| Norton Pizza Co Limited | Hospitality | 2022 |
| Noruk Holding Limited | Real estate | 2026 |
| Noruk Invest Limited | Health & social care | 2020 |
| Noruk Limited | Health & social care | 2010 |
| Norwich Crematorium Holdings Limited | Extraterritorial | 1994 |
| Norwich Crematorium Limited | Extraterritorial | 1935 |
| Nosto Hospitality Ltd | Hospitality | 2023 |
| Nothing to Lou's Limited | Professional & scientific | 2022 |
| Nova Develop Ltd | Real estate | 2016 |
| Nova Insights Ltd | Other services | 2020 |
| Novadom Limited | Real estate | 2023 |
| Novelle Care Ltd | Health & social care | 2024 |
| NP Investments (Stamford) Ltd | Real estate | 2009 |
| NP Legal Consultancy Ltd | Professional & scientific | 2025 |
| NP Leisure Stamford Ltd | Hospitality | 2021 |
| NP Sale Limited | Real estate | 2017 |
| Npdsw Ltd | Real estate | 2024 |
| NQN Analogue Limited | Wholesale & retail | 2022 |
| NR1 Hair Micropigmentation Ltd | Other services | 2024 |
| NRG Industries Limited | Administrative & support | 2007 |
| Nrjh Freight & Haulage Ltd | Transport & logistics | 2024 |
| Nrjh Freight Ltd | Transport & logistics | 2022 |
| NS Slater Ltd | Wholesale & retail | 2022 |
| Nsas Properties Limited | Households | 2024 |
| NSJ Investment Group Limited | Real estate | 2018 |
| Nsjk Property Services Ltd | Real estate | 2020 |
| Nt&M UK Limited | Professional & scientific | 2015 |
| NTN Construction Group Limited | Construction | 2025 |
| NTS Greeting Card Company Ltd | Wholesale & retail | 2023 |
| NTT Cafe Ltd | Hospitality | 2023 |
| Nubeauty (Sutton Coldfield) Ltd | Other services | 2019 |
| Nubian Funeral Directors Limited | Extraterritorial | 1981 |
| Nudgi Ltd | Professional & scientific | 2026 |
| Numan Enterprise Ltd | Health & social care | 2022 |
| Number 6 (Coleshill) Limited | Administrative & support | 2018 |
| Nutcha Sutton Coldfield Ltd | Health & social care | 2023 |
| Nutford Holdings Limited | Financial services | 2022 |
| Nutri-Align Ltd | Wholesale & retail | 2011 |
| Nutriconsultancy Limited | Professional & scientific | 2024 |
| Nuturahealth Ltd | Hospitality | 2024 |
| Nuvue Studios Limited | Professional & scientific | 2020 |
| NW Residentialgroup Ltd | Real estate | 2026 |
| Nxtgen Wills Ltd | Financial services | 2024 |
| Nyxiom Limited | Education | 2025 |
| O S Y Karios Limited | Hospitality | 2021 |
| O'Reilly Financial Solutions Ltd | Professional & scientific | 2009 |
| O3A Limited | Construction | 2010 |
| Oadby Engineering Limited | Manufacturing | 2014 |
| Oak & Prime Ltd | Real estate | 2021 |
| Oak Building & Construction Ltd | Construction | 2021 |
| Oak Gardens Trading Ltd | Wholesale & retail | 2026 |
| Oakbridge Living Limited | Real estate | 2025 |
| Oakbuild Construction Ltd | Construction | 2018 |
| Oakbury Developments Ltd | Administrative & support | 1996 |
| Oakbury Watch Co (Balearics) Ltd | Wholesale & retail | 2025 |
| Oaken Property Finance Ltd | Financial services | 2022 |
| Oakey Properties Ltd | Real estate | 2016 |
| Oakhurst (Sutton Coldfield) Limited | Administrative & support | 2012 |
| Oakland Garage Limited | Wholesale & retail | 2018 |
| Oaklands Croft Management Company Limited | Hospitality | 1983 |
| Oakley Architects Ltd | Professional & scientific | 2012 |
| Oakley Recruitment Ltd | Administrative & support | 2020 |
| Oakline Housing Limited | Real estate | 2026 |
| Oaks Drive Ltd | Households | 2013 |
| Oaks Property Group Limited | Real estate | 2022 |
| Oaks Woodworm Damproofing Co. Limited(The) | Administrative & support | 1976 |
| Oakup Limited | Wholesale & retail | 2024 |
| Oakwood Builders Telford Ltd | Construction | 2026 |
| Oakwood House Livery Limited | Arts & recreation | 2003 |
| Oakwood Management Wood END Ltd | Real estate | 2022 |
| Oasis Lettings (Birmingham) Ltd | Real estate | 2016 |
| OAT Studio Limited | Administrative & support | 2021 |
| Obelisk Mountain Ltd | Construction | 2024 |
| Obhi Holdings Limited | Financial services | 2018 |
| Observoir Limited | Health & social care | 2012 |
| Obsessions Boutique Limited | Wholesale & retail | 2019 |
| Obsidian Geo-Consulting Ltd | Professional & scientific | 2017 |
| Ocean Wealth UK Limited | Financial services | 2018 |
| Oceanbay Property Ltd | Real estate | 2024 |
| Octagon Capital (UK) Ltd | Other services | 2009 |
| Ocumedica Limited | Health & social care | 2012 |
| OEH Limited | Real estate | 2023 |
| Ofena Ltd | Construction | 2019 |
| Office Recycling Solutions (Holdings) Limited | Professional & scientific | 2009 |
| Office Recycling Solutions Limited | Wholesale & retail | 2000 |
| Officeez Ltd | Real estate | 2025 |
| Offprop Investments Ltd | Real estate | 2020 |
| Offset and Counter Trade International Limited | | 1985 |
| OG Forker Construction Ltd | Construction | 2019 |
| Og-Tech Ltd | Information & communication | 2021 |
| Ohlello Properties Limited | Real estate | 2011 |
| OKP Properties Ltd | Real estate | 2023 |
| OKP Worldwide Ltd | Professional & scientific | 2017 |
| OLA Events Ltd | Hospitality | 2025 |
| Old Fallings Playgroup Limited | Education | 2015 |
| Old Rail Farm Limited | Hospitality | 2020 |
| Old School Window Cleaners Ltd | Administrative & support | 2020 |
| Old Veseyans Sports Club Limited | Real estate | 1950 |
| Oldham Fried Chicken Ltd | Wholesale & retail | 2019 |
| Olfnet Ltd | Wholesale & retail | 2023 |