| Oakfield P.M. Limited | Real estate | 1997 |
| Oakfield Property Assets LLP | | 2024 |
| Oakheads Property Limited | Real estate | 2005 |
| Oakmont Building Group Ltd | Construction | 2026 |
| Oakwood Carpentry and Construction Ltd | Manufacturing | 2020 |
| Oast Property Management Ltd | Real estate | 1999 |
| Objectspace Digital Ltd. | Information & communication | 2016 |
| Odyssey Media Limited | Information & communication | 2023 |
| Odyssey SCP Ltd | Arts & recreation | 2023 |
| Offside Pictures Ltd | Information & communication | 2012 |
| OG Services Ltd | Wholesale & retail | 2025 |
| OG Transport and Recovery Ltd | Transport & logistics | 2026 |
| Oiraoira Ltd | Professional & scientific | 2023 |
| Old Roar Company Limited | Real estate | 2004 |
| Old Roar Property Limited | Real estate | 2022 |
| Oldar Ltd | Manufacturing | 2017 |
| Omega 23 Consultancy Limited | Wholesale & retail | 2015 |
| One Life Live IT Ltd | Real estate | 2023 |
| One Mews Road Freehold Limited | Households | 2023 |
| Only Lifts Limited | Manufacturing | 2016 |
| Only Living Limited | Construction | 2025 |
| Onpoint Care Recruitment Limited | Administrative & support | 2017 |
| Onpoint Homecare Ltd | Health & social care | 2019 |
| OOB Business Consulting UK Ltd | Professional & scientific | 2023 |
| Ooty Freehold Management Limited | Extraterritorial | 2007 |
| Opahstore Limited | Wholesale & retail | 2019 |
| Oppynuga Ltd | Health & social care | 2018 |
| Optiflux Ltd | Information & communication | 2026 |
| Optimal Associates Limited | Administrative & support | 2011 |
| Optimum Hvac Ltd | Construction | 2024 |
| Optimum Renewables Ltd | Administrative & support | 2022 |
| Orla Beswick Properties Ltd | Real estate | 2015 |
| Ormazd Services Ltd | Real estate | 2026 |
| Orme Kirby Projects Limited | Professional & scientific | 1998 |
| Otherwise Publishing Limited | Information & communication | 2018 |
| OUR Firm Ltd | Professional & scientific | 2025 |
| OUR Town HAS Plenty Limited | Information & communication | 2025 |
| OUT Nights Ltd | Arts & recreation | 2019 |
| OW Artist Ltd | Wholesale & retail | 2018 |
| Owatbaits Ltd | Agriculture & fishing | 2023 |
| Oyster BOY Events Ltd | Hospitality | 2019 |
| Oyster BOY Markets Ltd | Wholesale & retail | 2024 |
| P & S Electrical (South East) Limited | Construction | 2011 |
| P and L Rentals Limited | Real estate | 2024 |
| Pacemaker of London Ltd. | Arts & recreation | 1995 |
| Pact Pro Ltd | Wholesale & retail | 2026 |
| Paintology Decorators Limited | Construction | 2022 |
| Palace Lettings Ltd | Real estate | 2023 |
| Palmeira Avenue Mansions (East) Ltd | Professional & scientific | 1999 |
| Pamoyo Therapy Ltd | Health & social care | 2026 |
| Panda House 126 Ltd | Hospitality | 2024 |
| Paragon Building & Roofing Limited | Construction | 2020 |
| Parcs Management Services UK Ltd | Hospitality | 2023 |
| Park Lane (New Build) Limited | Construction | 2020 |
| Park Lane Homes (East Sussex) Limited | Real estate | 2015 |
| Park Lane Homes (Eastbourne) Limited | Extraterritorial | 2020 |
| Park Lane Investment Homes Ltd | Real estate | 2020 |
| Park Trading Company Limited | Construction | 1984 |
| Parselle Properties Ltd | Real estate | 2025 |
| Pascf Ltd | Water & waste | 2026 |
| Path IT Summit Ltd | Information & communication | 2025 |
| Pathways Southern Ltd | Information & communication | 2025 |
| Patrick Oliver Ltd | Real estate | 2016 |
| Patron + Saint Limited | Other services | 2024 |
| Payments and Crypto Network Ltd | Information & communication | 2025 |
| Payne Trading Ltd | Wholesale & retail | 2024 |
| Peaceful Deen CIC | Wholesale & retail | 2026 |
| Peaceful Hxxligan Management Ltd | Professional & scientific | 2024 |
| Peden Property Ltd | Real estate | 2016 |
| Peking Diner Sussex Ltd | Hospitality | 2018 |
| Pelican Rental Properties Ltd | Real estate | 2025 |
| Pembridge Enterprises Ltd | Professional & scientific | 2026 |
| Penjwen Car Wash Limited | Wholesale & retail | 2026 |
| Peony Rose Design Ltd | Professional & scientific | 2015 |
| Perception Software and Services Ltd | Information & communication | 2020 |
| Permanex Power Limited | Construction | 2008 |
| Peter Leask Oilfield Consultancy Ltd | Professional & scientific | 2018 |
| Peterkin RPP Limited | Financial services | 2003 |
| Pevensey Court (Freehold) Limited | Households | 2007 |
| Pevensey Road Management Company Ltd | Households | 2007 |
| PH Design Services Limited | Construction | 2006 |
| Phoenix & Plum Limited | Professional & scientific | 2012 |
| Phoenix Garden Takeaway Ltd | Hospitality | 2024 |
| Photek Limited | Manufacturing | 1991 |
| Piece of Cake (UK) Ltd | Wholesale & retail | 2006 |
| Pilgrimage & Energy Enterprises Ltd | Health & social care | 2025 |
| PIN Care Limited | Administrative & support | 2016 |
| Pixel Media for YOU Ltd | Administrative & support | 2016 |
| Pizzarelli Ltd | Hospitality | 2019 |
| Plaster DEC Limited | Construction | 2025 |
| Plastering for Beginners Ltd | Education | 2020 |
| Platformer Media Ltd | Professional & scientific | 2021 |
| PLP House Maintenance Ltd | Construction | 2017 |
| PM Rizzardi Ltd | Construction | 2016 |
| PN Storage Ltd | Real estate | 2026 |
| Positive Impact (Sales) Ltd | Wholesale & retail | 2008 |
| Powertrade Ltd | Construction | 2018 |
| PPC Property Development Limited | Construction | 2015 |
| Pralea Services Ltd | Administrative & support | 2018 |
| Precious Cleans Ltd | Administrative & support | 2024 |