| MDG Builders Limited | Construction | 2018 |
| Me-Ol-Bamboo Ltd | Wholesale & retail | 2019 |
| Mead Plant Limited | Wholesale & retail | 2023 |
| Meadow Close (Clophill) Management Company Limited | Real estate | 2020 |
| Mechanically Minded MAN Ltd | Manufacturing | 2025 |
| Melem Limited | Real estate | 2017 |
| Meppershall Village Hall Limited | Other services | 2014 |
| MF Services Ltd | Wholesale & retail | 2003 |
| Mike Todd Consultancy Ltd | Professional & scientific | 2025 |
| Millenium Scaffolding and Cradles Limited | Administrative & support | 2008 |
| Millenium Scaffolding Properties Limited | Administrative & support | 2015 |
| Mindset the Mayhem Coaching Limited | Other services | 2023 |
| Mobelle Home Care Limited | Health & social care | 2015 |
| Modo Mobi Ltd | Information & communication | 2018 |
| Moffat Engineering Services Ltd | Professional & scientific | 2022 |
| More Than Talking Limited | Education | 2014 |
| Morley Biopharma Consulting Ltd | Professional & scientific | 2024 |
| Mortgage Quest Hitchin Limited | Financial services | 2012 |
| Mortgageup Ltd | Financial services | 2020 |
| Mount Pleasant Park (Tamworth) Limited | Extraterritorial | 1978 |
| Movement Films Ltd | Information & communication | 2019 |
| MR Amenity Limited | Wholesale & retail | 2017 |
| MR Homespace Ltd | Real estate | 2021 |
| MRL Electrical Installations Limited | Construction | 2019 |
| MSA Catering Ltd | Hospitality | 2024 |
| My Hemp Store Ltd | Extraterritorial | 2020 |
| N & P Windows Limited | Construction | 1987 |
| Nagore Ltd | Public administration | 2018 |
| NC Supplies Ltd | Professional & scientific | 2021 |
| Neamtu & Tiles Ltd | Construction | 2018 |
| Nemesis Technologies Limited | Information & communication | 1996 |
| New Build Snag & Co Ltd | Construction | 2025 |
| New Kitchens Limited | Wholesale & retail | 1971 |
| New Vista Homes Limited | Construction | 2020 |
| New Water Technologies Ltd | Construction | 2018 |
| New YEW Hair Ltd | Administrative & support | 2015 |
| Nextgen Property Investors Ltd | Hospitality | 2024 |
| Nick Kane Analytical Limited | Professional & scientific | 2015 |
| Nicola Brady Consultancy Services Ltd | Professional & scientific | 2024 |
| NJF Construction Limited | Construction | 2002 |
| Northern Monkee Ltd | Households | 2023 |
| Novmbr Limited | Wholesale & retail | 2016 |
| Nsmart Consulting Ltd | Professional & scientific | 2026 |
| Nursery Online Limited | Professional & scientific | 2007 |
| O & M Quality Properties Ltd | Real estate | 2024 |
| O Shotubo Consulting Ltd | Information & communication | 2022 |
| Oak House One Ltd | Health & social care | 2026 |
| Oakfield Executive Homes Limited | Construction | 2008 |
| Oasis Dwellings Ltd | Real estate | 2021 |
| Ocml Properties Ltd | Real estate | 2021 |
| Once Upon a Perfect Party Ltd | Hospitality | 2023 |
| One Dragonfly Limited | Education | 2023 |
| One Stop Plumbing and Aftercare Services Ltd | Construction | 2025 |
| One Village Support Limited | Professional & scientific | 2025 |
| Original Beer House Limited | Hospitality | 2012 |
| Osay Advisers Ltd | Professional & scientific | 2023 |
| Ous&Barham Limited | Transport & logistics | 2020 |
| Overwatch Project Management Ltd | Professional & scientific | 2014 |
| OWL Management Services Ltd | Professional & scientific | 2025 |
| P J Kelly Electrical Limited | Construction | 2015 |
| P-Maps Limited | Administrative & support | 2005 |
| Panoramic Systems Limited | Information & communication | 2011 |
| Passion for Granite Ltd | Manufacturing | 2020 |
| Pathfinder Legal Services Limited | Professional & scientific | 2014 |
| Pedley Lane Management Co Ltd | Households | 2018 |
| Pendring Limited | Hospitality | 1979 |
| Percentage IT Limited | Information & communication | 2012 |
| Performance & Transformation Consulting Ltd | Professional & scientific | 2021 |
| Pest Reports Pro Ltd | Information & communication | 2024 |
| Peta David Ltd | Professional & scientific | 2022 |
| Philip Atherton Consulting Limited | Professional & scientific | 2015 |
| Phillip Rance Limited | Water & waste | 2020 |
| PHO Boyle Limited | Real estate | 2024 |
| Pineapple Park Limited | Manufacturing | 1993 |
| Pioneer Rally Company Limited | Wholesale & retail | 2025 |
| Planlift Ltd | Professional & scientific | 2026 |
| Plum and Honey Skin Ltd | Other services | 2025 |
| Podium Systems Limited | Information & communication | 2021 |
| Polehanger Farms Limited | Agriculture & fishing | 1970 |
| Polyalfa Drainage Systems Ltd | Professional & scientific | 2006 |
| Polyalfa Ltd | Professional & scientific | 2006 |
| Polyline Drainage Systems Limited | Professional & scientific | 1989 |
| Precise Carpentry Limited | Administrative & support | 2014 |
| Premier County Hire (PCH) Ltd | Construction | 2021 |
| Premier Properties (Anglia) LLP | | 2008 |
| Principlanning Ltd | Professional & scientific | 2024 |
| Propafit Interiors Ltd | Manufacturing | 2021 |
| PSC Media Limited | Administrative & support | 2024 |
| Psychometrics Ltd | Professional & scientific | 1989 |
| Pyromusical Productions Ltd | Arts & recreation | 2026 |
| Q.E.N.A Care Ltd | Health & social care | 2022 |
| Quality Fire Protection Group Ltd | Wholesale & retail | 2023 |
| Quantum Design Limited | Professional & scientific | 1994 |
| R Burton and Family Properties Limited | Administrative & support | 2015 |
| R&R Commercial Services Ltd | Wholesale & retail | 2020 |
| R.A.Rodriguez (U.K.) Limited | Manufacturing | 1968 |
| R.Cooke Construction Services Ltd | Construction | 2017 |
| RAB Marketing Ltd | Administrative & support | 2025 |
| RAB Promotions Ltd | Wholesale & retail | 2024 |
| Rail Plant Haulage Ltd | Transport & logistics | 2024 |