| New World Carpenters Limited | Construction | 2017 |
| Newbury Close Management Company Limited | Households | 2003 |
| Newdawn Technology Ltd | Information & communication | 2022 |
| Newhall Physiotherapy Ltd | Health & social care | 2026 |
| Newlands Court Harrow RTM Company Limited | Households | 2012 |
| Newman Interior Services Limited | Construction | 2018 |
| Newmed Pharma Ltd | Wholesale & retail | 2024 |
| Newmet Limited | Manufacturing | 1947 |
| Newmet Properties Limited | Real estate | 2002 |
| Newton Associates (Surveyors) Limited | Professional & scientific | 2003 |
| Newton Jones Limited | Households | 2003 |
| Newton Scientific Ltd | Manufacturing | 2020 |
| Newtons Property Solutions Ltd | Construction | 2018 |
| Newtown Cars Harlow Ltd | Wholesale & retail | 2015 |
| Nexlink Reborn Limited | Wholesale & retail | 2025 |
| Nexon Builders Ltd | Construction | 2025 |
| Next Bridge Systems Ltd | Wholesale & retail | 2026 |
| Next GEN Community CIC | Education | 2025 |
| Next Generation Sensors Ltd | Information & communication | 2025 |
| Next Transport & Auto Limited | Wholesale & retail | 2025 |
| Nextage Hub Ltd | Wholesale & retail | 2025 |
| Nextgen Logistics Ltd | Transport & logistics | 2021 |
| Nextkey Properties Limited | Real estate | 2025 |
| Nexus Research Partners Ltd | Professional & scientific | 2024 |
| Nezoneh Ltd | Wholesale & retail | 2021 |
| NFG Medical Ltd | Health & social care | 2021 |
| Ngozi Okeke Ltd | Health & social care | 2024 |
| Nhost Ltd | Information & communication | 2016 |
| NI Medical Limited | Health & social care | 2024 |
| Niarbyl Ltd | Administrative & support | 2012 |
| Nibus Consults Limited | Health & social care | 2015 |
| Nicholas James Home Improvements Limited | Construction | 2013 |
| Nickel Electrical Services Ltd | Construction | 2024 |
| Nicola Massier Ltd | Professional & scientific | 2018 |
| Nicolas&Co Ltd | Construction | 2026 |
| Nicopharm Limited | Wholesale & retail | 2024 |
| Nicutrans Ltd | Transport & logistics | 2015 |
| Nierzwicki Trans Limited | Transport & logistics | 2018 |
| Nigerian Doctors in the UK | Administrative & support | 2020 |
| Nigerian Swindon Muslim Community (Nsmc) Limited | Health & social care | 2025 |
| Nightingales Area H74 Haydon Wick Management Company Limited | Households | 2005 |
| Nigi Homes Ltd | Real estate | 2022 |
| Nilemed Ltd | Health & social care | 2024 |
| Nimo Catering Limited | Hospitality | 2018 |
| Nine Lives Design Ltd | Other services | 2020 |
| Nirbas Services Limited | Information & communication | 2025 |
| Niros Sorin Limited | Transport & logistics | 2018 |
| Nisabella Limited | Wholesale & retail | 2014 |
| Nissi Domestic & Cleaning Services Ltd | Administrative & support | 2022 |
| Nixon House RTM Company Limited | Households | 2016 |
| Niyochi Property Group Ltd | Real estate | 2020 |
| Njbe Ltd | Health & social care | 2024 |
| NJC Social Limited | Transport & logistics | 2024 |
| Njlrail Ltd | Professional & scientific | 2022 |
| NJS Cars Ltd | Transport & logistics | 2006 |
| NJW Cleaning Services Ltd | Administrative & support | 2021 |
| NK Move Ltd | Professional & scientific | 2025 |
| NKZ Properties Ltd | Real estate | 2020 |
| NLB Engineering NA Limited | Wholesale & retail | 2015 |
| NLF Company Ltd | Health & social care | 2025 |
| NLG Construct Ltd | Construction | 2026 |
| NN Legal Limited | Professional & scientific | 2026 |
| NO Name Plant Ltd | Construction | 2013 |
| NO Short Rests Ltd | Information & communication | 2025 |
| NO Slacking Clothing Ltd | Wholesale & retail | 2024 |
| NO Slacking Ltd | Manufacturing | 2019 |
| NO Weapon Drylining Ltd | Construction | 2026 |
| NO. 2 Eccleston Square Tenant's Association Limited | Households | 1968 |
| NO.81 Ltd | Other services | 2020 |
| Noa's Consulting & Solutions Ltd. | Information & communication | 2017 |
| Nobel LUX Ltd | Construction | 2022 |
| Noble Meadows Properties Ltd | Real estate | 2026 |
| Noble Standard Care Limited | Administrative & support | 2024 |
| Noblefar Limited | Other services | 2016 |
| Nobody Gets OUT Sober Ltd | Hospitality | 2023 |
| Nobtec Ltd | Information & communication | 2020 |
| NOD Chris Limited | Health & social care | 2024 |
| Noir & Fier Capital Limited | Financial services | 2021 |
| Noira Luxe Limited | Wholesale & retail | 2025 |
| Non-Branded Limited | Wholesale & retail | 2022 |
| Nongor Ltd | Health & social care | 2023 |
| Noor Healthcare Ltd | Health & social care | 2021 |
| Nooramina Medics Ltd | Health & social care | 2026 |
| Noralin Ltd | Construction | 2015 |
| Nordline Accounting Ltd | Professional & scientific | 2025 |
| Norfolk House Management (Leeds) Limited | Households | 1998 |
| Norfolk Medics Limited | Health & social care | 2026 |
| Norgate Properties Ltd | Real estate | 2024 |
| Norlah Medical Solutions Limited | Health & social care | 2026 |
| Norris Trading Ltd | Wholesale & retail | 2025 |
| North Abingdon Management Company Limited | Households | 2022 |
| North East Demolition (UK) Ltd | Construction | 2004 |
| North Lodge RTM Company Ltd | Households | 2014 |
| North Star House RTM Company Limited | Households | 2009 |
| North Street Shop Ltd | Information & communication | 2020 |
| North Weald & District Miniature Railway Holdings Limited | Transport & logistics | 2022 |
| North Weald Aviation Group Limited | Education | 2026 |
| North Weald Nursery Limited | Wholesale & retail | 2001 |
| North West Quartet Estate Management Company Limited | Households | 2022 |
| North Wood Furniture Ltd | Wholesale & retail | 2022 |