| Montgomery Accountants Ltd | Professional & scientific | 2025 |
| Moonage Daydream Ltd | Real estate | 2019 |
| Morlas Underwriting Limited | Financial services | 2009 |
| Morley Holdings Limited | Professional & scientific | 2000 |
| Mortgage Options (Partnership Division) Limited | Financial services | 2010 |
| MOTO101 Limited | Arts & recreation | 2015 |
| Mowbeck Developments Limited | Construction | 2023 |
| Mowhan Ltd | Hospitality | 2022 |
| MPC Healthcare Group Ltd. | Health & social care | 2016 |
| Mpundu Twins Investments Ltd | Financial services | 2026 |
| MR G'S Ice Cream Limited | Hospitality | 2013 |
| MR Johnson's Petcare Limited | Extraterritorial | 2010 |
| MR. G'S Limited | Hospitality | 2016 |
| MRP Consultants Ltd | Administrative & support | 2017 |
| Msec Cyber Security Ltd | Information & communication | 2022 |
| Msem UK Ltd | Construction | 2018 |
| MSK Group Limited | Wholesale & retail | 2015 |
| Mtcj Ltd | Manufacturing | 2023 |
| Mtcjl Ltd | Manufacturing | 2026 |
| MTR Removals Ltd | Transport & logistics | 2022 |
| Muiresk LLP | | 2009 |
| Mulberry Barns Manco Limited | Households | 2026 |
| Mulhall Leisure Consultancy Limited | Professional & scientific | 2017 |
| MUM Made Meals Ltd | Hospitality | 2024 |
| Munch Social Limited | Hospitality | 2025 |
| Munnimore Limited | Administrative & support | 2014 |
| Murphy Resurfacing Limited | Construction | 2024 |
| Musson Holdings Ltd | Financial services | 2017 |
| Musson Joinery (Holdings) Limited | Professional & scientific | 2014 |
| Musson Joinery Limited | Construction | 2001 |
| Mwat Limited | Energy | 2016 |
| MWDE11 Limited | Energy | 2018 |
| MWDN22 Limited | Energy | 2022 |
| MWEC21 Limited | Energy | 2021 |
| MWKB21 Limited | Energy | 2021 |
| MWLB11 Limited | Energy | 2018 |
| MWME11 Limited | Energy | 2018 |
| MWND21 Limited | Energy | 2021 |
| MWWG11 Limited | Energy | 2018 |
| My Care Coordinator Ltd | Health & social care | 2024 |
| My House Cleaner Ltd | Administrative & support | 2020 |
| My Pet Foods Limited | Extraterritorial | 2009 |
| Mycloudspace Ltd | Hospitality | 2011 |
| Mypad Rentals Ltd | Real estate | 2023 |
| Myti Products Ltd | Wholesale & retail | 2020 |
| N & a Cleaning Co Ltd | Administrative & support | 2016 |
| N K M Property Limited | Real estate | 2020 |
| N S a Building Ltd | Construction | 2018 |
| N Salmon Limited | Construction | 2015 |
| N.R. Wild Limited | Professional & scientific | 2005 |
| Naila Kachra Investments Limited | Financial services | 2018 |
| Namaste Builders Ltd | Construction | 2022 |
| Namaste Dining Grantham Limited | Hospitality | 2022 |
| Nameco (NO. 1139) Limited | Financial services | 2014 |
| Nameco (NO. 1185) Limited | Financial services | 2014 |
| Nameco (NO. 1264) Limited | Financial services | 2015 |
| Nameco (NO. 1275) Limited | Financial services | 2015 |
| Nameco (NO. 1282) Limited | Financial services | 2015 |
| Nameco (NO. 508) Limited | Financial services | 2000 |
| Nameco (NO. 631) Limited | Financial services | 2024 |
| Nameco (NO. 814) Limited | Financial services | 2003 |
| Nameco (NO. 981) Limited | Financial services | 2009 |
| Nameco (NO. 994) Limited | Financial services | 2010 |
| Nameco (NO. 995) Limited | Financial services | 2010 |
| Nameco (NO.19) Limited | Financial services | 1997 |
| Nameco (NO.246) Limited | Financial services | 1998 |
| Nameco (NO.341) Limited | Financial services | 1999 |
| Nameco (NO.356) Limited | Financial services | 1999 |
| Nameco (NO.512) Limited | Financial services | 2000 |
| Nameco (NO.801) Limited | Financial services | 2003 |
| Nameco 42B Limited | Financial services | 2011 |
| Namedis Ltd | Financial services | 2026 |
| Nanak Medicals Limited | Health & social care | 2023 |
| Naran Ltd | Construction | 2018 |
| Nation Fresh Foods Ltd | Wholesale & retail | 2023 |
| Naturalcity Limited | Construction | 1987 |
| Natures Playground Limited | Manufacturing | 2026 |
| Natyasree Dance Academy Limited | Wholesale & retail | 2024 |
| Nav-Focus Solutions Limited | Information & communication | 2015 |
| NBJ Business Solutions Ltd | Professional & scientific | 2016 |
| NC4 Vertical Limited | Professional & scientific | 2025 |
| NCA Property & Developments Ltd | Real estate | 2024 |
| Neighbourhood Friends Ltd | Health & social care | 2025 |
| Neil Bellamy Electrical Ltd | Construction | 2013 |
| Neil Mason Associates Limited | Real estate | 2014 |
| Neil Perkins Limited | Construction | 2002 |
| Nellie Supports Ltd | Health & social care | 2019 |
| Nelsmab Ltd | Health & social care | 2014 |
| Nelson Referencing Ltd | Information & communication | 2009 |
| Nemmy Limited | Hospitality | 2022 |
| Nesd Group Ltd | Construction | 2023 |
| Nesli Supermarket Limited | Administrative & support | 2017 |
| Nesthaven Limited | Financial services | 2017 |
| Netaji Ltd | Information & communication | 2025 |
| Netherite Limited | Financial services | 2014 |
| Nethersure Limited | Financial services | 2012 |
| Nett Property Ltd | Real estate | 2025 |
| Network Auto Paint Ltd | Wholesale & retail | 2017 |
| Neuruppin Underwriting Limited | Financial services | 2011 |
| Nevik Professional Services Limited | Administrative & support | 2024 |