| MGS Plumbing & Heating Solutions Limited | Construction | 2021 |
| MGZ London Ltd | Wholesale & retail | 2025 |
| MH & Associates Ltd | Professional & scientific | 2021 |
| MH Elite Properties Limited | Construction | 2025 |
| MH Handyman Services Ltd | Construction | 2026 |
| MH Restoration Limited | Construction | 2017 |
| MHA Advisory Ltd | Financial services | 2025 |
| MHA Audit Holdings Ltd | Financial services | 2025 |
| MHA Audit LLP | | 2011 |
| MHA Audit Services LLP | | 2025 |
| MHA Caves Investment Management Limited | Financial services | 2011 |
| MHA Corporate Finance Limited | Professional & scientific | 2001 |
| MHA Financial Solutions Limited | Financial services | 2014 |
| MHA Global Property Ltd | Real estate | 2021 |
| MHA IT Solutions Ltd | Information & communication | 2023 |
| MHA Macintyre Hudson Consulting Limited | Administrative & support | 2019 |
| MHA Member LLP | | 2025 |
| MHA PLC | Financial services | 2025 |
| MHA Service Limited | Other services | 2010 |
| MHA Tax Safe Limited | Administrative & support | 2020 |
| MHA Trustees Corporation Limited | Administrative & support | 2023 |
| MHA Wealth Limited | Financial services | 1985 |
| MHA Wealth Management Holdings Limited | Financial services | 2021 |
| MHA World Trading Ltd | Wholesale & retail | 2026 |
| Mhare Business Systems Limited | Information & communication | 2012 |
| Mhca Limited | Professional & scientific | 2010 |
| MHK Groups of Companies Ltd | Wholesale & retail | 2025 |
| MHL Catering Limited | Hospitality | 2016 |
| MHM Health Providers Limited | Health & social care | 2011 |
| MHM Travels Ltd | Administrative & support | 2026 |
| MHV Smile Centre Limited | Health & social care | 2014 |
| MI Remaps Ltd | Wholesale & retail | 2026 |
| MI Storage Ltd | Transport & logistics | 2020 |
| MIA Harlow Photography Ltd | Professional & scientific | 2009 |
| MIA Lion Estates Ltd | Real estate | 2025 |
| MIA Nails MK2 Ltd | Other services | 2022 |
| MIA TUI Ltd | Manufacturing | 2010 |
| MIA Wealth Limited | Financial services | 2024 |
| MIB Management Services Limited | Professional & scientific | 2009 |
| MIB Portal Services Limited | Administrative & support | 2010 |
| Mibiz Ltd | Transport & logistics | 2016 |
| Mibtek Solutions Limited | Wholesale & retail | 2012 |
| Mica Engineering Ltd | Manufacturing | 2017 |
| Mica Paris Live Limited | Arts & recreation | 2022 |
| Mica Paris Management Limited | Arts & recreation | 2022 |
| Micah & Jesse Secretaries Limited | Real estate | 2020 |
| Micahjudah Co. Ltd | Real estate | 2024 |
| Micdav Ltd | Real estate | 2021 |
| Michael Boast Engineering Consultancy Limited | Administrative & support | 2001 |
| Michael Boast Property Services Limited | Real estate | 2015 |
| Michael D Ibbeson Limited | Construction | 2012 |
| Michael Graham Estate Agents (Aylesbury) Limited | Real estate | 2010 |
| Michael Graham Estate Agents (Bedford) Limited | Real estate | 2009 |
| Michael Graham Estate Agents (Buckingham) Limited | Real estate | 2006 |
| Michael Graham Estate Agents (Commercial) Limited | Extraterritorial | 2012 |
| Michael Graham Estate Agents (Hitchin) Limited | Real estate | 2014 |
| Michael Graham Estate Agents (Kensington & Chelsea) Limited | Real estate | 2021 |
| Michael Graham Estate Agents (Milton Keynes) Limited | Real estate | 2002 |
| Michael Graham Estate Agents (Newport Pagnell) Limited | Real estate | 1999 |
| Michael Graham Estate Agents (Northampton) Ltd | Real estate | 2007 |
| Michael Graham Estate Agents (Princes Risborough) Limited | Real estate | 2013 |
| Michael Graham Estate Agents (Stony Stratford) Limited | Real estate | 2000 |
| Michael Graham Estate Agents (Towcester) Limited | Real estate | 2005 |
| Michael Graham Estate Agents (Woburn Sands) Limited | Real estate | 2011 |
| Michael Graham Estate Agents Limited | Real estate | 1998 |
| Michael Graham Financial Services Limited | Financial services | 2002 |
| Michael Graham Surveyors Limited | Real estate | 1999 |
| Michael Green Coaching Ltd | Education | 2023 |
| Michael Hardiman Investments LLP | | 2010 |
| Michael Henry MD Ltd | Health & social care | 2025 |
| Michael Hornsby & Co Limited | Professional & scientific | 2007 |
| Michael Law Solicitors Limited | Professional & scientific | 2020 |
| Michael MK Ltd | Transport & logistics | 2019 |
| Michael OZZ Limited | Wholesale & retail | 2017 |
| Michael Salisbury Ltd | Construction | 2021 |
| Michael Sharma Group Ltd | Administrative & support | 2017 |
| Michael V.S. Hardiman & Associates Limited | Professional & scientific | 1999 |
| Michaela Tait & Associates Limited | Professional & scientific | 2011 |
| Michaelangelo Productions Ltd | Information & communication | 2011 |
| Michalia UK Limited | Construction | 2022 |
| Michees Ltd | Information & communication | 2015 |
| Mick Global Limited | Information & communication | 2019 |
| Mick Wood Heating Services Limited | Construction | 2004 |
| Miclearance Ltd | Construction | 2024 |
| Micro Dash Properties Limited | Real estate | 2001 |
| Micro Drones Limited | Wholesale & retail | 2025 |
| Micro Minis Limited | Education | 2025 |
| Micro Solutions Ltd | Information & communication | 2023 |
| Microbiological Engineering Limited | Professional & scientific | 2009 |
| Microdoser Ltd | Manufacturing | 2019 |
| Micromacs Computers Ltd | Information & communication | 2016 |
| Microsmiths Limited | Wholesale & retail | 1985 |
| MID Bedfordshire Investments Limited | Real estate | 2008 |
| MID Bucks Performing Arts Festival Ltd | Arts & recreation | 2024 |
| Midas Alliance Limited | Administrative & support | 2016 |
| Midas Property Services (MK) Limited | Construction | 2004 |
| Midas Property Services (Residential) Limited | Construction | 1996 |
| Midastouch Solutions Mitsubishi Services Limited | Administrative & support | 2016 |
| Midd Properties Ltd | Real estate | 2025 |
| Middle Assendon Investments Ltd | Real estate | 2022 |