| Milliner Construction Limited | Construction | 2016 |
| Millmove Limited | Transport & logistics | 1985 |
| Milndale Limited | Professional & scientific | 1993 |
| Mincost Ltd | Wholesale & retail | 2002 |
| Mincost Properties Ltd | Real estate | 2023 |
| Mindful Design Kitchens Limited | Professional & scientific | 2025 |
| Mint Developments Southwest Limited | Hospitality | 2016 |
| Mistral Technical Services Limited | Professional & scientific | 2003 |
| MJM Management Limited | Professional & scientific | 2014 |
| Mkmj Limited | Information & communication | 2009 |
| ML Experts Consulting Ltd | Professional & scientific | 2015 |
| MLJ Plumbing & Heating Ltd | Construction | 2012 |
| MLJ Site Services Limited | Construction | 2026 |
| Mobile Tool Sales Ltd | Wholesale & retail | 2018 |
| Momentum Design Ltd | Professional & scientific | 2021 |
| Momo Talent Limited | Administrative & support | 2025 |
| Montpellier Capital Ltd | Real estate | 2022 |
| Moscrop Site Service Limited | Manufacturing | 2021 |
| Motionsense Ltd | Information & communication | 2024 |
| Motor Services of Chepstow Limited | Wholesale & retail | 2004 |
| Motortorque Tunning Limited | Wholesale & retail | 2025 |
| MP Masonry Contractors Ltd | Construction | 2021 |
| MSB Steel Limited | Construction | 2018 |
| Muddy Pups Dog Walking and Pet Service Ltd | Agriculture & fishing | 2022 |
| Multi Taskers Limited | Professional & scientific | 2013 |
| Multisoft UK Limited | Information & communication | 1998 |
| Murphy Connor Ltd | Hospitality | 2017 |
| Mustoes Limited | Wholesale & retail | 2026 |
| Naas Court Farm Limited | Real estate | 2020 |
| Nano Intelligent Textiles Ltd | Professional & scientific | 2018 |
| Naomi's Aesthetics & Training Ltd | Agriculture & fishing | 2025 |
| Nautico Properties Ltd | Real estate | 2025 |
| New Century Research & Development Ltd | Financial services | 2023 |
| New Energy Partnership (Hold Co) Limited | Energy | 2022 |
| New Energy Partnership Limited | Professional & scientific | 2022 |
| New Inn (Ross Road) Ltd | Hospitality | 2023 |
| New Weir Carparks Limited | Real estate | 2008 |
| Newsham Tax Ltd | Professional & scientific | 2013 |
| Newspace Containers Limited | Manufacturing | 2000 |
| Nexfah Technology Solutions Limited | Information & communication | 2023 |
| Nexlab Scientific Ltd | Wholesale & retail | 2025 |
| Nexus Payments Ltd | Financial services | 2018 |
| Nick Hill Services Limited | Other services | 2013 |
| Njurabuild Limited | Construction | 2013 |
| Njurastone Limited | Manufacturing | 2013 |
| NO 223 Limited | Agriculture & fishing | 2024 |
| North Oaks Developments Limited | Construction | 2007 |
| Northern United Engineering (Cinderford) Limited | Wholesale & retail | 1967 |
| Northwood Build Limited | Construction | 2021 |
| Noslen Limited | Information & communication | 2026 |
| Nrqs Ltd | Professional & scientific | 2023 |
| Nutmill Limited | Real estate | 2014 |
| Nuvio Labs Nutrition Ltd | Wholesale & retail | 2025 |
| Nwfirefitness Ltd | Other services | 2017 |
| O'Neill & Brennan Site Services Limited | Water & waste | 2002 |
| Oakdean Carpentry & Creations Ltd | Manufacturing | 2025 |
| Oakdean Landscapes Limited | Administrative & support | 2003 |
| Oakenhill Environmental Limited | Administrative & support | 2022 |
| Oakwood Vale Lodges Ltd | Administrative & support | 2017 |
| Ofisa Limited | Real estate | 2020 |
| Old Chapel Wesley Road Management Company Limited | Administrative & support | 2009 |
| Operational Safety Services Limited | Professional & scientific | 2019 |
| Optimum Energy Solutions Ltd | Professional & scientific | 2018 |
| Optimum Mortgages Limited | Financial services | 2016 |
| ORB Alpha Co Ltd | Construction | 2021 |
| ORB Beta Co Ltd | Construction | 2021 |
| ORB Delta Co Ltd | Construction | 2021 |
| ORB Development Consulting Limited | Administrative & support | 2016 |
| ORB Development Group Ltd | Financial services | 2024 |
| ORB Developments Limited | Construction | 2016 |
| ORB Property Development Limited | Construction | 2013 |
| Orchard Convenience Stores Limited | Wholesale & retail | 2023 |
| Orion Imaging Limited | Information & communication | 1995 |
| Ortley House Consulting Ltd | Professional & scientific | 2021 |
| Osprey Compliance Services Limited | Professional & scientific | 2015 |
| Other Way Consulting Ltd | Professional & scientific | 2022 |
| OUR Last Hour Film Ltd | Information & communication | 2025 |
| Outdoor Medical Solutions (Holdings) Ltd | Financial services | 2020 |
| Outdoor Medical Solutions Limited | Health & social care | 2010 |
| Outdoorology Ltd | Wholesale & retail | 2023 |
| OW Design Engineering Ltd | Professional & scientific | 2024 |
| P. Hurcomb Carpentry & Building Ltd | Manufacturing | 2022 |
| Padumi Holdings Limited | Professional & scientific | 1995 |
| PAG UK Holdings Ltd | Financial services | 2025 |
| Paine and Stewart Limited | Administrative & support | 2007 |
| Parallel Precision Limited | Manufacturing | 2016 |
| Park Hall Grange Ltd | Construction | 2021 |
| Parkend Club Limited | Arts & recreation | 2015 |
| Parkend Shop and Café Ltd | Wholesale & retail | 2023 |
| Parmenion Sports Management Limited | Arts & recreation | 2021 |
| Pasfab Limited | Manufacturing | 2001 |
| Passiframe Limited | Construction | 2016 |
| Patrick Molyneux Ltd | Information & communication | 2007 |
| Patstrand Limited | Professional & scientific | 1979 |
| Paul Williams Plumbing & Heating Limited | Construction | 2012 |
| PEARCE3D Ltd | Professional & scientific | 2015 |
| Pearson's Woodhouse & Campers Ltd | Wholesale & retail | 2023 |
| Peter Briscoe Limited | Manufacturing | 2014 |
| Peter Gwynne & Co Ltd. | Real estate | 1976 |
| PG Ropework Limited | Professional & scientific | 2025 |