| Mystayhomes Limited | Real estate | 2026 |
| Mystockscanner Group Ltd | Information & communication | 2020 |
| Mythical Ltd | Real estate | 2020 |
| N&J Services Limited | Construction | 2021 |
| NAD Security Solutions Ltd | Administrative & support | 2023 |
| Nadi Consulting Ltd | Information & communication | 2016 |
| Naked Recovery Global Limited | Other services | 2009 |
| Nashville Worldwide Ltd | Information & communication | 2021 |
| Nasir.Co Investment Ltd | Real estate | 2019 |
| Natalie Mepham Registered Care Consultancy Ltd | Professional & scientific | 2025 |
| National Highways Safety Services Ltd | Construction | 2022 |
| Natural Fresh Foods Limited | Wholesale & retail | 2011 |
| Nazareth Gardens Residents' Company Limited | Households | 2013 |
| Neptune Media Ltd | Information & communication | 2011 |
| Nera & Aurea Ltd | Wholesale & retail | 2025 |
| Nesbit Lettings Limited | Real estate | 2005 |
| New Foundations Independent Estate Agents Limited | Real estate | 2011 |
| New Romney Holiday Park Ltd | Hospitality | 2021 |
| Newton & Sinclair Ltd | Professional & scientific | 2022 |
| Newton Sinclair Ltd | Real estate | 2021 |
| Nexrock Limited | Information & communication | 2016 |
| Next Eureka Ltd | Hospitality | 2021 |
| NF Consultancy Services Ltd | Real estate | 2021 |
| NF Designs Limited | Professional & scientific | 2017 |
| NF Maltby Property Limited | Real estate | 2025 |
| Nine to Five Properties Limited | Construction | 2011 |
| Ninfield Pizza Ltd | Hospitality | 2025 |
| NIX Joinery Limited | Construction | 2012 |
| Noctis Health Ltd | Arts & recreation | 2026 |
| Norbex Limited | Households | 1960 |
| Normandale House Co. Limited | Households | 1989 |
| North Bridge Consulting Limited | Professional & scientific | 2016 |
| North Coast Wine Warehouse and Lounge Limited | Wholesale & retail | 2018 |
| North Downs Properties Ltd. | Real estate | 2011 |
| North Shore Furniture Limited | Extraterritorial | 2021 |
| Northpalm Limited | Real estate | 2001 |
| Northstar Foundry Ltd | Information & communication | 2026 |
| Nothing Nasty Ltd | Manufacturing | 2020 |
| NP Quinn Property Ltd | Real estate | 2022 |
| NRG Aesthetic Solutions Limited | Health & social care | 2020 |
| NTB2 Solutions Ltd | Professional & scientific | 2025 |
| Number 10 and 11 Rafati Way Management Limited | Households | 2006 |
| Number 23 Ltd | Households | 2024 |
| Nuvola London Trading Limited | Wholesale & retail | 2023 |
| NV Cars Limited | Wholesale & retail | 2023 |
| Nyasha Ltd | Real estate | 2026 |
| O'Hara Happy Homes Limited | Real estate | 2019 |
| Oak Insight Ltd | Professional & scientific | 2021 |
| Oak Tree House Bexhill Limited | Households | 2007 |
| Oakeys Cleaning Limited | Administrative & support | 2014 |
| Oakhurst Place (Bexhill) Management Company Limited | Administrative & support | 2016 |
| Oaklands Global Limited | Financial services | 2013 |
| Oakridge Garage Limited | Wholesale & retail | 2002 |
| Oasis Transformations Auer Ltd | Administrative & support | 2025 |
| Oasis Transformations Burchette Limited | Administrative & support | 2025 |
| Obaoba Ltd | Real estate | 2025 |
| Oblius Ltd | Professional & scientific | 2024 |
| OCB Building Services Ltd | Construction | 2026 |
| Oceanjewel Ltd | Wholesale & retail | 2022 |
| OFF the Hook Meats Ltd | Wholesale & retail | 2022 |
| Offshore Renewable Operations Limited | Construction | 2018 |
| OFI Entertainment Limited | Other services | 2026 |
| OH Crumbs (Sussex) Ltd | Wholesale & retail | 2014 |
| Ohbeze Limited | Professional & scientific | 2021 |
| OIL Installations Limited | Construction | 2003 |
| Old Tools Limited | Wholesale & retail | 2007 |
| Old Town Bistro Limited | Hospitality | 2018 |
| Olive Keys Limited | Real estate | 2020 |
| Olls Investments Limited | Financial services | 2021 |
| OM Luxury Property Ltd | Real estate | 2024 |
| OM Plumbing Ltd | Construction | 2021 |
| Omega Properties Investments Limited | Real estate | 2020 |
| Omni Cure Limited | Professional & scientific | 2013 |
| Omni Lifestyle Limited | Hospitality | 2007 |
| Omni Wealth Limited | Financial services | 2020 |
| ON the Glow Beauty & Aesthetics Ltd | Other services | 2026 |
| Oncert Ltd | Manufacturing | 2013 |
| Onlyfern Ltd | Professional & scientific | 2022 |
| Open Hand Hospitality Ltd | Hospitality | 2015 |
| Orchard Court (Bexhill) Management Ltd | Households | 2008 |
| Orchard Learning Ltd | Other services | 2022 |
| Orchid Beauty Limited | Other services | 2025 |
| Origbemidele Commercial Enterprises Limited | Professional & scientific | 2017 |
| Origin Blank Ltd | Information & communication | 2023 |
| Oryco Ltd | Professional & scientific | 2026 |
| Osga Ltd | Wholesale & retail | 2025 |
| Osom Official Limited | Wholesale & retail | 2018 |
| Osula & Co. Limited | Construction | 2024 |
| Outsource Ability Ltd | Administrative & support | 2023 |
| Oxhey & Knight Holdings Ltd | Financial services | 2025 |
| Oxshott Court RTM Company Limited | Households | 2019 |
| P. Ecom Ltd | Wholesale & retail | 2026 |
| P.O.D Holdings Limited | Real estate | 2017 |
| Pace (13 Amherst Road Freehold) Limited | Households | 2010 |
| Pacenterprise Developments Limited | Other services | 2015 |
| Packman Consultancy Limited | Professional & scientific | 2024 |
| Paleja Properties Ltd | Real estate | 2026 |
| Panacea Skin Solutions Ltd | Health & social care | 2024 |
| Panda Music Ltd | Information & communication | 2023 |
| Pani AM Productions Limited | Information & communication | 2009 |