| Namegrace Limited | Construction | 1994 |
| Nancy Florence Ltd | Professional & scientific | 2018 |
| Nazeing Group Limited | Financial services | 2021 |
| Nazeing Heating Limited | Construction | 1977 |
| NC Elite Fitness Ltd | Arts & recreation | 2022 |
| NC Residential Ltd | Real estate | 2022 |
| Nearby Recruitment Ltd | Administrative & support | 2025 |
| Nebula Technologies Limited | Information & communication | 2010 |
| Nelson & Pops Limited | Manufacturing | 2022 |
| Nelsons Brandon Limited | Other services | 2025 |
| Nelsons Broxbourne Limited | Other services | 2026 |
| Nelsons Hitchin Limited | Other services | 2026 |
| Nelsons Holdings (London) Limited | Real estate | 2024 |
| Nelsons Holdings Limited | Financial services | 2018 |
| Nelsons Inc Limited | Financial services | 2020 |
| Nelsons Jackhill Limited | Other services | 2025 |
| Nelsons Racking and Shelving Limited | Construction | 2016 |
| Nelsons Selfstore Limited | Other services | 2016 |
| Nelsons Trading (Online) Limited | Wholesale & retail | 2025 |
| Nelsons Trading Limited | Wholesale & retail | 2018 |
| Nene Riverside Management Company Limited | Households | 2003 |
| Neolux Ltd | Transport & logistics | 2016 |
| Nephro-Urology Clinical Trials Ltd. | Professional & scientific | 2002 |
| Netbrain Limited | Information & communication | 2017 |
| Netengineers Limited | Information & communication | 2014 |
| New Acre Services Limited | Administrative & support | 2017 |
| New Eco Energy Ltd | Real estate | 2021 |
| New Homes Clavering Limited | Real estate | 2022 |
| New Homes Hertfordshire Limited | Real estate | 2020 |
| New Mill Quarter (BL) Resident Management Company Limited | Households | 2017 |
| New Mill Quarter (DWH) Resident Management Company Limited | Households | 2017 |
| New Mill Quarter Estate Resident Management Company Limited | Households | 2017 |
| New Mine House Ltd | Other services | 2022 |
| New River Brewery Ltd | Manufacturing | 2014 |
| New Walton Road Management Limited | Households | 2025 |
| New Zealand Premier Lamb Importers Ltd. | Wholesale & retail | 1982 |
| New Zealand Premier Meat Co. Limited | Wholesale & retail | 1982 |
| Newsom Place (Welwyn Garden City) Management Company Limited | Households | 2003 |
| Newswell (UK) Limited | Professional & scientific | 2003 |
| Newswell Limited | Wholesale & retail | 1965 |
| Newtons Walk Management Company Limited | Households | 2005 |
| Nexalogica Limited | Professional & scientific | 2025 |
| Next Edit Ltd | Information & communication | 2021 |
| Next Level Boiler Solutions Ltd | Construction | 2025 |
| Next Rebel Creative Limited | Information & communication | 2024 |
| Next-Jen Ltd | Professional & scientific | 2020 |
| Nexus (Leytonstone) Management Company Limited | Households | 2005 |
| Nexus 2 Residents Management Limited | Households | 2016 |
| Nexus Recruiting Ltd | Administrative & support | 2023 |
| Niad Buying Office Limited | Extraterritorial | 1965 |
| Nicel Ltd | Real estate | 2017 |
| Nickolds HMO Management & Maintenance Ltd | Households | 2017 |
| Nightingale Gardens (Monyhull NO.2) Management Company Limited | Households | 2005 |
| Nightingale Park (Formby) Residential Management Company Limited | Households | 2026 |
| Nightingale Park Residents Association Limited | Professional & scientific | 2003 |
| Nine Elms Mews Management Company Limited | Households | 2012 |
| NKB Building Services Limited | Construction | 2018 |
| NL Renovation Ltd | Construction | 2018 |
| NO. Twelve Property Limited | Real estate | 2021 |
| Noble Car Centre Limited | Wholesale & retail | 2016 |
| Noma Properties Ltd | Hospitality | 2026 |
| Nomophobia Repairs Ltd | Other services | 2015 |
| Noms's Discoveries Limited | Wholesale & retail | 2023 |
| Nonna's Kitchen UK Ltd | Hospitality | 2021 |
| Nonna's Restaurant Ltd | Hospitality | 2023 |
| Noor Spcie Ltd | Hospitality | 2022 |
| Norman Crossley & Partners Limited | Professional & scientific | 1982 |
| Normis Ltd | Real estate | 2023 |
| North Art Graphic Design Ltd | Professional & scientific | 2019 |
| North Hertfordshire Smiles Limited | Health & social care | 2020 |
| Northaw Estate Management Company Ltd | Administrative & support | 2020 |
| Northcourt Square (Abingdon) Management Company Limited | Households | 2007 |
| Northumberland Park Management Company (Erith) Limited | Households | 1996 |
| Northwood Executive Search Ltd | Administrative & support | 2022 |
| Norton Asset Group Ltd | Financial services | 2024 |
| Norton Hall Meadow Management Limited | Households | 2019 |
| Nostro Group Ltd | Wholesale & retail | 2025 |
| Nottingham Sales and Marketing Ltd | Wholesale & retail | 2024 |
| Nottingham Waterside Management Company Limited | Households | 2015 |
| Nova Satus Projects Ltd | Real estate | 2021 |
| Novanest Capital Ltd | Real estate | 2026 |
| November Alpha Delta Travel Limited | Administrative & support | 2024 |
| Novus (Talbot Road) Estate Management Company Limited | Households | 2019 |
| NSM Commercial Fleet Services Limited | Manufacturing | 2025 |
| NU View Property Ventures Ltd | Real estate | 2024 |
| NU YOU Pilates Limited | Arts & recreation | 2017 |
| Nutburn Meadows Management Limited | Households | 2018 |
| NVB Electrical Ltd | Construction | 2023 |
| O'Ferrall Consultancy Services Limited | Professional & scientific | 2012 |
| Oak Ceramics Limited | Manufacturing | 1999 |
| Oak Leigh Gardens (Barrow) Management Company Limited | Households | 2018 |
| Oakdale Mews (Leeds) Management Company Limited | Households | 1992 |
| Oakhill (Hertford) Limited | Real estate | 1997 |
| Oakhurst (Balsall Common) NO.2 Management Company Limited | Real estate | 2002 |
| Oakleigh Gardens Management Company Limited | Households | 1989 |
| Oakridge Court (South Oxhey) Management Company Limited | Households | 1984 |
| Oakwood Fields Management Company Limited | Households | 2022 |
| Oakwood House Holdings Limited | Real estate | 2023 |
| Oakwood Park Management Company Limited | Households | 2001 |
| Oast House Croft Management Company Limited | Households | 2002 |