| Oculus Wealth Management (FPG) Limited | Financial services | 2024 |
| Oculus Wealth Management (Godalming) Limited | Financial services | 2022 |
| Oculus Wealth Management (Greater London) Limited | Financial services | 2023 |
| Oculus Wealth Management (Hampshire) Limited | Financial services | 2021 |
| Oculus Wealth Management (Home Counties) Limited | Financial services | 2024 |
| Oculus Wealth Management (Integritas) Limited | Financial services | 2026 |
| Oculus Wealth Management (Kensington and Chelsea) Limited | Financial services | 2025 |
| Oculus Wealth Management (Leeds) Limited | Financial services | 2021 |
| Oculus Wealth Management (Leicestershire) Limited | Financial services | 2019 |
| Oculus Wealth Management (Leodis) Limited | Financial services | 2024 |
| Oculus Wealth Management (Lichfield) Limited | Financial services | 2024 |
| Oculus Wealth Management (London) Limited | Extraterritorial | 2019 |
| Oculus Wealth Management (Marlborough) Limited | Financial services | 2023 |
| Oculus Wealth Management (Mayfair) Limited | Financial services | 2021 |
| Oculus Wealth Management (Minerva) Limited | Financial services | 2025 |
| Oculus Wealth Management (New Forest) Limited | Financial services | 2026 |
| Oculus Wealth Management (Nexus) Limited | Financial services | 2025 |
| Oculus Wealth Management (Phronesis) Limited | Financial services | 2025 |
| Oculus Wealth Management (Reigate) Limited | Financial services | 2025 |
| Oculus Wealth Management (Shropshire) Limited | Financial services | 2021 |
| Oculus Wealth Management (Solihull) Limited | Financial services | 2025 |
| Oculus Wealth Management (South London) Limited | Financial services | 2023 |
| Oculus Wealth Management (South Staffs) Limited | Financial services | 2020 |
| Oculus Wealth Management (Truro) Limited | Financial services | 2024 |
| Oculus Wealth Management (Warwickshire) Limited | Financial services | 2025 |
| Oculus Wealth Management (Wessex) Limited | Financial services | 2020 |
| Oculus Wealth Management (West London) Limited | Financial services | 2025 |
| Oculus Wealth Management (West Midlands) Limited | Professional & scientific | 2020 |
| Oculus Wealth Management (Westminster) Limited | Financial services | 2023 |
| Oculus Wealth Management (Wolverhampton) Limited | Financial services | 2020 |
| Oculus Wealth Management (Wombourne) Limited | Financial services | 2020 |
| Oculus Wealth Management (York) Limited | Financial services | 2023 |
| OD 333 Limited | Extraterritorial | 2025 |
| OD 3333 Limited | Extraterritorial | 2025 |
| ODA1 Ltd | Health & social care | 2015 |
| Oddy Productions Ltd | Information & communication | 2026 |
| Odessa Associates Ltd | Other services | 2012 |
| Odyssey Hair Salon Ltd | Other services | 2022 |
| Odyssey Sailing Ltd | Administrative & support | 2021 |
| Oeco Garden Rooms Ltd | Construction | 2023 |
| OF Pharm Ltd | Administrative & support | 2022 |
| Offgridly Ltd | Information & communication | 2024 |
| Official Sports Services Ltd | Health & social care | 2019 |
| Ogden Group Holdings Limited | Financial services | 2019 |
| Ogden Natural Health Ltd | Professional & scientific | 2022 |
| Ogilvy Newall Limited | Extraterritorial | 2026 |
| Oglesby Limited | Extraterritorial | 2026 |
| OH Coco Ltd | Other services | 2022 |
| Ohana Food Company Ltd | Hospitality | 2023 |
| Ohes Environmental Limited | Professional & scientific | 2001 |
| OIL FM Limited | Extraterritorial | 2015 |
| OK FM Ltd | Extraterritorial | 2015 |
| Okiplay Ltd | Information & communication | 2012 |
| OL1VIA Limited | Extraterritorial | 2020 |
| Old Acquilla Investment Company | Administrative & support | 2015 |
| Old Glory Limited | Wholesale & retail | 2020 |
| Old Hardisty Ltd | Extraterritorial | 2026 |
| Old Swan Court Management Company Limited | Households | 2000 |
| Oldgate Textiles Limited | Manufacturing | 1997 |
| Oldridge Windows Limited | Manufacturing | 2005 |
| Olexor Limited | Professional & scientific | 2017 |
| OLIV1A Limited | Extraterritorial | 2020 |
| Olive Garden Design & Landscaping Limited | Administrative & support | 2005 |
| Olive PM Ltd | Professional & scientific | 2023 |
| Oliver Carter Heating Ltd | Construction | 2015 |
| Olivers Fish Restaurant Limited | Hospitality | 2004 |
| Oliveta Limited | Hospitality | 2021 |
| Olleys Ristorante Ltd | Hospitality | 2022 |
| Olsen Group Limited | Extraterritorial | 2026 |
| Omar Property Holdings | Financial services | 2024 |
| Omen Tattoo Ltd | Arts & recreation | 2025 |
| Omicron Claims Limited | Wholesale & retail | 2021 |
| Omid Mangal Logistics Ltd | Wholesale & retail | 2023 |
| Omni Media & Tech Ltd | Information & communication | 2025 |
| Omni Sourcing Limited | Wholesale & retail | 2023 |
| Omura Ltd | Information & communication | 2023 |
| ON the Spot Development Limited | Information & communication | 2016 |
| Ondaworx Ltd | Information & communication | 2026 |
| One Brewery Wharf Limited | Real estate | 2004 |
| One Brush Limited | Wholesale & retail | 2025 |
| One Co. of Harrogate Ltd | Manufacturing | 2016 |
| One Gym Collingham Limited | Arts & recreation | 2020 |
| One Hair Styling Ltd | Wholesale & retail | 2024 |
| One Homes York Ltd | Real estate | 2016 |
| One Nine Signs Limited | Professional & scientific | 2019 |
| One North Enterprise Limited | Information & communication | 2016 |
| One Service Group Limited | Administrative & support | 2019 |
| One Shot Limited | Information & communication | 2009 |
| One Venture Place Ltd. | Professional & scientific | 2015 |
| One Virtual Limited | Administrative & support | 2020 |
| Onebrightday Limited | Administrative & support | 2008 |
| Oneline Surveys Ltd. | Other services | 2007 |
| Onesys Limited | Information & communication | 1992 |
| Onesys Support Ltd | Financial services | 1992 |
| Onion Consulting Limited | Professional & scientific | 2023 |
| Online Bottlers Limited | Manufacturing | 1997 |
| Online Security Products Ltd | Wholesale & retail | 2007 |
| Onsite Kitchen Respray Specialists Ltd | Construction | 2024 |
| Onward Bound Limited | Information & communication | 2023 |
| Oort Limited | Hospitality | 2006 |