| New Hope Wirral CIC | Other services | 2026 |
| New Learning Hub Limited | Education | 2021 |
| New Tower Construction UK Ltd | Construction | 2025 |
| New Tower Developments UK Limited | Construction | 2023 |
| Newton Flat Management Limited | Households | 1999 |
| Nexgen Plumbing and Heating Ltd | Construction | 2026 |
| Next Chapter (NW) CIC | Education | 2014 |
| NG Clinic Ltd | Other services | 2023 |
| NH Investment Consulting Limited | Professional & scientific | 2026 |
| Nickel City UK Ltd | Hospitality | 2022 |
| Nicola Gardens Management Company Limited | Administrative & support | 2013 |
| Nimrod Contracting Limited | Construction | 2017 |
| Nineteen 86 Marketing Limited | Professional & scientific | 2019 |
| Nirthi Ltd | Wholesale & retail | 2021 |
| NJS Coaching and Consulting Ltd | Professional & scientific | 2019 |
| NJS Properties London Limited | Real estate | 2021 |
| Nlis.Ltd | Professional & scientific | 2003 |
| NLL Nails Ltd | Other services | 2022 |
| NLP Music & Entertainment Ltd | Arts & recreation | 2023 |
| NLR Trading Limited | Wholesale & retail | 2017 |
| Noah London GTM Consultancy Limited | Administrative & support | 2026 |
| Noochoon Ltd | Wholesale & retail | 2023 |
| North Drive Apartments Limited | Households | 2018 |
| North Drive Limited | Real estate | 2014 |
| North Star Reflex Integration CIC | Education | 2026 |
| North Sunset Limited | Real estate | 2025 |
| Northcliffe Rennovations Limited | Real estate | 2015 |
| Northern Barbers Wallasey Limited | Other services | 2016 |
| Northern Progression Ltd | Education | 2026 |
| Northern Theatrics Ltd | Arts & recreation | 2025 |
| Northsure Law Limited | Professional & scientific | 2017 |
| Northwest Ceilings & Partitions Ltd | Construction | 2023 |
| Nsdb Pipeworks Ltd | Manufacturing | 2022 |
| Nuepos Ltd | Information & communication | 2018 |
| Numast Pension Trustees (Section 226) Limited | Financial services | 1986 |
| Number Run Limited | Administrative & support | 2024 |
| NW Locks Contracts Ltd | Construction | 2025 |
| NW Regional Inns Limited | Hospitality | 2020 |
| Oakdale Opportunities Limited | Education | 2003 |
| Oakhill Assets Limited | Real estate | 2023 |
| Oakley Wholesale Ltd | Wholesale & retail | 2021 |
| Oakrise Property Limited | Real estate | 2021 |
| Oakwood Engraving Limited | Wholesale & retail | 2025 |
| Oblivioncreatornetwork Ltd | Information & communication | 2026 |
| Ocean Branding Limited | Administrative & support | 1997 |
| Ocean Wave Chippy Ltd | Hospitality | 2024 |
| Oceanair Services Limited | Construction | 1981 |
| Oceans Trade Ltd | Wholesale & retail | 2024 |
| Octansweb Ltd | Information & communication | 2023 |
| Odlum Capital Ltd | Financial services | 2025 |
| OFF - CUT Barbers LLP | | 2018 |
| OFF CUT Barbers Camberwell Limited | Other services | 2020 |
| OFF CUT Barbers Crystal Palace Limited | Other services | 2020 |
| OFF CUT Barbers Peckham Limited | Other services | 2023 |
| OFF CUT Barbers Streatham Limited | Other services | 2021 |
| OFF CUT Holdings Limited | Other services | 2020 |
| OFF the Rock Bike Park CIC | Education | 2023 |
| OFF the Rock Cycles Ltd. | Wholesale & retail | 2017 |
| Off-Cut Barkers Peckham Limited | Wholesale & retail | 2025 |
| Olawa Community Lounge CIC | Health & social care | 2024 |
| Olawa Ltd | Hospitality | 2026 |
| Old Time Strength UK Ltd | Manufacturing | 2020 |
| Olimarie Ltd | Manufacturing | 2023 |
| Olistico Ltd | Wholesale & retail | 2022 |
| Olivia James Hairdressing Ltd | Other services | 2023 |
| OLM Utilities Limited | Professional & scientific | 2024 |
| Once a Blue, Always a Blue Ltd | Wholesale & retail | 2025 |
| One for the Ditch Ltd | Hospitality | 2022 |
| One Step Games Ltd | Wholesale & retail | 2022 |
| Oneill Family Properties Ltd | Real estate | 2024 |
| Opendigital.Media Limited | Professional & scientific | 2025 |
| Ophthalmic Market Access Ltd | Wholesale & retail | 2015 |
| OPM Renewables Limited | Professional & scientific | 2025 |
| OPS Engineering Limited | Professional & scientific | 2016 |
| Optima Brands Limited | Wholesale & retail | 2024 |
| OQL Live Ltd | Arts & recreation | 2024 |
| Oriental Chef 888 Ltd | Hospitality | 2026 |
| Origin Probate Research Ltd | Information & communication | 2019 |
| OS Buy & LET Ltd | Real estate | 2022 |
| OS Buy to LET Ltd | Real estate | 2023 |
| Osiris Dining Ltd | Hospitality | 2024 |
| OT Ideas Limited | Health & social care | 2009 |
| OTA Global Traders Ltd | Wholesale & retail | 2025 |
| Ours Social Ltd | Hospitality | 2026 |
| OUT of the Attic Ltd | Wholesale & retail | 2021 |
| Outdoor Returns Limited | Wholesale & retail | 2017 |
| Outlandic Ltd | Wholesale & retail | 2024 |
| Overchurch Public House Ltd | Hospitality | 2025 |
| Oxon Design Ltd | Professional & scientific | 2021 |
| P P Electrical Services Limited | Construction | 2015 |
| P&L External Cleaning Ltd | Administrative & support | 2026 |
| P.M.C. Trading Limited | Wholesale & retail | 2021 |
| PAB EP Limited | Hospitality | 2024 |
| PAB Leisure (NW) Ltd | Hospitality | 2024 |
| Paghman Housing Ltd | Households | 2021 |
| Palatine Development Ltd | Construction | 2026 |
| Pali Warrington Ltd | Real estate | 2006 |
| Pana Developments Limited | Construction | 2023 |
| Panda-Moniumworld Ltd | Manufacturing | 2026 |
| Panoramic Windows Ltd | Manufacturing | 2023 |