| Novafide Finance (Great Britain) Limited | Professional & scientific | 1993 |
| Novashopee Ltd | Wholesale & retail | 2025 |
| Novaskart Ltd | Wholesale & retail | 2025 |
| Novodale Limited | Hospitality | 2001 |
| Novus ERA Global Ltd | Other services | 2026 |
| NOW ECO4 Ltd | Construction | 2025 |
| Noxi Limited | Information & communication | 2023 |
| NP Housing Ltd | Real estate | 2024 |
| NQW Ltd | Financial services | 2020 |
| NRG Estates Ltd | Real estate | 2021 |
| Nuclear Commissioning Consulting Limited | Professional & scientific | 2023 |
| Nutri Phase Life Ltd | Arts & recreation | 2025 |
| Nybrhd Ltd | Information & communication | 2024 |
| Nypy Limited | Information & communication | 2021 |
| O'Brien Brothers Ltd | Construction | 2001 |
| OAP Properties Ltd | Real estate | 2024 |
| Obelisk Sports Limited | Professional & scientific | 2020 |
| OBT Heartstone Properties Ltd | Real estate | 2025 |
| OBU Consulting Ltd | Construction | 2025 |
| Oceangreen Energy Ltd | Construction | 2024 |
| Octica Professional Ltd | Wholesale & retail | 2008 |
| Oddbox Theatre Productions Limited | Real estate | 2014 |
| OE Living Ltd | Real estate | 2025 |
| Offshore Business Formation Ltd | Professional & scientific | 2022 |
| Ohana Investments Ltd | Real estate | 2021 |
| Ohana Trading Limited | Hospitality | 2023 |
| Ohquire Limited | Information & communication | 2023 |
| OI Campers! Ltd | Administrative & support | 2025 |
| Oikon Real Estate Investment Ltd | Real estate | 2021 |
| OKI Europe Limited | Wholesale & retail | 1987 |
| OKI Systems Holdings Co Limited | Professional & scientific | 1990 |
| Okinawa Living Ltd | Professional & scientific | 2022 |
| Olarou UK Limited | Real estate | 2025 |
| Olcasa Investments Ltd | Real estate | 2021 |
| Old Grey Property Investments Ltd | Real estate | 2022 |
| OLI Enterprise Ltd | Hospitality | 2011 |
| Olivly Properties Ltd | Real estate | 2024 |
| Olride Properties Ltd | Real estate | 2021 |
| Olson Properties Ltd | Real estate | 2024 |
| Ombré Beauty Studios Limited | Other services | 2021 |
| Omis Management Ltd | Professional & scientific | 2024 |
| ON Top of Business Ltd | Professional & scientific | 2023 |
| One Dimension Ltd | Real estate | 2017 |
| One Key Property Management Limited | Real estate | 2026 |
| One List Limited | Information & communication | 2018 |
| One Saving Enterprises Ltd | Wholesale & retail | 2026 |
| Onedin Capital Partners 8 Limited | Financial services | 2018 |
| Oneup Mobile Fleetwash Limited | Administrative & support | 2021 |
| Oneworld Aircare Limited | Extraterritorial | 2000 |
| Only Unicorns Ltd | Real estate | 2024 |
| Oosterink Property Ltd | Real estate | 2021 |
| Oosterink Trading Ltd | Hospitality | 2022 |
| Opcom Systems & Consulting Limited | Professional & scientific | 2017 |
| Openzip Ltd | Wholesale & retail | 2021 |
| Operation Q-Labs Limited | Extraterritorial | 2020 |
| Opus Marketing Ltd | Professional & scientific | 2024 |
| Orange Bird Investments Ltd | Real estate | 2021 |
| Orange Court Development Ltd | Construction | 2024 |
| Orangeme Ltd | Other services | 2023 |
| Orchid Court (Egham) Residents Association Limited | Administrative & support | 1995 |
| Origin Trading Ltd | Real estate | 2020 |
| Orno Design Ltd | Wholesale & retail | 2018 |
| ORU Design Limited | Real estate | 2011 |
| OSA Holding Ltd | Professional & scientific | 2022 |
| Osool Ltd | Real estate | 2017 |
| Oswald Stiftung Ltd | Professional & scientific | 2022 |
| Otek Property Developments Limited | Construction | 2024 |
| Otek Property Investments Limited | Real estate | 2018 |
| Otto Bock Healthcare PLC | Manufacturing | 1976 |
| Ottoban Ltd | Health & social care | 2015 |
| OUR Developments Limited | Real estate | 2023 |
| Outdoor Active Camps Ltd | Education | 2024 |
| Outside the Hive Limited | Administrative & support | 2024 |
| Outsourcedx Limited | Professional & scientific | 2022 |
| Oven Doctor Ltd | Administrative & support | 2020 |
| Overboard Limited | Wholesale & retail | 2006 |
| Overflow Capital Ltd | Financial services | 2024 |
| Overflow Investments Ltd | Real estate | 2024 |
| OVIUM4 Real Estate Ltd | Real estate | 2021 |
| Oxtower Invest Ltd | Real estate | 2023 |
| Ozcinar Ltd | Information & communication | 2023 |
| Ozora Ltd | Real estate | 2024 |
| P & H Components 2011 Ltd | Professional & scientific | 2011 |
| P S Bhangu Limited | Health & social care | 2018 |
| P S Trading Limited | Financial services | 2006 |
| P&N Properties Limited | Real estate | 2019 |
| P&N Serviced Properties Ltd | Real estate | 2025 |
| P&R Hosts Ltd | Hospitality | 2023 |
| P&R Property Invest Ltd | Real estate | 2021 |
| P-Consult Ltd | Financial services | 2019 |
| P.Karoz Ltd | Transport & logistics | 2022 |
| Pacific Ecohousing Ltd | Real estate | 2026 |
| Padid Limited | Professional & scientific | 2017 |
| PAF & UK Global .on Ltd | Professional & scientific | 2023 |
| PAF & YK Global .on Ltd | Other services | 2023 |
| Palladian (Kenley) Limited | Construction | 2015 |
| Pama Metals Ltd | Wholesale & retail | 2022 |
| Pampas Rose Ltd | Real estate | 2024 |
| Pandaheart Ltd | Other services | 2023 |
| Paneer Craft Ltd. Limited | Manufacturing | 2025 |