| Midtercloud Ltd | Administrative & support | 2018 |
| Midweek Suppers Ltd | Hospitality | 2025 |
| Milawa Limited | Real estate | 2018 |
| Militake Ltd | Wholesale & retail | 2018 |
| Millcon Construction Ltd | Construction | 2020 |
| Millepelli Limited | Wholesale & retail | 1998 |
| Miller-Mead Group Ltd | Financial services | 2026 |
| Millington Associates Holdings Ltd | Manufacturing | 2020 |
| Mindexplore Assessments Ltd | Health & social care | 2025 |
| Mindful Financial Planning Limited | Financial services | 2020 |
| Mini Valley Kids Limited | Hospitality | 2024 |
| Minuets Limited | Arts & recreation | 2008 |
| Mirador Consultancy Limited | Administrative & support | 2013 |
| Mirai Built Limited | Professional & scientific | 2025 |
| Mirosa Global Ltd | Wholesale & retail | 2020 |
| MJ Logistics (UK) Ltd | Transport & logistics | 2014 |
| Mjgs Property Limited | Real estate | 2014 |
| MJR Communications Limited | Professional & scientific | 2015 |
| MJR Fitness Ltd | Arts & recreation | 2023 |
| MK Greenway Developments Limited | Construction | 2019 |
| Mlc-Co Ltd | Extraterritorial | 1992 |
| MLS Education Limited | Education | 2022 |
| Mmpl Investments Limited | Financial services | 2022 |
| Moathouse Ltd | Administrative & support | 2025 |
| MOD Marketing Limited | Administrative & support | 2005 |
| Modex Design Consultancy Limited | Professional & scientific | 2012 |
| Modex Design Investments Limited | Administrative & support | 2019 |
| Modulus Welding Systems Limited | Wholesale & retail | 2018 |
| MOL Services Limited | Administrative & support | 2018 |
| Molloy Holdings Limited | Financial services | 2019 |
| Molloy Properties Limited | Construction | 2003 |
| Momentous Fine Art Ltd. | Wholesale & retail | 2020 |
| Monaco Asset Management Limited | Administrative & support | 2007 |
| Monkey Dumpling Holdings Ltd | Administrative & support | 2026 |
| Mono Civil Engineering Ltd | Construction | 2020 |
| Montana`S Ltd | Wholesale & retail | 2008 |
| Moontrack Limited | Construction | 2021 |
| Mophaisti Ltd | Professional & scientific | 2025 |
| Moran & Sons Developments Ltd | Real estate | 2026 |
| More Driving Limited | Administrative & support | 2011 |
| More Rugby Ltd | Education | 2026 |
| Morgan Shields Group Ltd | Construction | 2018 |
| Morgan UK Limited | Manufacturing | 2002 |
| MORLAC23 Limited | Financial services | 2025 |
| Mornquest Ltd | Hospitality | 2024 |
| Mortgage Sorted Limited | Financial services | 2021 |
| Morval Caravans Limited | Manufacturing | 2018 |
| Motedis.Co.Uk Limited | Administrative & support | 2013 |
| Mother Nature Childcare Ltd | Education | 2018 |
| Motor Modder Ltd | Wholesale & retail | 2025 |
| Motorclub Car Care Ltd | Administrative & support | 2025 |
| Motovario Limited | Wholesale & retail | 1990 |
| Motteram Limited | Professional & scientific | 2014 |
| Mountbatten-Gould Capital Partners Limited | Other services | 2023 |
| Mountross Property Limited | Real estate | 2022 |
| Move Culture Ltd | Professional & scientific | 2026 |
| MP2 Developments Limited | Real estate | 2025 |
| MP66 Developments Ltd | Real estate | 2025 |
| MPC Electrical Limited | Construction | 2003 |
| MPC Mortgage & Protection Ltd | Financial services | 2018 |
| MPP 117DRFH Ltd | Real estate | 2025 |
| MPP 117DRLH Ltd | Real estate | 2025 |
| MPP INV Ltd | Financial services | 2026 |
| MPP MKP Ltd | Real estate | 2025 |
| MPP Mkplh Ltd | Real estate | 2026 |
| MS Estate Management Limited | Construction | 2003 |
| MS Mowbray Estates Limited | Real estate | 2026 |
| MSS Maintenance Ltd | Construction | 2024 |
| Msuh Global Limited | Wholesale & retail | 2023 |
| MT & TM Pereira Limited | Health & social care | 2020 |
| MTD Property Ltd | Real estate | 2018 |
| MTL Productions Limited | Wholesale & retail | 2023 |
| Mundinus Surgical Services Limited | Health & social care | 2022 |
| MUR Holdings Ltd | Financial services | 2017 |
| MVP (Search and Selection) Limited | Administrative & support | 2011 |
| MWP Developments Limited | Real estate | 2026 |
| MWP Rental Properties Limited | Real estate | 2016 |
| My Epanoui Limited | Administrative & support | 2025 |
| My Event Concierge Limited | Other services | 2021 |
| My Everlasting Voice Limited | Information & communication | 2024 |
| Myco Falcon Limited | Wholesale & retail | 2013 |
| Mysteryfootball Ltd | Wholesale & retail | 2021 |
| Mysterypitstop Ltd | Wholesale & retail | 2024 |
| Mystic Isle Coaches Limited | Transport & logistics | 2016 |
| N & a Holdings Limited | Financial services | 2015 |
| N J Performance Ltd | Professional & scientific | 2013 |
| N&O Property Partners Ltd | Real estate | 2026 |
| NAD Coffee Culture Limited | Hospitality | 2026 |
| Nakhla Space Limited | Administrative & support | 2011 |
| Nala Tonya Rose Revell Ltd | Extraterritorial | 2025 |
| Nascent Growth Management Limited | Professional & scientific | 2023 |
| Nationwide Windows & Carpet Linings Ltd | Wholesale & retail | 2023 |
| Natural Nails Droitwich Limited | Other services | 2020 |
| Natures Fayre Limited | Wholesale & retail | 2018 |
| NC Electrical Services Limited | Construction | 2026 |
| NC Property Investment Holdings Ltd | Real estate | 2026 |
| Nccd Electrical Services Limited | Construction | 2019 |
| Ncjk Limited | Professional & scientific | 2025 |
| NEB 2018 Limited | Administrative & support | 2026 |
| Nebula Vape Limited | Wholesale & retail | 2015 |