| Mexim Limited | Professional & scientific | 1996 |
| MF Accounting Limited | Professional & scientific | 2024 |
| Mgwj Consulting Ltd | Professional & scientific | 2024 |
| MH Food Group Ltd | Hospitality | 2026 |
| MH Kingswood Assets (BTL) Ltd | Real estate | 2021 |
| MH Kingswood Assets Ltd | Real estate | 2019 |
| MH Taxis Ltd | Wholesale & retail | 2024 |
| MHR Business Growth Ltd | Professional & scientific | 2016 |
| MHT Technical Services Ltd | Professional & scientific | 2017 |
| MI Build & Property Ltd | Construction | 2026 |
| MI Ears Ltd | Health & social care | 2019 |
| Micabi Ltd | Transport & logistics | 2017 |
| Michael Andrews Hairdressing Limited | Other services | 2007 |
| Michael Jones Narthex Ltd | Arts & recreation | 2018 |
| Michael Leahy Music Ltd | Arts & recreation | 2026 |
| Michael Smith Engineers Limited | Wholesale & retail | 1971 |
| Michaelandtaniahackett Limited | Health & social care | 2013 |
| Michelle Nails Limited | Other services | 2022 |
| Micro Pro Ltd | Information & communication | 2008 |
| Micro Setting Ltd | Administrative & support | 2007 |
| Micromax Electronic Materials UK Limited | Other services | 2015 |
| Micronook Limited | Information & communication | 2022 |
| MID Surrey Tree Surgery Contractors Limited | Agriculture & fishing | 2015 |
| Middlegap Estates Limited | Construction | 2000 |
| Middleton Performance Centre Ltd | Arts & recreation | 2025 |
| Middleton White Limited | Administrative & support | 2025 |
| Midhope Close Flats Management Company Limited | Households | 1990 |
| Miele Operations & Payment Solutions Limited | Other services | 2020 |
| Mightystay Estates Ltd | Real estate | 2019 |
| Mightystay Property Ltd | Real estate | 2020 |
| MIH Limited | Wholesale & retail | 1981 |
| Mihai Buhoi Ltd | Transport & logistics | 2019 |
| Mihailbls Ltd | Construction | 2018 |
| Mihalev Ltd | Construction | 2017 |
| Mike's Professional Cleaning Ltd | Administrative & support | 2022 |
| Mila Rose Ltd | Administrative & support | 2019 |
| Mile Marketing Limited | Wholesale & retail | 2022 |
| Mile Path (West) Residents' Association Limited(The) | Other services | 1973 |
| Milena Rundle Consulting Limited | Professional & scientific | 2021 |
| Mileo Marketing Ltd | Professional & scientific | 2024 |
| Miles Better Vehicle Solutions Limited | Wholesale & retail | 2006 |
| Miles Builders (UK) Limited | Construction | 2010 |
| Milesworth Homes Ltd | Construction | 2020 |
| Milford Management Services Limited | Financial services | 2013 |
| Milford Plotholders Limited | Real estate | 2012 |
| Military Chauffeur Limited | Administrative & support | 2025 |
| Milkay Holdings Ltd | Financial services | 2026 |
| Millarjay Limited | Information & communication | 2015 |
| Millenium Business Consultancy Ltd | Professional & scientific | 1998 |
| Millman Limited | Wholesale & retail | 1991 |
| Miltenyi Biotec Limited | Manufacturing | 1995 |
| Milton Keynes Theatre Limited | Arts & recreation | 1998 |
| Milturn (Precision Engineers) Limited | Professional & scientific | 2001 |
| Milturn Limited | Financial services | 2014 |
| Mimbridge Memorials Limited | Other services | 2017 |
| Minas Investments Ltd | Financial services | 2026 |
| Minas Properties Ltd | Real estate | 2022 |
| Mind Control Trials Ltd | Manufacturing | 2022 |
| Mind Over Mulligans Ltd | Wholesale & retail | 2024 |
| Mindblaze Consulting Limited | Professional & scientific | 2025 |
| Mini Athletics West Surrey Ltd | Education | 2024 |
| Mini Ballers Woking Ltd | Education | 2025 |
| Ministry Golf Limited | Manufacturing | 2022 |
| Mink Farm Ltd | Agriculture & fishing | 2024 |
| Minoma Ltd | Extraterritorial | 2025 |
| Minotaur Film Ltd | Information & communication | 2015 |
| Minotek I.T. Limited | Information & communication | 1996 |
| Mirage Associates Limited | Professional & scientific | 2005 |
| Mirage Marketing Ltd | Professional & scientific | 2024 |
| Mirak Ltd | Hospitality | 2021 |
| Mireya Group Ltd | Wholesale & retail | 2023 |
| Mirla Properties Ltd | Professional & scientific | 2003 |
| Mischen Ltd | Wholesale & retail | 2015 |
| Mishane Limited | Real estate | 2003 |
| Misra's Corporation Ltd | Real estate | 2021 |
| Miss Bush (Ripley) Limited | Wholesale & retail | 2014 |
| Miss OWL Limited | Wholesale & retail | 2021 |
| Misstake Ltd | Wholesale & retail | 2018 |
| Mistion Limited | Professional & scientific | 2013 |
| MIV Woking Limited | Hospitality | 2018 |
| Mivigilance Limited | Health & social care | 2020 |
| Miwah Ltd | Wholesale & retail | 2025 |
| Mizzelegance Beauty Salons Limited | Other services | 2025 |
| MJ FOX Homes Limited | Construction | 2025 |
| MJ Fresh Ltd | Administrative & support | 2021 |
| Mjcr Ltd | Manufacturing | 2000 |
| MJD Medical Ltd | Health & social care | 2014 |
| MJH Services (Woking) Ltd | Other services | 2015 |
| MJR Travel Consulting Limited | Administrative & support | 2019 |
| MJR Vehicle Solutions Limited | Wholesale & retail | 2022 |
| MK Emporium Ltd | Wholesale & retail | 2025 |
| MK Hire Limited | Professional & scientific | 1998 |
| MK Karting Limited | Wholesale & retail | 2019 |
| MK Luxury Fashion Ltd | Wholesale & retail | 2025 |
| MK Mens Limited | Other services | 2025 |
| MK Sales Limited | Extraterritorial | 2001 |
| Mkamz Trading Ltd | Wholesale & retail | 2024 |
| MKK Rail Limited | Construction | 2017 |
| Mkpastryarts Ltd | Hospitality | 2024 |
| MKS Interiors Ltd | Construction | 2025 |