| Offshore Connections Ltd | Administrative & support | 2025 |
| OI OI the Shop Ltd | Wholesale & retail | 2018 |
| Olbos Ltd | Real estate | 2025 |
| Old School JAM Ltd | Hospitality | 2026 |
| Olimpik London Table and Chair Ltd | Wholesale & retail | 2022 |
| Olive Branch Recruitment Ltd | Administrative & support | 2023 |
| Oliver & Juggins Property Group Limited | Real estate | 2019 |
| Oliver Property Holdings Ltd | Real estate | 2022 |
| Ollymo Ltd | Information & communication | 2026 |
| Olympus School of Swimming Limited | Education | 2023 |
| ON Investment Partners Limited | Wholesale & retail | 2024 |
| ON Smash Ltd | Hospitality | 2026 |
| ON Top Roofing Specialists Ltd | Construction | 2025 |
| One Baltic Wharf LLP | | 2025 |
| One Cafe Bedford Limited | Hospitality | 2016 |
| One Call Security Limited | Administrative & support | 2026 |
| One Hampton Limited | Real estate | 2022 |
| One Love Shop & Munchies Cafe Ltd | Wholesale & retail | 2017 |
| One Payroll Services Ltd | Administrative & support | 2012 |
| One Payroll Solutions Limited | Administrative & support | 2014 |
| ONE2ONE UK Fashion Ltd | Other services | 2025 |
| ONE4ALL Property Services Ltd | Construction | 2024 |
| Only Chicken Ltd | Hospitality | 2024 |
| Onslow Road Ltd | Real estate | 2025 |
| Opek Services Limited | Hospitality | 2014 |
| Open Creative Consultants Ltd | Administrative & support | 1999 |
| Open Door Services Ltd | Professional & scientific | 2025 |
| OPS Stellar Innovations Ltd | Construction | 2023 |
| Option 42 Limited | Information & communication | 2019 |
| Orbital Civil Engineering Limited | Construction | 2017 |
| Orchard Park (Cambridge) Management Company Limited | Households | 2022 |
| Organic Mania Limited | Wholesale & retail | 2021 |
| Organisedbread Ltd | Financial services | 2024 |
| Organopeel Ltd | Wholesale & retail | 2022 |
| Orikan Media Ltd | Professional & scientific | 2023 |
| Orion Nebula Limited | Wholesale & retail | 2018 |
| Ortega Ltd | Wholesale & retail | 2013 |
| Ossa 01 Ltd | Hospitality | 2022 |
| Osteria Wolf Ltd | Hospitality | 2019 |
| Otis Property Management Ltd | Real estate | 2020 |
| Otty Investments Ltd | Administrative & support | 2024 |
| Ouch Tattoo Limited | Other services | 2016 |
| OUR Best Builder Ltd | Construction | 2025 |
| Outsource Professional Directors (OPD) Limited | Professional & scientific | 2020 |
| Oval Locum Services Limited | Health & social care | 2018 |
| Overleaf Landscapes Ltd | Administrative & support | 2016 |
| Overmay Limited | Hospitality | 2015 |
| Ovidiu Selaru Photographer Ltd | Professional & scientific | 2024 |
| Ovule Consulting Limited | Professional & scientific | 2024 |
| Ower Healthcare Ltd | Health & social care | 2024 |
| Owiredufiftys Co Ltd | Health & social care | 2014 |
| Ownsunny Property Management Limited | Households | 1999 |
| Ozcelik 1 Property Investment Limited | Real estate | 2026 |
| Ozerbag Limited | Real estate | 2026 |
| Ozlem Akay Ltd | Wholesale & retail | 2009 |
| Ozzyfood Ltd | Wholesale & retail | 2021 |
| P & P Aquatics Ltd | Agriculture & fishing | 2021 |
| P & S Taxi Service Limited | Transport & logistics | 2019 |
| P.R.S. (Pallets) Limited | Other services | 1994 |
| Pacific Distribution Ltd | Wholesale & retail | 2025 |
| Pacific Grills UK Limited | Hospitality | 2023 |
| Padlock App Limited | Manufacturing | 2023 |
| Padmapriya CS Limited | Manufacturing | 2015 |
| PAH CME Solutions Limited | Professional & scientific | 2017 |
| Palace Coffee and Dessert Ltd | Hospitality | 2026 |
| Palace Internet Limited | Information & communication | 2022 |
| Palao Donau Limited | Hospitality | 2019 |
| Palmer Collective Ltd | Professional & scientific | 2026 |
| PAN Ceramics Limited | Construction | 2006 |
| Panda Align Ltd | Manufacturing | 2025 |
| Pangea Sports Consultancy Ltd | Financial services | 2023 |
| Panther Organix Limited | Wholesale & retail | 2020 |
| Papis Investments Limited | Real estate | 2025 |
| Parama E Ltd | Wholesale & retail | 2023 |
| Parker Trees Ltd | Administrative & support | 2025 |
| Parla Investment Ltd | Construction | 2026 |
| Parma Cafe Ltd | Hospitality | 2024 |
| Partners in Retail Limited | Wholesale & retail | 2025 |
| Partners Three Ltd | Professional & scientific | 2026 |
| Passion Hairstyling Limited | Other services | 2020 |
| Patrick Morrison Limited | Professional & scientific | 2013 |
| Patriot Consultancy Ltd | Professional & scientific | 2025 |
| Paul Atkinson Design Ltd | Arts & recreation | 2010 |
| Paul Blackmore Limited | Extraterritorial | 2009 |
| Paulanto Holdings Ltd | Financial services | 2023 |
| Pav-Bg Ltd | Construction | 2020 |
| Pavilion Fish Limited | Hospitality | 2016 |
| Paws & Perch Ltd | Wholesale & retail | 2026 |
| Pawsome Products Ltd | Wholesale & retail | 2023 |
| Payments 4 YOU Ltd | Professional & scientific | 2026 |
| Pbod Limited | Other services | 2025 |
| PDB90 Ltd | Transport & logistics | 2022 |
| Pdev Ltd | Construction | 2021 |
| PDL Associates Limited | Professional & scientific | 2018 |
| PDR Smart Management Limited | Wholesale & retail | 2026 |
| Pds-Uk Limited | Water & waste | 2019 |
| Peachwood Design Studio Ltd | Professional & scientific | 2023 |
| Pearls Café (Snacks) Limited | Manufacturing | 2016 |
| Pennywise Warehouse Limited | Wholesale & retail | 2026 |
| Penparc Holdings Limited | Financial services | 2022 |