| MTG Moto Ltd | Professional & scientific | 2016 |
| Mthdent Ltd | Health & social care | 2025 |
| Mthokocourier Limited | Transport & logistics | 2026 |
| MTJ Bookeeping Ltd | Professional & scientific | 2022 |
| MTL Plastering and Construction Ltd | Construction | 2016 |
| MTM Factory Ltd | Information & communication | 2016 |
| Mtshuma Ltd | Transport & logistics | 2025 |
| MUA Trading Ltd | Wholesale & retail | 2025 |
| Mubashar Nazar Ltd | Wholesale & retail | 2026 |
| Mulberry Homelets Ltd | Real estate | 2014 |
| Mulberry Homes UAE Limited | Real estate | 2024 |
| Mulberry Manor Care Limited | Health & social care | 2022 |
| Mullani Retail Limited | Wholesale & retail | 2020 |
| Multicity Properties Ltd | Real estate | 2015 |
| Multiple Sclerosis Therapy Centre (South Yorkshire) Ltd | Health & social care | 1988 |
| Multiply Logistics North Holdings Limited | Real estate | 2017 |
| Multiply Logistics North LP | | 2017 |
| Multitask Personnel Limited | Administrative & support | 2010 |
| Multitech Maintenance Services Ltd. | Administrative & support | 2001 |
| Mumford International Limited | Professional & scientific | 2023 |
| Munch by MEL Ltd | Hospitality | 2026 |
| Munero Limited | Information & communication | 2024 |
| Muriel Design Ltd. | Arts & recreation | 2016 |
| Murphy's Bowl Ltd | Wholesale & retail | 2024 |
| Musa Sports Ltd | Wholesale & retail | 2022 |
| Muscle Blend Ltd | Information & communication | 2016 |
| Muscle Madness Bodybuilding and Fitness Gym Ltd | Arts & recreation | 2023 |
| Muscle Makers Gym Limited | Arts & recreation | 2017 |
| Museum CA2 7QJ Ltd | Hospitality | 2019 |
| Music Factory Holdings Limited | Financial services | 2023 |
| Music Factory Music Limited | Information & communication | 2024 |
| Music Factory Recordings Limited | Information & communication | 2023 |
| Musicscape Limited | Information & communication | 2022 |
| Muslim Burial Alliance CIC | Other services | 2026 |
| Must Know Before YOU Go Limited | Information & communication | 2013 |
| MUV Media Ltd | Information & communication | 2023 |
| Muwonge Units Limited | Manufacturing | 2025 |
| Muzzys Autoz Ltd | Wholesale & retail | 2023 |
| MWA Management Consultancy Ltd | Professional & scientific | 2025 |
| Mway Communications Limited | Information & communication | 2001 |
| Mway Services Limited | Construction | 2010 |
| My Foods UK Limited | Manufacturing | 2009 |
| My Foods Worldwide Limited | Wholesale & retail | 2009 |
| My Fusion Energy LP | | 2013 |
| My Fusion Heating LP | | 2008 |
| My Geegee Limited | Wholesale & retail | 2013 |
| My Home UK Properties Limited | Real estate | 2025 |
| My Network for Women | Other services | 2018 |
| My Planet Energy Ltd | Wholesale & retail | 2020 |
| My Property Solutions Group Limited | Real estate | 2022 |
| My Scaffolding Limited | Construction | 2023 |
| My Yorkshire Pubs Limited | Hospitality | 2022 |
| Myautobot Ltd | Information & communication | 2025 |
| Myco Construction Limited | Construction | 2013 |
| Mydetherapy Limited | Health & social care | 2025 |
| MYK Aspen Limited | Professional & scientific | 2018 |
| MYK Bismarck Limited | Professional & scientific | 2019 |
| MYK Care Ltd | Professional & scientific | 2017 |
| MYK Coral Limited | Professional & scientific | 2019 |
| MYK Elder Limited | Professional & scientific | 2022 |
| Mystic Cleaning Services Limited | Administrative & support | 2025 |
| Mystic Realms Trading Ltd | Wholesale & retail | 2023 |
| N & JAY Ltd | Hospitality | 2022 |
| N & S Kirk Limited | Hospitality | 2016 |
| N Crookes Ltd | Construction | 2020 |
| N DEE Joinery Limited | Construction | 2025 |
| N J C Interiors Limited | Construction | 2025 |
| N Oxby Limited | Other services | 2003 |
| N Scotties Limited | Wholesale & retail | 2020 |
| N Webster Limited | Health & social care | 2011 |
| N Y Fisheries Ltd | Wholesale & retail | 2024 |
| N&B78 Limited | Health & social care | 2026 |
| N&M Brothers Limited | Wholesale & retail | 2025 |
| N-Ark Haulage Ltd | Transport & logistics | 2022 |
| N. Hagan Limited | Manufacturing | 2001 |
| N.A.W. Group Ltd | Construction | 2018 |
| N.U Logistics Ltd | Other services | 2025 |
| N.Y Commodities Ltd | Wholesale & retail | 2013 |
| Nabia Services Ltd | Hospitality | 2018 |
| Nabiha Hassaan Medical Ltd | Health & social care | 2026 |
| Nabrum Ltd | Administrative & support | 2015 |
| Nadeem Boxing Ltd | Arts & recreation | 2025 |
| Nadeem Poultry Ltd | Wholesale & retail | 2025 |
| Nadeem Real Estates Ltd | Real estate | 2024 |
| Nadlan Rein Limited | Other services | 2017 |
| NAFISA22 Ltd | Health & social care | 2022 |
| Nagolu Limited | Wholesale & retail | 2025 |
| Nags Head (Clowne) Ltd | Hospitality | 2025 |
| Nagyal Limited | Health & social care | 2013 |
| Najam Group Ltd | Wholesale & retail | 2020 |
| Naked Brands Limited | Wholesale & retail | 2006 |
| Nakodar Trading Limited | Wholesale & retail | 2024 |
| Nano Print Ltd | Manufacturing | 2019 |
| Nanocode Ltd | Information & communication | 2014 |
| Napper Network Ltd | Information & communication | 2021 |
| Naracci Holdings Limited | Wholesale & retail | 2022 |
| Naratek Ltd | Information & communication | 2025 |
| Narma Hire Limited | Administrative & support | 2026 |
| Narrow Escape Holdings Ltd | Real estate | 2026 |
| Narrow Margins Holdings Ltd | Financial services | 2025 |