| Mind Spark Education Limited | Professional & scientific | 2023 |
| Mindfit Clinics Ltd | Health & social care | 2021 |
| Mindsalike Mgmt Ltd | Professional & scientific | 2023 |
| Mindset Business Psychology Services Limited | Education | 2018 |
| Mine Monies Ltd | Construction | 2019 |
| Mineral Point Music Ltd. | Information & communication | 2016 |
| Minmar Property Estates Ltd | Real estate | 2025 |
| Mint Stripe Limited | Construction | 2014 |
| Mirage Technologies Limited | Information & communication | 1997 |
| Mirem Construction Ltd | Construction | 2019 |
| Miroy Estates Limited | Real estate | 2026 |
| Mirza Capital Investments Limited | Information & communication | 2019 |
| Miss Latte Ltd | Hospitality | 2024 |
| Mistik Takeaway Ltd | Hospitality | 2024 |
| Mitch Murray Music Limited | Information & communication | 2021 |
| Mitchwick Commercial Limited | Real estate | 2003 |
| Mitchwick Limited | Real estate | 2003 |
| Mitfire Ltd | Construction | 2024 |
| Mitre Interiors Ltd | Construction | 2020 |
| Mitu Mechanical Ltd | Construction | 2018 |
| Mitzu Care Limited | Health & social care | 2024 |
| MJ Capital Ltd | Information & communication | 1997 |
| MJ Kingsley Psychology Ltd | Health & social care | 2023 |
| MJ Saunders HR Ltd | Administrative & support | 2025 |
| MJB Entertainment Group Ltd | Other services | 2020 |
| MJC Installations Limited | Construction | 2016 |
| MJD Cleaning Services Limited | Administrative & support | 2002 |
| Mjmengineering Ltd | Construction | 2019 |
| MJT Consultants Ltd | Professional & scientific | 2009 |
| MJX Healthcare Limited | Public administration | 2023 |
| MK Engineer Links Ltd. | Real estate | 2014 |
| MK Optics Limited | Health & social care | 2019 |
| MK Property Investor Ltd | Real estate | 2023 |
| MK58 Ltd | Hospitality | 2023 |
| MKP Properties Limited | Real estate | 2016 |
| ML Project Management Services Ltd | Financial services | 2018 |
| MLG Holdings Limited | Hospitality | 2012 |
| MLG London Ltd | Real estate | 2024 |
| Mlgcc Ltd | Construction | 2019 |
| MLJ 77 Construction Ltd | Construction | 2018 |
| MM Hair Studio Ltd | Other services | 2018 |
| MM Project Ltd | Construction | 2018 |
| MM Telecoms Ltd | Information & communication | 2018 |
| Mmgw Limited | Professional & scientific | 2013 |
| MMH Interiors Ltd | Construction | 2026 |
| Mmtae Ltd | Construction | 2023 |
| MN Developers Ltd | Construction | 2025 |
| Mnav Ltd | Information & communication | 2025 |
| MNS 99 Ltd | Wholesale & retail | 2022 |
| MNS 99 Properties Ltd | Real estate | 2022 |
| MO Import Export & Distribution Limited | Wholesale & retail | 2016 |
| Mobile Bar Events Ltd | Administrative & support | 2025 |
| Mobytech Projects Limited | Information & communication | 2017 |
| Moda Minx Limited | Wholesale & retail | 2015 |
| Modern Movers Limited | Transport & logistics | 2021 |
| Modius Solutions Limited | Information & communication | 2010 |
| Mody Property Company Ltd | Real estate | 2002 |
| Modys Ltd | Real estate | 2009 |
| Mohabir Ltd | Hospitality | 2018 |
| Mohamed Seif Limited | Professional & scientific | 2011 |
| Mokrynski International (UK) Limited | Professional & scientific | 2008 |
| Molot Ltd | Construction | 2022 |
| Momo Collective Limited | Real estate | 2026 |
| Monarchy Properties Limited | Real estate | 2021 |
| MONIK76 Ltd | Construction | 2020 |
| Monkhams Investments Limited | Real estate | 2015 |
| Mono Chrono Ltd | Wholesale & retail | 2026 |
| Montague Associates Limited | Real estate | 2012 |
| Montauk Limited | Professional & scientific | 2019 |
| Monteron Limited | Professional & scientific | 2026 |
| Montrose Capital Solutions Limited | Financial services | 2025 |
| Monument Two Limited | Administrative & support | 2016 |
| Monzil ( UK ) Limited | Wholesale & retail | 2016 |
| Moonfix Limited | Construction | 2006 |
| Moonlight Design Limited | Construction | 2003 |
| Moonreef Limited | Construction | 2006 |
| Moore Advisory Ltd | Professional & scientific | 2016 |
| Morada Developments Limited | Real estate | 1999 |
| Morgan Investment Properties Ltd | Real estate | 2024 |
| Morgan Sharp Contractors Limited | Administrative & support | 2016 |
| Morrell and Bert Ltd | Construction | 2016 |
| Mosaic Kitchen Ltd | Hospitality | 2017 |
| Moss Sustainable Supplies Ltd | Manufacturing | 2024 |
| Mota Bhai Services Limited | Wholesale & retail | 2026 |
| Mothers Ltd | Real estate | 2005 |
| Mothers Peace Limited | Health & social care | 2016 |
| Motion Production Ltd | Other services | 2018 |
| Motor Master Services Limited | Wholesale & retail | 2024 |
| Motor Masters Ilford Services Limited | Wholesale & retail | 2016 |
| Moviegoer Productions Ltd | Information & communication | 2018 |
| Movmo Ltd | Information & communication | 2023 |
| MPB Property Management Limited | Other services | 2019 |
| Mpcb Travel Limited | Transport & logistics | 2004 |
| MPK & Luck Construction Ltd | Other services | 2016 |
| Mpkk Ltd | Construction | 2015 |
| MPS Controls Limited | Information & communication | 2001 |
| MPS Services (Warks) Ltd | Wholesale & retail | 2024 |
| MR and MRS Cooper Limited | Real estate | 2013 |
| MR Art Gallery Ltd | Administrative & support | 2017 |
| MR Chans Food Ltd | Hospitality | 2024 |