| MHM Constructions Ltd | Construction | 2021 |
| MI Dental Care Limited | Health & social care | 2015 |
| MIA Sabrina Transport Limited | Transport & logistics | 2021 |
| Mian Noraiz Limited | Wholesale & retail | 2025 |
| Micabr Properties Ltd | Real estate | 2026 |
| Michael NEL and Associates Limited | Health & social care | 2014 |
| Michael Wallace Holdings Ltd | Real estate | 2024 |
| Michelins Britannia Limited | Real estate | 2020 |
| Michelins Estates Limited | Real estate | 2022 |
| Michelins Farm Limited | Real estate | 2023 |
| Michelins Malt House Limited | Real estate | 2019 |
| Michelins Penton Limited | Real estate | 2019 |
| Michelins Properties Limited | Financial services | 2013 |
| Michelins Renovations Limited | Real estate | 2023 |
| Michelins Residential Limited | Real estate | 2019 |
| Michelins ST Marys Limited | Real estate | 2021 |
| Michelins Trading Limited | Administrative & support | 2020 |
| Michst Limited | Construction | 2014 |
| Mici Limited | Construction | 2023 |
| Mick's Mechanical Services Limited | Wholesale & retail | 2021 |
| Microsurf Limited | Professional & scientific | 1999 |
| Midas Building Services Limited | Construction | 2023 |
| Midas Mercatura Limited | Wholesale & retail | 2026 |
| Midasse Resource Ltd | Professional & scientific | 2014 |
| Midlands Schools Cricket Ltd | Arts & recreation | 2024 |
| Midpoint Solutions Ltd | Construction | 2023 |
| Miheconsultancy Ltd | Information & communication | 2025 |
| Mike Hutchings Ltd | Health & social care | 2023 |
| Mikko Limited | Information & communication | 2015 |
| Milamoo Consulting Limited | Professional & scientific | 2021 |
| Miles of Mastic Ltd | Construction | 2004 |
| Milkris Interiors Limited | Construction | 2016 |
| Miller DRY TEC Ltd | Administrative & support | 2010 |
| Millers Events LLP | | 2018 |
| Milli's Ltd | Wholesale & retail | 2021 |
| Milligan Street Limited | Other services | 2026 |
| Milligan Street Trading Limited | Other services | 2000 |
| Mills Logistics Ltd | Manufacturing | 2022 |
| Milsi Ltd | Real estate | 2025 |
| Mimilake Limited | Hospitality | 2022 |
| Mimiq Investment Portfolio Limited | Real estate | 2002 |
| Mindee Ltd | Transport & logistics | 2019 |
| Minute Mirror Ltd | Information & communication | 2024 |
| Minxies Boutique Ltd | Wholesale & retail | 2013 |
| Minxy Limited | Other services | 2015 |
| MIO Yatai London Ltd | Hospitality | 2025 |
| Miracool Ltd | Administrative & support | 2009 |
| Miran Holdings Ltd | Households | 2022 |
| Miranda Business Consultancy Ltd | Professional & scientific | 2026 |
| Mirari Technology Limited | Wholesale & retail | 2025 |
| Miras Projects Limited | Other services | 2016 |
| Miras Tax Ltd | Professional & scientific | 2024 |
| Miriana Trans Limited | Transport & logistics | 2019 |
| Mishri Associates Ltd | Transport & logistics | 2022 |
| Mishri Traders Ltd | Wholesale & retail | 2026 |
| Misl Properties Limited | Real estate | 2022 |
| MITIG8 Testing Services Limited | Information & communication | 2000 |
| Mitru Developments Ltd | Construction | 2021 |
| MIX 'N LAY Concrete Supplies Limited | Construction | 1981 |
| Miza Ltd | Administrative & support | 2022 |
| MJ Civils & Construction Ltd | Construction | 2023 |
| MJ Construction (South East) Limited | Construction | 2022 |
| MJ Heroine Ltd | Wholesale & retail | 2023 |
| MJ Surveying Services Ltd | Professional & scientific | 2024 |
| MJB Developments and Restorations Ltd | Construction | 2022 |
| MJJ Crossways Limited | Construction | 2013 |
| MJP Financial Services Limited | Professional & scientific | 2015 |
| MJS Air Conditioning Ltd | Construction | 2018 |
| MJV Solutions Ltd | Construction | 2025 |
| MK Kapila Ltd | Real estate | 2023 |
| MK Pepper Limited | Professional & scientific | 2024 |
| MK Protection Services Ltd | Administrative & support | 2022 |
| MKC Consulting Ltd | Professional & scientific | 2024 |
| MKD Investments Ltd | Real estate | 2020 |
| MKR Consultants Ltd | Real estate | 2015 |
| MKR Financial Services Ltd | Professional & scientific | 2014 |
| Mlcarpentery Limited | Construction | 2024 |
| Mlegal Support Ltd | Professional & scientific | 2024 |
| MLJ Property Construction & Investment Limited | Construction | 2026 |
| MLK Incorporated Limited | Administrative & support | 2018 |
| MLR Chowdhury Ltd | Wholesale & retail | 2014 |
| MM Carpentry Limited | Manufacturing | 2018 |
| Mmartin Properties Ltd | Real estate | 2026 |
| Mmgm Construction Limited | Construction | 2026 |
| MMH Electrics Ltd | Other services | 2021 |
| MMT Holdings Limited | Financial services | 2025 |
| Mnandi Limited | Health & social care | 2007 |
| MNE Windows & Door Installations Ltd | Construction | 2013 |
| Mngs Builders Ltd | Construction | 2026 |
| MNL Properties Ltd | Real estate | 2019 |
| MNS Limited | Wholesale & retail | 2000 |
| MNS Property Management Limited | Construction | 2025 |
| Mobile Planet UK Limited | Financial services | 2006 |
| Mobile Vape Local Limited | Wholesale & retail | 2026 |
| Mobilise My IT Limited | Information & communication | 2012 |
| MOD Box Interiors Ltd | Wholesale & retail | 2025 |
| Modefast Ltd | Construction | 2020 |
| Modern Logic Limited | Professional & scientific | 2005 |
| Modern Optics Ltd | Health & social care | 2015 |
| Moderno Build Limited | Construction | 2025 |