| Mike Stjohn-Green Consulting Limited | Information & communication | 2012 |
| Mikuni Carruthers Ltd | Information & communication | 2022 |
| Milby Investments Ltd | Real estate | 2013 |
| Miles Professional Health Services Limited | Health & social care | 2019 |
| Mill Pitt Limited | Professional & scientific | 2025 |
| Mill Point Land Limited | Real estate | 2014 |
| Millbank Europe Limited | Manufacturing | 1985 |
| Millbank International Limited | Real estate | 1990 |
| Millbridge Systems Limited | Information & communication | 2010 |
| Millbrook Speciality Coated Papers Limited | Manufacturing | 2018 |
| Millennium Plaza RTM Company Limited | Households | 2013 |
| Milleran Marketing Limited | Wholesale & retail | 1997 |
| Millie Richardson Flowers Ltd | Professional & scientific | 2020 |
| Milliner Assets Ltd | Extraterritorial | 2019 |
| Millipede Ltd | Real estate | 2014 |
| Millpond Developments Ltd | Administrative & support | 2024 |
| Millward Properties Ltd | Real estate | 2008 |
| Millway House (Cheltenham) Ltd | Households | 2026 |
| Millwheel Tack Shop & G.G. Feeds Limited | Wholesale & retail | 2014 |
| Millwood Limited | Wholesale & retail | 2008 |
| Milne Quantum Solutions Ltd | Information & communication | 2024 |
| Milsto Limited | Real estate | 2024 |
| Milton Under Wychwood Property Ltd | Real estate | 2023 |
| Mimy Consulting Ltd | Professional & scientific | 2024 |
| Minall & Mather Ltd | Wholesale & retail | 2021 |
| Minch Dent Ltd | Health & social care | 2018 |
| Mind Body ROW Holdings Limited | Financial services | 2022 |
| Mind Body ROW Limited | Education | 2022 |
| Mind Jobs Limited | Administrative & support | 2013 |
| Mind the AI GAP Ltd | Information & communication | 2025 |
| Mindbody, Ltd. | Information & communication | 2011 |
| Mindful Digital Limited | Wholesale & retail | 2022 |
| Mindful Psychology Limited | Education | 2013 |
| Mindsharp Ltd | Administrative & support | 2024 |
| Mindspring Consultancy Limited | Professional & scientific | 2003 |
| Mindware Consulting Limited | Administrative & support | 2021 |
| Minett's Farm Ltd | Agriculture & fishing | 2019 |
| Mingrui Property Limited | Real estate | 2025 |
| Mini Vip's Nursery & Day Care Ltd | Education | 2015 |
| Minibus Direct UK Limited | Transport & logistics | 2003 |
| Minster Ventures Ltd | Information & communication | 2012 |
| Minter Publishing Limited | Information & communication | 2014 |
| Minton Cheltenham Management Company Limited | Extraterritorial | 2008 |
| Minton Cheltenham Property Management Ltd | Households | 2019 |
| MIR Same Day Couriers Limited | Transport & logistics | 2024 |
| MIR Trans Midlands Ltd | Transport & logistics | 2017 |
| Mirad Education Ltd | Education | 2024 |
| Miranda Catering Ltd | Hospitality | 2019 |
| Mirari Support Services Limited | Administrative & support | 2019 |
| Mirdif Associates Ltd | Professional & scientific | 2022 |
| Miri Capital Limited | Financial services | 2024 |
| Miriad Optical Limited | Financial services | 2026 |
| Miro Consultants Limited | Information & communication | 2003 |
| Mirus Construction Limited | Construction | 2006 |
| Mirus Design & Build Ltd | Construction | 2007 |
| Mischiefworks Ltd | Professional & scientific | 2025 |
| Mish Mash Pictures Limited | Arts & recreation | 2018 |
| Mission Inclusion CIC | Education | 2023 |
| Mistral Holdings Limited | Professional & scientific | 2015 |
| Mistral Holdings Trust Limited | Professional & scientific | 2022 |
| Mitchell Davis Accountants Limited | Professional & scientific | 2023 |
| Mitchell Glanville Limited | Professional & scientific | 2001 |
| Mitchell Psychology Ltd | Health & social care | 2021 |
| Mitchell's Property Investments Ltd | Real estate | 2021 |
| Mithal Consulting Limited | Professional & scientific | 2025 |
| Mitiga-Uk Ltd | Information & communication | 2019 |
| Mitrewick Holdings Ltd | Financial services | 2019 |
| MJ Beauty Ltd | Other services | 2024 |
| MJ Growth Marketing Ltd | Professional & scientific | 2024 |
| MJA Consulting Services Limited | Professional & scientific | 2021 |
| MJB Flooring (Bristol) Limited | Construction | 2003 |
| MJB Works Ltd | Construction | 2005 |
| MJC Cheltenham Limited | Other services | 2010 |
| MJD Consulting Limited | Information & communication | 2002 |
| Mjduff Property Limited | Real estate | 2026 |
| MJL (UK) Ltd | Professional & scientific | 2012 |
| MJP Homes Holdings Limited | Real estate | 2023 |
| MJP Homes Ltd | Real estate | 2016 |
| MJS Sports Consultancy Ltd | Arts & recreation | 2025 |
| MKC Holdings Ltd | Hospitality | 2025 |
| Mklink Holdings Ltd | Real estate | 2017 |
| MLC Transport Limited | Transport & logistics | 1995 |
| Mlmp Ltd | Hospitality | 2020 |
| Mm-Spec Limited | Financial services | 2022 |
| MN 35006 Operations Limited | Administrative & support | 2013 |
| MN340 Limited | Manufacturing | 2020 |
| MN341 Limited | Manufacturing | 2020 |
| MN350 Limited | Real estate | 2022 |
| MN353 Limited | Transport & logistics | 2023 |
| MNC Healthcare Ltd | Health & social care | 2016 |
| MNR Hair Ltd | Other services | 2026 |
| MNR Project Consulting Ltd. | Other services | 2014 |
| Mnsf Business Services Ltd | Real estate | 2022 |
| Mobile Technology Services Ltd | Wholesale & retail | 2026 |
| Mocoo Limited | Hospitality | 2026 |
| Modern Access Limited | Construction | 2024 |
| Modica Gardens Ltd | Administrative & support | 2018 |
| Modu 3D Limited | Professional & scientific | 2025 |
| Modular Building Site Services Ltd | Construction | 2013 |
| Modularity Limited | Information & communication | 2017 |