| Nova Peak Limited | Information & communication | 2022 |
| Novemo Ltd | Information & communication | 2015 |
| Novus Group Limited | Professional & scientific | 2001 |
| Novus Networks Limited | Wholesale & retail | 1999 |
| NOX Security Limited | Administrative & support | 2008 |
| NPC Services Ltd | Financial services | 2017 |
| NPLUS1 Environmental Limited | Agriculture & fishing | 2024 |
| Npsh Limited | Professional & scientific | 2011 |
| NQ Leisure Group Limited | Hospitality | 2023 |
| NR 65 Ltd. | Professional & scientific | 2003 |
| NRG Associates (UK) Limited | Health & social care | 2003 |
| NSA Electrical Services Ltd | Construction | 2023 |
| NSJ Contractors Ltd | Construction | 2002 |
| NSJ Developments Limited | Construction | 2022 |
| NSJ Holdings Limited | Financial services | 2021 |
| NSS 1.1 Ltd | Financial services | 2017 |
| NSS 1.2 Ltd | Financial services | 2017 |
| Nuabee Limited | Information & communication | 2025 |
| Nude Luxe Limited | Wholesale & retail | 2025 |
| Nuforte Ltd | Health & social care | 2006 |
| Null Limited | Information & communication | 2015 |
| Nurture Earth School Ltd | Education | 2022 |
| Nurturing Minds AI Ltd | Information & communication | 2025 |
| Nutrigain Limited | Manufacturing | 2006 |
| NW Care Education Limited | Education | 2025 |
| NW Care Group (Holdings) Limited | Financial services | 2026 |
| NW Care Group Limited | Health & social care | 2024 |
| NW Care Property Ltd | Real estate | 2025 |
| NW Care West Lancs Limited | Education | 2026 |
| NXL Holdings Limited | Financial services | 2022 |
| O K Diner Franchising Limited | Professional & scientific | 2007 |
| O K Diners Limited | Hospitality | 1963 |
| O&J Contracting Limited | Agriculture & fishing | 2019 |
| O&L Property Management Limited | Real estate | 2023 |
| Oak & Ember Outdoor Living Ltd | Administrative & support | 2026 |
| Oak Court RTM Company Limited | Households | 2023 |
| Oakbank Court (Bollington) Management Limited | Households | 1999 |
| Oakenbank Building Ltd | Construction | 2024 |
| Oakenbank Construction Ltd | Construction | 2024 |
| Oakenbank Joinery & Build Ltd | Construction | 2024 |
| Oakford Court Hadfield RTM Company Limited | Households | 2016 |
| Oakhare Group Ltd | Financial services | 2025 |
| Oakhare Properties Limited | Real estate | 2017 |
| Oakhaven Developments Limited | Construction | 2025 |
| Oaklands (Oxton) Management Company Limited | Households | 1993 |
| Oakridge Court Ltd | Real estate | 2022 |
| Oaktree Frames Ltd | Administrative & support | 2020 |
| Oakwood Energy and Environment Ltd | Professional & scientific | 2011 |
| Oakwood Estates & Lettings Limited | Real estate | 2026 |
| OAW Solutions Limited | Information & communication | 2026 |
| OBI Dog Ltd | Information & communication | 2014 |
| OBL Academy Limited | Education | 2025 |
| Obsidian Design & Build Ltd | Construction | 2023 |
| OBSIDIAN55 Ltd | Real estate | 2025 |
| OC328211 LLP | | 2007 |
| Ocean Blue Lettings Limited | Real estate | 2017 |
| Octavia Luxury Holdings Limited | Financial services | 2021 |
| Oculto Ltd | Wholesale & retail | 2025 |
| Odasco Limited | Professional & scientific | 2019 |
| Odem Plumbing & Heating Ltd | Construction | 2025 |
| Offleash Dog Training Ltd | Wholesale & retail | 2024 |
| OFO Energy Limited | Professional & scientific | 2023 |
| OH Five Ltd | Information & communication | 2024 |
| OH Honey Ltd | Wholesale & retail | 2019 |
| OH Properties Limited | Real estate | 2026 |
| OIE DES Neiges Limited | Hospitality | 2014 |
| OK Goods UK Ltd | Wholesale & retail | 2025 |
| Old Lansdowne 71-73 Limited | Real estate | 2019 |
| Old Time Straps Ltd | Wholesale & retail | 2025 |
| Oldham Food Hall Limited | Hospitality | 2019 |
| Olive Open Kitchen Ltd | Hospitality | 2023 |
| Oliver Lowe Developments Limited | Real estate | 2024 |
| Oliver Walmsley Limited | Information & communication | 2025 |
| Oliver Webb Racing LLP | | 2011 |
| Olivia Jade Ltd | Other services | 2025 |
| Olom Property Ltd | Real estate | 2026 |
| Oltre Marketing Limited | Administrative & support | 2022 |
| Olumide Galleries Ltd | Wholesale & retail | 2016 |
| Olympus Trading Ltd | Wholesale & retail | 2024 |
| Omas Northern Europe Limited | Wholesale & retail | 2024 |
| Omne Group Ltd | Health & social care | 2025 |
| Omninest Ltd | Wholesale & retail | 2025 |
| Omnis Global Ltd | Real estate | 2018 |
| OMO Rose Limited | Wholesale & retail | 2023 |
| Omohthompson Global Services Ltd | Other services | 2019 |
| ON the Move Again Limited | Transport & logistics | 2021 |
| ON VIC Corporation Ltd | Administrative & support | 2017 |
| Onclaims Limited | Professional & scientific | 2000 |
| ONCLOUD9-SOFAS Limited | Extraterritorial | 2025 |
| Oncology Access Solutions Ltd | Professional & scientific | 2023 |
| One Beauty Cheshire Limited | Other services | 2025 |
| One Project Macclesfield Community Interest Company | Agriculture & fishing | 2021 |
| Online CBT Services Limited | Health & social care | 2026 |
| Online Stoves and Fires Ltd | Wholesale & retail | 2024 |
| Only Option Clothing Ltd | Wholesale & retail | 2026 |
| Onperson International Limited | Information & communication | 2005 |
| Onsiteintelligence. Ltd | Information & communication | 2026 |
| Onward Enterprises Limited | Real estate | 1999 |
| Onyx Luxury Developments Ltd | Construction | 2025 |
| Ooglite Ltd | Wholesale & retail | 2022 |