | 2021 |
| Nurtured Learning Limited | Health & social care | 2025 |
| Nutmegs of Petersfield Limited | Construction | 2019 |
| Nyewood Holdings Ltd | Financial services | 2015 |
| Nywave Group Limited | Transport & logistics | 2002 |
| Oak Services Limited | Construction | 1992 |
| Oakden London Ltd | Manufacturing | 2014 |
| Oakdome Limited | Real estate | 2024 |
| Oaklyfe Ltd | Transport & logistics | 2023 |
| Oakmont Southern Ltd | Construction | 2019 |
| Oakview Investment Holdings Ltd | Financial services | 2025 |
| Oberon Consultancy Ltd | Professional & scientific | 2008 |
| Ofcs Limited | Financial services | 2003 |
| OFF Record Events Ltd | Arts & recreation | 2025 |
| OH Consults Limited | Professional & scientific | 2023 |
| Olas Group Ltd | Wholesale & retail | 2020 |
| Old Flames Limited | Wholesale & retail | 1989 |
| Old Parlour Homes Limited | Construction | 2025 |
| OMA Investments Limited | Real estate | 2016 |
| One Danehurst Street Limited | Households | 1983 |
| One Roundhill Crescent Brighton (Residents) Limited | Real estate | 2004 |
| Oneguardianship Limited | Education | 2023 |
| Online Architecture Limited | Professional & scientific | 2022 |
| Onlyfe Ltd | Extraterritorial | 2016 |
| Onverra Ltd | Real estate | 2025 |
| Onvigil Ltd | Professional & scientific | 2015 |
| Openfield Education Ltd | Education | 2025 |
| Orange Pixel Limited | Information & communication | 2015 |
| Orchard Design Ltd | Professional & scientific | 2019 |
| Ordinal Space Ltd | Information & communication | 2015 |
| Orlu Limited | Information & communication | 2016 |
| ORR Construct Ltd | Construction | 2026 |
| Osgood Property Limited | Real estate | 2017 |
| OSY Perfect Cleaning Company Ltd | Administrative & support | 2023 |
| Otic Productions Limited | Information & communication | 2012 |
| Ottershaw Limited | Professional & scientific | 2015 |
| Otto Pictures Ltd | Information & communication | 2025 |
| Outstanders Limited | Administrative & support | 2009 |
| Owens Cycles Limited | Wholesale & retail | 2012 |
| P C Rhodes Limited | Construction | 2014 |
| P M Marsh Limited | Wholesale & retail | 1998 |
| P Takeaway Ltd | Hospitality | 2024 |
| PA1 a Ltd | Construction | 2025 |
| PA2 a Ltd | Construction | 2025 |
| Palmer Press Limited | Information & communication | 2024 |
| Pamela Roberts & Associates Ltd | Health & social care | 2020 |
| Pantha Coffee Ltd | Hospitality | 2024 |
| Parabellum Technology Limited | Professional & scientific | 2023 |
| Paradigm Shift Engineering Ltd | Professional & scientific | 2026 |
| Paradigm Shift Holdings Ltd | Professional & scientific | 2026 |
| Paradise Balti Ltd | Hospitality | 2024 |
| Paragraphs Ltd | Extraterritorial | 2015 |
| Parcelutions Ltd | Transport & logistics | 2014 |
| Park House Hampshire Limited | Households | 2019 |
| Parm Consulting Ltd | Professional & scientific | 2019 |
| Parrotts Holdings Limited | Financial services | 2023 |
| Parrotts Stays Ltd | Professional & scientific | 2024 |
| Passaro Publicity Ltd | Professional & scientific | 2019 |
| Passionate About Care Limited | Health & social care | 2015 |
| Patching Company Ltd | Professional & scientific | 2020 |
| Patriott Ltd | Education | 2025 |
| Paul Crocker Limited | Other services | 2006 |
| Paul J Needham Limited | Construction | 2009 |
| Paul Randall Limited | Construction | 2005 |
| PAW Mates Pet Services Ltd | Agriculture & fishing | 2025 |
| Paypuk Ltd | Manufacturing | 2021 |
| Pdln Limited | Information & communication | 2017 |
| Peachy Living Limited | Households | 2025 |
| Peacock Investments (PVT) Limited | Hospitality | 2021 |
| Peak Power Health Ltd | Wholesale & retail | 2025 |
| Pebble Stone HR Ltd | Administrative & support | 2026 |
| Pekay Limited | Information & communication | 2017 |
| Pelican Blood Films Limited | Information & communication | 2008 |
| Pelican Projects Limited | Professional & scientific | 2002 |
| People Make Places Limited | Information & communication | 2012 |
| Peopleclever Ltd | Administrative & support | 2017 |