| MGC Property Developments Limited | Real estate | 2005 |
| MGM Utility Contractors Ltd | Construction | 2016 |
| Mgrb Healthcare Ltd | Health & social care | 2026 |
| MH Haulage (NW) Ltd | Transport & logistics | 2019 |
| MH Project Solutions Limited | Other services | 2022 |
| Mharahuds Real Estate Ltd | Real estate | 2019 |
| MHS Eco Friendly Ltd | Wholesale & retail | 2020 |
| MI Casa Europa Ltd | Professional & scientific | 2020 |
| MI Casa Propiedades Ltd | Real estate | 2023 |
| Mi-Box Limited | Financial services | 2017 |
| Mi-Pac Newco Limited | Professional & scientific | 2014 |
| Mi-Pac Trading Limited | Manufacturing | 2012 |
| MIA & Kalen Limited | Construction | 2019 |
| MIA Amore Pizza Ltd | Hospitality | 2024 |
| Miagee Limited | Construction | 2018 |
| Michael Esson Maxillofacial Services Limited | Health & social care | 2023 |
| Michelle Law Advisory Ltd | Professional & scientific | 2025 |
| Michelle Underwood Limited | Professional & scientific | 2019 |
| Michelmores Directors Limited | Professional & scientific | 1999 |
| Michelmores Group Limited | Extraterritorial | 2018 |
| Michelmores Holdings Limited | Extraterritorial | 2018 |
| Michelmores International Limited | Extraterritorial | 2018 |
| Michelmores Legal Limited | Professional & scientific | 2001 |
| Michelmores LLP | | 2007 |
| Michelmores Nominees Limited | Professional & scientific | 1993 |
| Michelmores Secretaries Limited | Professional & scientific | 1999 |
| Michelmores Services Limited | Extraterritorial | 2018 |
| Michelmores Solicitors Limited | Professional & scientific | 2006 |
| Michelmores Trust Corporation Limited | Other services | 2012 |
| MID Devon Scaffolding Ltd | Construction | 2019 |
| MID Devon Storage Ltd | Real estate | 2022 |
| Middle East Vision Ltd | Professional & scientific | 2024 |
| Middle Farm Poultry Limited | Agriculture & fishing | 2025 |
| Middlemarch Community LED Housing CIC | Administrative & support | 2020 |
| Middleton Bray Estates Ltd | Real estate | 2018 |
| Middleton Bray Group Holdings Ltd | Financial services | 2021 |
| Midhurst Ltd | Real estate | 2022 |
| Midlander Limited | Financial services | 2022 |
| Midmac Services Limited | Administrative & support | 2016 |
| Midmoors Developments Limited | Construction | 2013 |
| Midvale Property Management Limited | Real estate | 2023 |
| Midway Leisure Limited | Real estate | 1995 |
| Mifflin Construction Limited | Construction | 1969 |
| MIG Security and Events Limited | Administrative & support | 2004 |
| MIG Technologies Limited | Administrative & support | 2012 |
| Mighty Devon Cleaning Ltd | Administrative & support | 2025 |
| Miho Analytics Ltd | Information & communication | 2014 |
| Mike Bright and Co Limited | Construction | 1986 |
| Mike Knight Tyres Limited | Wholesale & retail | 2005 |
| Mike MAY Construction Services Ltd | Other services | 2018 |
| Mike Soper Roofing Specialist Ltd | Construction | 2026 |
| Mike Taylor Limited | Extraterritorial | 2009 |
| Mike Wills Limited | Construction | 2014 |
| Mile END House Management Company Limited | Households | 1986 |
| Miles Infinity Ltd | Households | 2017 |
| Milestones Construction Ltd | Construction | 2013 |
| Milk Socials Limited | Professional & scientific | 2024 |
| Milkland C.I.C. | Arts & recreation | 2023 |
| Mill Green Estates Limited | Real estate | 2005 |
| Mill Park Industrial Estate (Management) Limited | Extraterritorial | 2003 |
| Millco Farming Limited | Agriculture & fishing | 2014 |
| Millcote Properties Ltd | Real estate | 2019 |
| Millennium Economics Ltd. | Professional & scientific | 2012 |
| Miller Town & Country Ltd | Real estate | 2013 |
| Mills & SON Limited | Real estate | 2001 |
| Mills & SON Plastering Ltd | Construction | 2025 |
| Millstone Land and Developments Ltd | Construction | 2015 |
| Millstream Court (Exeter) Limited | Households | 2000 |
| Milltop Motors Ltd | Wholesale & retail | 2025 |
| Milner Page Properties Ltd | Real estate | 2022 |
| Mils Legal Ltd | Professional & scientific | 2018 |
| Milton Property Developments Limited | Construction | 2015 |
| Milve Retail Limited | Wholesale & retail | 2013 |
| Mime Heuristics C.I.C. | Education | 2019 |
| Mimicorn Developments Limited | Real estate | 2023 |
| Minch Properties Limited | Households | 1973 |
| Mind and Body Coaching Ltd | Professional & scientific | 2023 |
| Mind for Motion Limited | Arts & recreation | 2017 |
| Mind Mates Coaching Ltd | Other services | 2025 |
| Mind Movement Coaching Ltd | Other services | 2024 |
| Mindazine Ltd | Health & social care | 2010 |
| Mindfully Wild CIC | Education | 2025 |
| Mindset SW Ltd | Education | 2024 |
| Mindset-Southwest Ltd | Education | 2022 |
| Mindshed Ltd | Health & social care | 2025 |
| Mindstream Technologies Limited | Information & communication | 2025 |
| Mine Mart Ltd | Wholesale & retail | 2025 |
| Minerva (Apartments) Management Company Limited | Real estate | 2021 |
| Minerva Roofing Ltd | Construction | 2021 |
| Mini Tennis Stars Limited | Education | 2024 |
| Minnadhu Investments Limited | Financial services | 2022 |
| Mint Apartments Management Ltd | Households | 2002 |
| Minty Green Limited | Professional & scientific | 2014 |
| Minus Gravity Ltd | Professional & scientific | 2014 |
| MIR Couriers Ltd | Transport & logistics | 2025 |
| MIR MM Ltd | Arts & recreation | 2022 |
| MIR23 Limited | Hospitality | 2018 |
| Mira 52 Limited | Hospitality | 2018 |
| Mirok Ltd | Professional & scientific | 2025 |
| Miromutu Investments Ltd | Financial services | 2017 |