| Multiplier Distributions Limited | Wholesale & retail | 2022 |
| Multiqo Ltd | Financial services | 2019 |
| Mumbles Specsavers Limited | Wholesale & retail | 2023 |
| Murraynet Limited | Information & communication | 2019 |
| Music Matters Bypittbull Ltd | Information & communication | 2007 |
| Musselburgh Specsavers Limited | Wholesale & retail | 2006 |
| Musselburgh Visionplus Limited | Wholesale & retail | 2006 |
| Muswell Hill Specsavers Limited | Wholesale & retail | 2008 |
| Muswell Hill Visionplus Limited | Wholesale & retail | 2008 |
| Muttkuts (Portchester) Ltd | Wholesale & retail | 2022 |
| Muttkuts Ltd | Wholesale & retail | 2020 |
| MVB Health Limited | Health & social care | 2014 |
| MVF Management Limited | Real estate | 2025 |
| MW French & Co Limited | Real estate | 2022 |
| MWA Finance NO1 Ltd | Financial services | 2023 |
| MWA Financial Nominees Ltd | Extraterritorial | 2023 |
| MWA Holdings Limited | Administrative & support | 2017 |
| MWA Investment Management Limited | Financial services | 2020 |
| MWA Mortgages Ltd | Financial services | 2019 |
| MXF Design Limited | Professional & scientific | 2025 |
| My BOY CAN Community Interest Company | Education | 2020 |
| My Choice Mortgage Ltd | Financial services | 2020 |
| My Devco Limited | Financial services | 2023 |
| My Education (UK) Limited | Administrative & support | 2013 |
| My Holidays On-Line (UK) Limited | Administrative & support | 2011 |
| My Inner Space Limited | Arts & recreation | 2017 |
| My Learning Cloud Limited | Wholesale & retail | 2012 |
| My Photo Gifts Limited | Manufacturing | 2019 |
| My REC Space Ltd | Professional & scientific | 2019 |
| My Sales Agent Limited | Administrative & support | 2026 |
| My Tesla Travel Ltd | Transport & logistics | 2019 |
| My UK Properties Limited | Real estate | 2024 |
| My View Limited | Professional & scientific | 2019 |
| Mycompany Ltd | Professional & scientific | 2024 |
| Mylearningworx Limited | Information & communication | 2012 |
| Mymemorycard Ltd | Wholesale & retail | 2022 |
| Mypickerpal Limited | Manufacturing | 2025 |
| MYS Marine Limited | Transport & logistics | 2014 |
| Myscore Limited | Information & communication | 2007 |
| Mystery Tavern Ltd | Wholesale & retail | 2024 |
| Mystery Tavern PUB Co Ltd | Wholesale & retail | 2025 |
| Mytharis Studios Limited | Information & communication | 2023 |
| Mywindowscleaner.Com Ltd | Administrative & support | 2023 |
| MZ Jaffer Ltd | Real estate | 2025 |
| MÔR Salt Ltd | Manufacturing | 2026 |
| N a Investment Management Ltd | Professional & scientific | 2012 |
| N C Contractors and Sons Limited | Construction | 2023 |
| N J Kearney Electrical Limited | Construction | 2022 |
| N Lutas Ltd | Real estate | 2024 |
| N W Stubbington Limited | Construction | 2015 |
| N.T.P.E. Limited | Wholesale & retail | 2014 |
| N17 Electrical Solutions Limited | Construction | 2024 |
| N2C Ltd | Professional & scientific | 2025 |
| N3XUS Consulting Ltd | Real estate | 2024 |
| Naafi Incorporated Trustees | Financial services | 1979 |
| Naafi Pension Fund Trustees | Financial services | 1979 |
| Naafi UK Limited | Wholesale & retail | 2017 |
| Nabais Cardio Expert Consulting Ltd | Health & social care | 2025 |
| Naga Viper Pepper Limited | Hospitality | 2015 |
| Nahid Spice Limited | Hospitality | 2022 |
| Nails by Kelley Ltd | Other services | 2024 |
| Nailsea Specsavers Limited | Wholesale & retail | 2002 |
| Najmw Ltd | Construction | 2026 |
| NAK Design Ltd | Professional & scientific | 2024 |
| Nano VET Limited | Manufacturing | 2011 |
| Nanoo Wear Ltd | Wholesale & retail | 2026 |
| Nantwich Visionplus Limited | Wholesale & retail | 2003 |
| Nanuk Store Ltd | Wholesale & retail | 2016 |
| NAP Medical Ltd | Health & social care | 2023 |
| NAP Property Services Ltd | Real estate | 2022 |
| Naphill and Walter's ASH Gazette Limited | Other services | 2025 |
| Nash Electrical Limited | Construction | 2005 |
| Natal Bean at Hopscotch CIC | Hospitality | 2026 |
| Natal Bean Limited | Hospitality | 2026 |
| Natalie Lamprell Consulting Ltd | Professional & scientific | 2026 |
| Nathan Martin Photography Ltd | Professional & scientific | 2025 |
| Nathu Convenience Limited | Wholesale & retail | 2023 |
| National Air Traffic Services Limited | Transport & logistics | 2006 |
| National Contracting Solutions Ltd | Professional & scientific | 2024 |
| National Skills Group Ltd | Administrative & support | 2017 |
| Nationonline Ltd | Information & communication | 2023 |
| Nationwide Hire Ltd | Administrative & support | 1995 |
| Nats (EN Route) Public Limited Company | Transport & logistics | 2000 |
| Nats (Services) Limited | Transport & logistics | 2000 |
| Nats Employee Sharetrust Limited | Transport & logistics | 2001 |
| Nats Holdings Limited | Transport & logistics | 2001 |
| Nats Limited | Transport & logistics | 1996 |
| Nats Solutions Limited | Transport & logistics | 2014 |
| Natsnav Limited | Transport & logistics | 2001 |
| Natura Muse Ltd | Manufacturing | 2025 |
| Naturally Paws Limited | Wholesale & retail | 2017 |
| Naturesong Trading Ltd | Wholesale & retail | 2025 |
| Nature`S Touch Limited | Administrative & support | 2008 |
| Nautical Property Services Ltd | Households | 2024 |
| Nautilus Dynamics UK Ltd | Professional & scientific | 2024 |
| Nava Group Ltd | Financial services | 2026 |
| Navex International Limited | Transport & logistics | 2018 |
| Navigate HR Limited | Administrative & support | 2019 |
| Navigator Group Ltd | Financial services | 2022 |
| Navii Media Ltd | Wholesale & retail | 2021 |