| Neon Diagnostics Ltd | Wholesale & retail | 2011 |
| Neon Monster Ltd | Arts & recreation | 2021 |
| Neu-Pcb Ltd | Professional & scientific | 2024 |
| New Dawn Solutions Limited | Professional & scientific | 2024 |
| New Image Home Improvements Ltd | Construction | 2026 |
| New Land Street R Ltd | Wholesale & retail | 2024 |
| New Millennium Care Limited | Administrative & support | 2014 |
| New Road Accountants Limited | Professional & scientific | 2023 |
| New Street Developments Limited | Real estate | 2013 |
| New Tanning Lounge Ltd | Other services | 2023 |
| New Wine Holdings Limited | Real estate | 2020 |
| Newland Lettings Ltd | Real estate | 2021 |
| Newman Accountancy Services Ltd | Professional & scientific | 2010 |
| Newmanhuis Property Management Limited | Real estate | 2017 |
| Next Day Consulting Ltd | Professional & scientific | 2018 |
| Nexus Audio Ltd | Wholesale & retail | 2022 |
| NHL Properties Ltd | Real estate | 2016 |
| Niche & Clean Ltd | Administrative & support | 2025 |
| Niche Serviced Apartments Ltd | Real estate | 2017 |
| Niche Training Ltd | Education | 2023 |
| Nicholas Court Residents Management Company Limited | Administrative & support | 2002 |
| Nitrotrader Ltd | Financial services | 2025 |
| Nj&B Investments Limited | Construction | 2017 |
| NO38-REC Ltd | Professional & scientific | 2024 |
| Noakes Cross Consultancy Ltd | Administrative & support | 2017 |
| Nordfel Limited | Other services | 2018 |
| Norfolk Internet Services Limited | Professional & scientific | 1995 |
| North Yorkshire Internet Services Limited | Professional & scientific | 1995 |
| Northamptonshire Internet Services Limited | Professional & scientific | 1995 |
| Northgate Homes Ltd | Administrative & support | 2025 |
| Northgate Waste Services Ltd | Water & waste | 2025 |
| Nossewej Gundogs Limited | Education | 2021 |
| Nossewej Limited | Wholesale & retail | 2015 |
| NOT an Ostrich Ltd | Professional & scientific | 2015 |
| Notley Farming LLP | | 2018 |
| Notthistruck.Co Ltd | Wholesale & retail | 2024 |
| Nottinghamshire Internet Services Limited | Professional & scientific | 1995 |
| Nova Automotive Group Ltd | Wholesale & retail | 2023 |
| Nova Vita Homes Ltd | Health & social care | 2026 |
| Novaplas Limited | Manufacturing | 2004 |
| Novr Energy Ltd | Construction | 2025 |
| Novr Group Ltd | Financial services | 2025 |
| NPC Electrical Services Limited | Construction | 2006 |
| Nugara Ltd | Information & communication | 2014 |
| Numina Developments Limited | Real estate | 2026 |
| Numina Limited | Financial services | 2025 |
| Nuts About Magic Ltd | Wholesale & retail | 2020 |
| Nutsncones Seeds Limited | Wholesale & retail | 2016 |
| NWP Minerals Limited | Mining & quarrying | 2018 |
| Oak Stores 2017 Ltd | Wholesale & retail | 2024 |
| Oakley Carpentry Limited | Construction | 2012 |
| Oakmarenna Ltd | Manufacturing | 2025 |
| Obligate Ltd | Information & communication | 2016 |
| Observation Attractions Company Ltd | Arts & recreation | 2021 |
| OC Fire & Security Ltd | Administrative & support | 2024 |
| Occlude Drainage Solutions Limited | Water & waste | 2020 |
| Octadoodle Ltd | Information & communication | 2022 |
| Odnm Stone Ltd | Construction | 2022 |
| ODO Floors Ltd | Construction | 2024 |
| OEM Controls Limited | Wholesale & retail | 2018 |
| Olivia Jack Estates Ltd | Real estate | 2020 |
| Olivia Jack Limited | Real estate | 2020 |
| Oloye Buildings Ltd | Construction | 2023 |
| ON Tine Capital Limited | Real estate | 2018 |
| One Environmental (Group Holdings) Ltd | Professional & scientific | 2019 |
| One Environmental (Midlands) Ltd | Construction | 2023 |
| One Environmental GAS Ltd | Construction | 2019 |
| One Environmental Interiors Ltd | Construction | 2018 |
| One Environmental Ltd | Construction | 2010 |
| One Environmental Pumps Ltd | Other services | 2016 |
| Onestep Social Marketing Limited | Other services | 2019 |
| Ongar Building Services Limited | Administrative & support | 2004 |
| Onside Therapy and Performance Ltd | Health & social care | 2025 |
| Onyekason World Limited | Health & social care | 2020 |
| Open Path Wellbeing CIC | Health & social care | 2026 |
| Opera Luna Tattoo Limited | Arts & recreation | 2016 |
| Optimise Health & Wellbeing Ltd | Education | 2024 |
| Orsett Quarry Limited | Mining & quarrying | 1994 |
| Oulton Hall Limited | Households | 2021 |
| OUT Safe Ltd | Water & waste | 2026 |
| Outside Office Ltd | Hospitality | 2025 |
| Overton Holdings Ltd | Financial services | 2018 |
| Owls Management Group Limited | Administrative & support | 2025 |
| Oxfordshire Internet Services Limited | Professional & scientific | 1995 |
| Ozmium Global Ltd | Wholesale & retail | 2020 |
| P J H Cable Jointing Limited | Construction | 2008 |
| P&J Hudson Ltd | Financial services | 2025 |
| P3M Services UK Ltd | Information & communication | 2019 |
| P9 Security Solutions Ltd | Administrative & support | 2024 |
| Pacepoint Logistics Ltd | Transport & logistics | 2025 |
| Paisley Internet Services Limited | Professional & scientific | 1995 |
| Pajmay & Associates Ltd | Education | 2024 |
| Pamela Dowie Design Limited | Information & communication | 2010 |
| Panda Internet Limited | Information & communication | 2021 |
| Pandalus Consultancy Limited | Professional & scientific | 2015 |
| Panthere Limited | Professional & scientific | 2022 |
| Paoletti UK Limited | Real estate | 2014 |
| Paspective Ltd | Wholesale & retail | 2023 |
| Paton & LEE Ltd | Professional & scientific | 2015 |
| Paul Alan Clark Limited | Manufacturing | 2014 |