| Min's Autos Ltd | Wholesale & retail | 2009 |
| Minas Holdings Limited | Real estate | 2026 |
| Mind Health Consulting Ltd | Health & social care | 2021 |
| Mint New Homes Ltd | Real estate | 2015 |
| Minuteless Ltd | Information & communication | 2022 |
| Mira Web Ltd | Other services | 2018 |
| Mirabel Design Limited | Arts & recreation | 2005 |
| Miracle Aesthetics Ltd | Other services | 2025 |
| Miracle Communications Limited | Information & communication | 1983 |
| Mirinaz Limited | Wholesale & retail | 2012 |
| Mirkyan Limited | Hospitality | 2025 |
| Miron Decoration Ltd | Construction | 2025 |
| Miryas General Trading Limited | Hospitality | 2015 |
| Mirzan NS Ltd | Construction | 2026 |
| Mischu Acquisitions 1 Limited | Real estate | 2019 |
| Mischu Capital Ltd | Real estate | 2017 |
| Mishi Global Ltd | Wholesale & retail | 2026 |
| Miss Mandana Limited | Health & social care | 2015 |
| Miss Pokeno Limited | Arts & recreation | 2013 |
| Mistry HR Insights Consulting Ltd | Professional & scientific | 2024 |
| Misuma Limited | Construction | 1994 |
| Mitchell Precision Engineering Limited | Manufacturing | 2012 |
| Mitsu Masrani MED Limited | Health & social care | 2023 |
| MJ Platform Ltd | Information & communication | 2023 |
| Mj&Co Property Ltd | Professional & scientific | 2021 |
| MJB Sports Therapy Limited | Other services | 2021 |
| MJJ Plumbing & Heating Limited | Construction | 2017 |
| MJN Consulting Services LLP | | 2007 |
| MJR Enterprises Ltd | Administrative & support | 2013 |
| MK BIM Solutions Limited | Professional & scientific | 2014 |
| MK Carpentry Services Limited | Construction | 2015 |
| MK Construction Group Limited | Construction | 2019 |
| MK Driving School Ltd | Education | 2018 |
| MK Electric Services Ltd | Construction | 2024 |
| MK Fresh Dish Limited | Wholesale & retail | 2025 |
| MK Gasworks Ltd | Construction | 2024 |
| MK Properties and Construction Limited | Real estate | 2015 |
| MK Water Power & GAS Limited | Construction | 2017 |
| Mkkd Property Ltd | Real estate | 2024 |
| Mmant Ltd | Construction | 2023 |
| MMH Medical Ltd | Health & social care | 2013 |
| MMJ Enterprise Limited | Wholesale & retail | 2024 |
| MML Solutions UK Limited | Professional & scientific | 2009 |
| MNP Enterprise Ltd | Education | 2023 |
| Mnsa Limited | Professional & scientific | 2019 |
| MO Beauty Supply Limited | Wholesale & retail | 2025 |
| Moatgrove Limited | Financial services | 1987 |
| Mobile Home Sales & Lettings Ltd | Real estate | 2017 |
| Mobile Home Sales & Management Ltd | Other services | 2013 |
| Mobile Home Sales and Lettings Agents Limited | Real estate | 2020 |
| Mode Property Developments Limited | Construction | 2004 |
| Mode Property Holdings Limited | Financial services | 2011 |
| Modecor UK Limited | Manufacturing | 2025 |
| Modern Engineers Limited | Wholesale & retail | 1993 |
| Modern Haly Designs Limited | Professional & scientific | 2025 |
| Modi Properties Private Limited | Real estate | 2022 |
| Modular Accommodation Systems Limited | Professional & scientific | 2007 |
| MOE Kyun Ltd | Wholesale & retail | 2020 |
| MOE Town Limited | Administrative & support | 2017 |
| Moerans Limited | Professional & scientific | 2015 |
| Moerans Solicitors LLP | | 2023 |
| MOH P C Limited | Construction | 2011 |
| Mohan and Sons Ltd | Real estate | 2026 |
| Mohan Singh Properties Limited | Real estate | 2003 |
| MOI + ME Ltd | Wholesale & retail | 2021 |
| Moksha Investments Limited | Real estate | 2016 |
| Molatin Limited | Professional & scientific | 2012 |
| Mold Interiors UK Ltd | Construction | 2026 |
| Momentum Parts Ltd | Wholesale & retail | 2022 |
| MON Desir Limited | Hospitality | 2003 |
| Mona Fine Jewellery Ltd | Wholesale & retail | 2019 |
| Monaksh Private Limited | Wholesale & retail | 2020 |
| Monarchs House Limited | Real estate | 2014 |
| Money Base Ltd | Wholesale & retail | 2019 |
| Moneyfy Investors Ltd | Real estate | 2021 |
| Moneyhill Property Limited | Real estate | 2025 |
| Moniri Properties Ltd | Real estate | 2021 |
| Monittwall Ltd | Wholesale & retail | 2022 |
| Montage Timepiece Ltd | Wholesale & retail | 2026 |
| Montgomery Building RTM Company Limited | Households | 2024 |
| Montpelier Property Management Ltd | Real estate | 2026 |
| Monty Joshi Investments Limited | Real estate | 2021 |
| Monumental Assets Limited | Real estate | 2022 |
| MOO Jevons Catering Limited | Hospitality | 2019 |
| Moofushi Holdings Ltd | Financial services | 2025 |
| Moonstar Solutions Limited | Wholesale & retail | 2016 |
| Moore Build Limited | Construction | 2017 |
| MOORGATEC2 Limited | Professional & scientific | 2013 |
| Mopodo Ltd | Wholesale & retail | 2004 |
| Morello International Limited | Administrative & support | 1997 |
| Morenike Ltd | Administrative & support | 2016 |
| Morenvelopes Ltd | Manufacturing | 2007 |
| Morfruit Limited | Administrative & support | 1981 |
| Morgan & Morgan Property Investors Limited | Real estate | 2017 |
| Morgan Aesthetics Limited | Health & social care | 2016 |
| Mori Trading Limited | Wholesale & retail | 2026 |
| Morpheus Accountants Limited | Professional & scientific | 2016 |
| Mortal Coils Limited | Information & communication | 2023 |
| Mortgage Vision Ltd | Financial services | 2020 |
| Morton Countrywide Group Limited | Real estate | 2025 |