| O & P Wholesale Limited | Extraterritorial | 2007 |
| Oakwood Autohaus Ltd | Wholesale & retail | 2026 |
| OBA Beauty Brand Ltd | Wholesale & retail | 2024 |
| OBAMA1 Restaurant Limited | Hospitality | 2022 |
| OBAMA1 Unisex Salon Ltd | Other services | 2021 |
| Obsidian Property Holdings Ltd | Real estate | 2026 |
| Ocabique Njalah Food Limited | Wholesale & retail | 2026 |
| Ocean Speed Tyres Ltd | Wholesale & retail | 2026 |
| Oceana Pizza and Kebab Limited | Hospitality | 2026 |
| OEM Alloy Wheels Ltd | Wholesale & retail | 2020 |
| OHD Property Limited | Real estate | 2020 |
| Oitis Ltd | Real estate | 2025 |
| Old Talbot Limited | Hospitality | 2016 |
| Oldbury Hardware Ltd | Wholesale & retail | 2021 |
| Olive Tree C S Ltd | Hospitality | 2026 |
| Olympus Digital Solutions Limited | Information & communication | 2026 |
| Ombn Ltd | Real estate | 2021 |
| Omega Inc Limited | Transport & logistics | 2026 |
| Omni Habitat Ltd | Manufacturing | 2026 |
| Omnisa Limited | Information & communication | 2021 |
| Omono Clothing Shop Limited | Wholesale & retail | 2023 |
| Omono Sports Consultancy Limited | Arts & recreation | 2026 |
| Omono Textiles Ltd | Wholesale & retail | 2016 |
| ON Route Express Ltd | Transport & logistics | 2024 |
| On-Top Courier U.K. Ltd | Transport & logistics | 2023 |
| Onatio Ltd | Wholesale & retail | 2021 |
| Oncoyoga Ltd | Health & social care | 2026 |
| One Way Cycles Ltd | Wholesale & retail | 2022 |
| Onego Travel Limited | Administrative & support | 2018 |
| Onepeople Care Solutions Ltd | Health & social care | 2025 |
| ONK Wholesale Limited | Wholesale & retail | 2025 |
| Onki Properties Ltd | Real estate | 2022 |
| Online Transport Limited | Transport & logistics | 2021 |
| Only Vapes and Juices Ltd | Wholesale & retail | 2025 |
| Onpoint Facilities Management Ltd | Information & communication | 2022 |
| Onpoint Global Services Ltd | Information & communication | 2020 |
| Onye Restaurant Ltd | Hospitality | 2023 |
| Opal Banqueting Ltd | Real estate | 2019 |
| Optimal Westmidlands Ltd | Wholesale & retail | 2018 |
| Optimus Solutions Ltd | Construction | 2025 |
| Optiverse Technologies Ltd | Information & communication | 2023 |
| Orchard Properties Development Limited | Real estate | 2025 |
| Orderinn Ltd | Information & communication | 2013 |
| Organzy Group Limited | Wholesale & retail | 2019 |
| Orosunola Limited | Manufacturing | 2025 |
| Orwin and Bruce Associates Limited | Arts & recreation | 1983 |
| Osprey Engineering Solutions Limited | Administrative & support | 2016 |
| Osprey Sales Recruitment Limited | Administrative & support | 2025 |
| OST Consulting and Care Limited | Administrative & support | 2019 |
| OT Builder Ltd | Construction | 2019 |
| OUR Choice Holidays Ltd | Administrative & support | 2023 |
| OUR Choice Products Ltd | Wholesale & retail | 2023 |
| OUT of Hours XYZ Ltd | Information & communication | 2024 |
| Overhaul Roofing Ltd | Construction | 2020 |
| Overhear Ltd | Arts & recreation | 2019 |
| Overhear Well-Being CIC | Health & social care | 2019 |
| Own Builders Ltd | Construction | 2022 |
| Ownerts Limited | Wholesale & retail | 2026 |
| OWO360 Ltd | Information & communication | 2025 |
| Oxford 12 Ltd | Hospitality | 2026 |
| Oxford PJ Admin Ltd | Administrative & support | 2024 |
| Oxyleon Group Limited | Information & communication | 2018 |
| Ozumbazaar Limited | Manufacturing | 2023 |
| P a Dhaliwal Property Limited | Real estate | 2022 |
| P Bhangu Property Services Ltd | Real estate | 2025 |
| P G Crawford Limited | Other services | 2013 |
| P Townsend Limited | Information & communication | 2014 |
| P.T.A Estate Ltd | Real estate | 2021 |
| PAB Cleaning Limited | Administrative & support | 2025 |
| Pack and Go Logistics Ltd | Transport & logistics | 2020 |
| Paeblue Courier Ltd | Transport & logistics | 2025 |
| Pagan Hairdressing Ltd | Administrative & support | 2007 |
| Paint Plant Services Limited | Manufacturing | 2012 |
| Painting and Cleaning Ltd | Construction | 2025 |
| PAK Security Guards Limited | Administrative & support | 2023 |
| PAK Supermarket (Oldbury) Ltd | Wholesale & retail | 2021 |
| Pall Property Projects Limited | Wholesale & retail | 2010 |
| Pallas Shawarma Ltd | Other services | 2024 |
| Palopis Star Limited | Wholesale & retail | 2023 |
| PAN Couriers Ltd | Transport & logistics | 2024 |
| Panwar Ltd | Wholesale & retail | 2020 |
| PAP Properties 2025 Ltd | Real estate | 2025 |
| Paparazzi Holdings Limited | Financial services | 2023 |
| Paradise Wholesale Limited | Manufacturing | 2025 |
| Paraman Cyber Consultant Ltd | Information & communication | 2024 |
| Paramount (South London) Limited | Manufacturing | 2025 |
| Paramount Build & Development Ltd | Construction | 2026 |
| Paras Paper Mart Ltd | Wholesale & retail | 2025 |
| Parcel Track Ltd | Transport & logistics | 2025 |
| Paris Express WM Ltd | Construction | 2020 |
| Parkash Properties Ltd | Construction | 2025 |
| Parsy DM Consultancy Ltd | Information & communication | 2024 |
| Party Decorator Online Ltd | Wholesale & retail | 2022 |
| Party Glamour Limited | Other services | 2015 |
| Party Masters Ltd | Wholesale & retail | 2024 |
| Parveen Ahmed Pharma Ltd | Health & social care | 2014 |
| PAS Transport MG Ltd | Transport & logistics | 2025 |
| Pass Factor Limited | Transport & logistics | 2008 |
| Pass With Flying Colours (Birmingham) Ltd | Education | 2014 |
| Passenger Lift Group Limited | Professional & scientific | 2023 |