| Ollyboo Limited | Financial services | 2018 |
| OLLYBOO2 Limited | Real estate | 2021 |
| Olmtsc Ltd | Wholesale & retail | 2021 |
| OLR School Holdings Limited | Financial services | 2025 |
| OLR School Property Limited | Real estate | 2025 |
| OLS Properties Limited | Real estate | 2014 |
| OLS Tyres Ltd | Wholesale & retail | 2020 |
| Olsen & Olsen Hairdressing Limited | Other services | 2014 |
| Olsen Consultancy Ltd | Information & communication | 2023 |
| Olsen Haulage Ltd | Transport & logistics | 2026 |
| Olsens Limited | Transport & logistics | 2023 |
| Oludam Limited | Real estate | 2017 |
| Oluwabusola Ltd | Health & social care | 2026 |
| Olympia Properties (Liverpool) Ltd | Extraterritorial | 2019 |
| Olympic Bowling Club Company,Limited | Arts & recreation | 1892 |
| Olympic Scaffold & Tower Hire Limited | Construction | 1992 |
| Olympus Campervan Hire Ltd | Administrative & support | 2025 |
| Olympus Nutrition Ltd | Wholesale & retail | 2025 |
| Olympus Padel Limited | Arts & recreation | 2026 |
| OM Property Lettings Ltd | Real estate | 2023 |
| OM Sairam Food Limited | Hospitality | 2022 |
| OM Sairam Housing Ltd | Real estate | 2025 |
| Omani Kitchen Ltd | Hospitality | 2024 |
| Omar's Health Care Limited | Health & social care | 2024 |
| Ombush Media Limited | Information & communication | 2017 |
| Omdur L7 Ltd | Hospitality | 2026 |
| Omdurman Restaurant Ltd | Hospitality | 2023 |
| OME Solutions Ltd | Professional & scientific | 2026 |
| Omega Global Media Ltd | Information & communication | 2023 |
| Omega LEC FM Ltd | Construction | 2020 |
| Omega LED Limited | Manufacturing | 2009 |
| Omega Maintenance Limited | Households | 2024 |
| Omega Project Management Ltd | Construction | 2019 |
| Omega Recruitment Services Limited | Administrative & support | 2016 |
| Omega Techniks UK Ltd | Manufacturing | 2024 |
| Omega Therapy, Health and Fitness Limited | Education | 2017 |
| Omega Tile Supplies Ltd | Manufacturing | 2025 |
| Omegah Ltd | Real estate | 2021 |
| OMG L1 Venue Limited | Financial services | 2021 |
| OMG Road Transport Ltd | Transport & logistics | 2023 |
| OMI Alloy Wheels Limited | Wholesale & retail | 2021 |
| Omia Interiors Ltd | Professional & scientific | 2021 |
| Omicron 3 Limited | Hospitality | 2022 |
| Ominous Holdings Ltd | Information & communication | 2024 |
| Omneco Group Limited | Financial services | 2026 |
| Omni Communications Limited | Information & communication | 2022 |
| Omnia Building Consultancy Ltd | Professional & scientific | 2020 |
| Omnia Construction (North West) Limited | Construction | 2022 |
| Omnia Group Ltd | Professional & scientific | 2017 |
| Omnia Heritage Limited | Construction | 2025 |
| Omnia Made Ltd | Wholesale & retail | 2023 |
| Omnia MEP Design Ltd | Professional & scientific | 2022 |
| Omnia Nexus Ltd | Wholesale & retail | 2023 |
| Omnia Print Solutions Limited | Manufacturing | 2018 |
| Omnis Property Ltd | Real estate | 2024 |
| Omnity Care Consultancy Ltd | Professional & scientific | 2026 |
| Omodav Global Ltd | Wholesale & retail | 2023 |
| ON Beat DJ School Ltd | Education | 2026 |
| ON Build Design Ltd | Construction | 2017 |
| ON in Five Production Ltd | Arts & recreation | 2020 |
| ON Point Direct Limited | Wholesale & retail | 2018 |
| ON Point Property Services Ltd | Real estate | 2025 |
| ON Point Wine Bar Limited | Hospitality | 2019 |
| ON Screen Traffic Ltd | Professional & scientific | 2026 |
| ON Target Ltd | Wholesale & retail | 2021 |
| ON the Court Limited | Information & communication | 2024 |
| ON the DOT Property Ltd | Real estate | 2025 |
| ON the Go Grab Ltd | Hospitality | 2025 |
| ON the Go Liverpool Ltd | Hospitality | 2025 |
| ON the MIC Limited | Information & communication | 2021 |
| ON Time Services Limited | Professional & scientific | 2021 |
| ON Track Liverpool CIC | Information & communication | 2024 |
| ON Your Doorstep Ltd | Professional & scientific | 2014 |
| On-Site Energy Europe Limited | Energy | 2024 |
| On-Site Energy Limited | Energy | 2021 |
| On-Site Northwest Civil Engineering Ltd | Construction | 2025 |
| Onchain Ltd | Information & communication | 2021 |
| One 1 Point Direct Ltd | Wholesale & retail | 2024 |
| One 100 Consulting Ltd | Professional & scientific | 2020 |
| One and Zero Data Services Ltd | Professional & scientific | 2010 |
| One by Elite Ltd | Real estate | 2026 |
| One Call Cleaning (NW) Ltd | Administrative & support | 2023 |
| One Child at a Time Ltd | Arts & recreation | 2026 |
| One Cool Pumpkin Ltd | Professional & scientific | 2019 |
| One Derby Square Limited | Real estate | 2017 |
| One Direct Solutions Limited | Administrative & support | 2025 |
| One Emergency Liverpool Limited | Health & social care | 2024 |
| One Fell Swoop Limited | Professional & scientific | 2012 |
| One Grip UK Ltd | Wholesale & retail | 2018 |
| One Housing Foundation | Health & social care | 2002 |
| One Housing Investment Limited | Financial services | 2019 |
| One HR Software Ltd | Administrative & support | 2014 |
| One Hundred and ATE Tea Ltd | Hospitality | 2023 |
| One MAN International Limited | Administrative & support | 2024 |
| One MAY Studio Ltd | Professional & scientific | 2022 |
| One Percenters Ltd | Wholesale & retail | 2022 |
| One Planet Communications Limited | Professional & scientific | 2020 |
| One Point Direct Ltd | Wholesale & retail | 2024 |
| One Rose Lane Limited | Other services | 2022 |
| One Stop Candy Limited | Wholesale & retail | 2025 |