| Micem UK Ltd | Manufacturing | 2022 |
| Michael 27 Limited | Wholesale & retail | 2019 |
| Michael Arthur Ltd | Wholesale & retail | 2015 |
| Michael Boyd TM Ltd | Other services | 2020 |
| Michael Burtscher Consulting Ltd | Professional & scientific | 2015 |
| Michael Commodities Ltd | Wholesale & retail | 2026 |
| Michael Courtney Productions Ltd | Arts & recreation | 2011 |
| Michael Foods Ltd | Hospitality | 2022 |
| Michael Graham Young Limited | Real estate | 2002 |
| Michael Hardy E.R. Services Limited | Financial services | 2018 |
| Michael Harper Limited | Administrative & support | 2025 |
| Michael Hedges Limited | Health & social care | 2006 |
| Michael John Construction Limited | Wholesale & retail | 2001 |
| Michael John Consultants Limited | Professional & scientific | 2001 |
| Michael John Hague Ltd | Extraterritorial | 2025 |
| Michael Krissel | Information & communication | 2022 |
| Michael L Williams Ltd | Information & communication | 2014 |
| Michael LEE Building and Carpentry Ltd | Construction | 2024 |
| Michael M Courier Ltd | Other services | 2020 |
| Michael Robinson Associates Limited | Financial services | 2009 |
| Michael Shore Limited | Wholesale & retail | 2025 |
| Michael Shorten Limited | Information & communication | 2015 |
| Michaelgrey Limited | Transport & logistics | 2025 |
| Michaelston Management 2024 CIC | Households | 2024 |
| Michaelston Y Fedw Internet CIC | Information & communication | 2017 |
| Michartin Co Limited | Manufacturing | 2022 |
| Michele Hope Limited | Administrative & support | 2011 |
| Michele Tani Ltd | Wholesale & retail | 2025 |
| Michelle Marshall Cardiff Ltd | Other services | 2019 |
| Michelle Marshall Ltd | Other services | 2012 |
| Michigan Construction Limited | Construction | 2007 |
| Michino Crop Nutrition UK Ltd | Extraterritorial | 2023 |
| Mick's Tidy UP Ltd | Water & waste | 2016 |
| Micmi Foodstuff Limited | Hospitality | 2024 |
| Micogakin Ltd | Construction | 2020 |
| Micoli Finance Limited | Professional & scientific | 2021 |
| Micro China Warehouse Limited | Professional & scientific | 2020 |
| Micro Doghouse Ltd | Hospitality | 2017 |
| Micro Highstreets CIC | Hospitality | 2025 |
| Micrograpple Limited | Professional & scientific | 2026 |
| Microhubs Limited | Transport & logistics | 2021 |
| Microlox Limited | Real estate | 2021 |
| Microna Investments Limited | Extraterritorial | 1955 |
| Microskin PLC | Manufacturing | 2012 |
| MICROSTORE1 Ltd | Wholesale & retail | 2023 |
| Mictee Ltd | Construction | 2019 |
| Micyber & Partners PC | | 2019 |
| MID Kent Fencing Ltd | Construction | 2019 |
| MID Wales Sport Partnership Limited | Arts & recreation | 2024 |
| Mid-Air Air Conditioning Ltd | Construction | 2016 |
| Mida Group Ltd | Financial services | 2021 |
| Mida Management Limited | Construction | 2020 |
| Midah Consultancy Limited | Information & communication | 2018 |
| Midas Business Solutions Ltd | Information & communication | 2007 |
| Midas Touch Archive Limited | Other services | 2020 |
| Midaz Electrical Limited | Energy | 2013 |
| Midblue Ltd | Wholesale & retail | 2025 |
| Middle East 119 Ltd | Wholesale & retail | 2026 |
| Middle East Human Rights Association | Education | 2025 |
| Middle J Consultancy Limited | Financial services | 2014 |
| Middlerz Ltd | Professional & scientific | 2018 |
| Middlesex Kitchen & Bedroom Limited | Construction | 2016 |
| Middleton Building & Renovation Ltd | Construction | 2018 |
| Middleton Roofing Services Limited | Construction | 2020 |
| Mideiva Limited | Public administration | 2022 |
| Midfield Technical Services Limited | Administrative & support | 2013 |
| Midh Consultancy Ltd | Professional & scientific | 2025 |
| Midi Finance Ltd | Financial services | 2016 |
| Midica Marketing Ltd | Administrative & support | 2025 |
| Midion Limited | Information & communication | 2016 |
| Midland Estate and Tax Law Ltd | Professional & scientific | 2020 |
| Midland International Couriers Limited | Transport & logistics | 2018 |
| Midland Kebabs (Derby) Ltd | Hospitality | 2017 |
| Midland Recovery and Transport Ltd | Transport & logistics | 2019 |
| Midlands BAE Ltd | Health & social care | 2018 |
| Midlands Commodities Ltd | Wholesale & retail | 2016 |
| Midlands Creatives Limited | Administrative & support | 2017 |
| Midlands Halal Meat Ltd | Wholesale & retail | 2016 |
| Midlands Magic Store Limited | Wholesale & retail | 2017 |
| Midlandscarecompany Ltd | Health & social care | 2018 |
| Midnightrainhandmade Ltd | Wholesale & retail | 2025 |
| Midst Energi Ltd | Other services | 2019 |
| Midvital Ltd | Financial services | 2022 |
| Midwifery Matters Limited | Health & social care | 2025 |
| Midynamics Ltd | Information & communication | 2019 |
| Mier Textile Company Limited | Professional & scientific | 2012 |
| Mifan International Ltd | Information & communication | 2021 |
| MIG Consultants Limited | Financial services | 2014 |
| Migamod Ltd | Other services | 2024 |
| Migdal Flooring Limited | Construction | 2015 |
| Mighty Big Bites Limited | Hospitality | 2025 |
| Mighty COD Ltd | Hospitality | 2019 |
| Mighty Dragon Properties Ltd | Real estate | 2026 |
| Mighty EMU Studios Ltd | Information & communication | 2011 |
| Mighty Health Care Limited | Public administration | 2020 |
| Mighty Sky Film Ltd | Information & communication | 2014 |
| Mighty Visage Studios Limited | Information & communication | 2009 |
| Mightybits Ltd | Information & communication | 2024 |
| Migraine Media Ltd | Information & communication | 2025 |
| Migrant Legal Project Limited | Professional & scientific | 2011 |