| My Acorn Haulage Ltd | Transport & logistics | 2026 |
| N Shahi Ltd | Hospitality | 2023 |
| N&C Property Solutions Ltd | Construction | 2018 |
| N. H. Jones & Sons Limited | Construction | 2006 |
| N.B. Jones Electrical Services Limited | Construction | 2014 |
| N.E. Fasteners Limited | Wholesale & retail | 1985 |
| Nahal Real Estate Limited | Construction | 2020 |
| Nail Training Academy Ltd | Other services | 2018 |
| Naptex Limited | Administrative & support | 2004 |
| Nathan Dyke Ltd | Construction | 2024 |
| Nathan Langston Ltd | Real estate | 2026 |
| National Food Machinery Services Ltd | Wholesale & retail | 2017 |
| NB Autos Limited | Wholesale & retail | 2008 |
| NB Marketing Consulting Ltd | Information & communication | 2026 |
| NBC Property Master Limited | Financial services | 2016 |
| ND Plant Holdings Ltd | Administrative & support | 2026 |
| ND Plastering Specialists Ltd | Construction | 2022 |
| NE56 Holdings Ltd | Financial services | 2025 |
| Neat N Tidy Gardens Limited | Administrative & support | 2021 |
| Neil Salvidge Td&A Ltd | Professional & scientific | 2018 |
| Neil Westwood Roofing & Building Limited | Construction | 2007 |
| Nest Property Partnership Limited | Real estate | 2019 |
| Nestor Kendrick Properties Limited | Real estate | 2021 |
| Netray UK Limited | Wholesale & retail | 2024 |
| Nettsafe Ltd | Construction | 2017 |
| New 1ST Class Trims Ltd | Other services | 2025 |
| New Chapter Property Consultants Ltd | Real estate | 2018 |
| New Mona Enterprise Limited | Wholesale & retail | 2023 |
| Newdale Properties (Dudley) Limited | Real estate | 2022 |
| Newline Plumbing & Heating Supplies Limited | Wholesale & retail | 1986 |
| Next GEN Makers Limited | Education | 2018 |
| Nextgen Safety Ltd | Manufacturing | 2002 |
| Nexus Quality Services Limited | Professional & scientific | 2023 |
| NGJ Midlands Ltd | Wholesale & retail | 2017 |
| Nice Tips Nail Salon Ltd | Other services | 2023 |
| Nicholls Properties Ltd | Real estate | 2016 |
| Nicklin Electrical Contracting Limited | Construction | 2015 |
| Nigel COX Butchers Limited | Wholesale & retail | 2014 |
| Ninety Eight Cleaning Services Ltd | Administrative & support | 2024 |
| Nipper D Limited | Financial services | 2025 |
| NKM Homes Ltd | Real estate | 2024 |
| NL & L Ltd | Financial services | 2025 |
| NO 10 Hairdressers Limited | Other services | 2003 |
| NO4 Bar Limited | Hospitality | 2022 |
| Northampton General Partner Limited | Extraterritorial | 2005 |
| Northampton Shopping Centre Limited Partnership | | 2005 |
| Northgate Restaurants Ltd | Hospitality | 2001 |
| NOT BAD Yaself Ltd | Wholesale & retail | 2025 |
| Nova Design and Management Limited | Financial services | 1988 |
| Nova Design Ltd | Professional & scientific | 2011 |
| Nova Phoenix Limited | Professional & scientific | 2014 |
| Novella Craft & Cocktails Ltd | Hospitality | 2019 |
| NP Optics Ltd | Financial services | 2024 |
| NSH Consultancy Limited | Information & communication | 2022 |
| Nsph Consulting Ltd | Education | 2025 |
| NSW Bespoke Joinery Ltd | Manufacturing | 2024 |
| NT GAS Services Limited | Other services | 2018 |
| Number 37 Design & Print Ltd | Other services | 2006 |
| Nutricise Ltd | Administrative & support | 2010 |
| NW Scaffolding Services Ltd | Construction | 2026 |
| Ny's Nails UK Ltd | Other services | 2019 |
| NYS Butterflies Ltd | Other services | 2022 |
| Nyss Stores Ltd | Wholesale & retail | 2013 |
| O C L Kingswinford Limited | Wholesale & retail | 2001 |
| O'Neill Electrical Services Ltd | Construction | 2020 |
| O.L.D. Waste & Consultancy Ltd | Water & waste | 2017 |
| Oakham Construction Limited | Construction | 2010 |
| Oakham Holdings (Midlands) Limited | Financial services | 2020 |
| Oakham Property Limited | Construction | 2020 |
| Oakholme Limited | Hospitality | 2019 |
| Oakmast Limited | Professional & scientific | 2004 |
| Oakmoor Holdings Ltd | Real estate | 2017 |
| Oakridge Surveying Limited | Professional & scientific | 2026 |
| OB & B Limited | Extraterritorial | 2016 |
| Octopus Contract Furniture Ltd | Wholesale & retail | 2024 |
| Oddguide Limited | Wholesale & retail | 1976 |
| OGB Services Limited | Hospitality | 2020 |
| OH My HUR Limited | Other services | 2020 |
| OML Coaching Limited | Professional & scientific | 2026 |
| Omnay Properties Limited | Construction | 2004 |
| Omnia Clinical Academy Limited | Health & social care | 2024 |
| Omnia Clinical Group Limited | Financial services | 2024 |
| Omnia Clinical Wholesale Limited | Health & social care | 2023 |
| One Cat at a Time Community Interest Company | Other services | 2025 |
| Onyx Utilities Ltd | Construction | 2016 |
| Open Protocol Technology Limited | Construction | 2008 |
| Open Technologies Consulting Limited | Information & communication | 2009 |
| Optimus Auto's Ltd | Wholesale & retail | 2025 |
| Osborne Game Services Ltd | Administrative & support | 2023 |
| Oscar Property Holdings Ltd | Real estate | 2026 |
| OUR MAN in the Fifth Ltd | Information & communication | 2024 |
| Outdoor Creation (Holdings) Limited | Financial services | 2008 |
| Outwood Ventures Ltd | Financial services | 2023 |
| OWL Heating Limited | Construction | 2007 |
| Oxfordshire Sportflying Limited | Arts & recreation | 1982 |
| P & N Property & Renovations Ltd | Real estate | 2025 |
| P J Forrest (Transport) Limited | Transport & logistics | 2014 |
| P K Consulting (West Midlands) Ltd | Transport & logistics | 2011 |
| P R Allen (Midlands) Ltd | Administrative & support | 2007 |
| P Rushton Building Contractors Ltd | Construction | 2021 |