| Medaax Limited | Wholesale & retail | 2007 |
| Media 1 Productions EOT Trustee Limited | Other services | 2023 |
| Media 1 Productions Limited | Administrative & support | 2001 |
| Media Excellence Ltd | Professional & scientific | 2012 |
| Media Investment Management Ltd. | Professional & scientific | 2010 |
| Mediafour Limited | Information & communication | 2002 |
| Mediamates Limited | Professional & scientific | 2006 |
| Mediamates Productions Limited | Extraterritorial | 2013 |
| Mediate Health Consulting Limited | Professional & scientific | 1999 |
| Mediation North Limited | Other services | 2018 |
| Medica Forte Ltd | Health & social care | 2014 |
| Medical Statistics Consultancy Ltd | Professional & scientific | 2018 |
| Medical Technology Talent Limited | Administrative & support | 2025 |
| Medicines Discovery Catapult Limited | Professional & scientific | 2015 |
| Medicines Discovery Catapult Services Commercial Limited | Professional & scientific | 2021 |
| Medicines Discovery Ventures Limited | Professional & scientific | 2024 |
| Medico-Legal PA Ltd | Administrative & support | 2024 |
| Mediterranean Import Export Limited | Wholesale & retail | 2016 |
| Medo Cafe Limited | Hospitality | 2025 |
| Medologie Limited | Education | 2015 |
| Medorci Ltd | Professional & scientific | 2018 |
| Medrus Pharma Consulting Limited | Professional & scientific | 2018 |
| Medumond Limited | Professional & scientific | 2026 |
| Meet the World Limited | Professional & scientific | 2019 |
| Megafone Communications Limited | Administrative & support | 2004 |
| Megatronic Ltd | Information & communication | 2026 |
| Megtor Limited | Financial services | 2019 |
| Mellington Estates Limited | Construction | 2009 |
| Mellington Investments Limited | Real estate | 2018 |
| Memento Mori 1 Ltd | Wholesale & retail | 2025 |
| Menna Fitzpatrick Ltd | Arts & recreation | 2021 |
| Menorca Gold Limited | Administrative & support | 2000 |
| Menrva Limited | Professional & scientific | 2008 |
| Merchant Connect Ltd | Professional & scientific | 2023 |
| Mercian Limited | Wholesale & retail | 2004 |
| Meridian Healthcomms Holdings Limited | Financial services | 2018 |
| Meridian Healthcomms Limited | Professional & scientific | 2004 |
| Merx Cheshire Limited | Wholesale & retail | 2018 |
| Meta Lounge Holdings Limited | Financial services | 2025 |
| Meta Lounge Limited | Professional & scientific | 2022 |
| Meta Sofa Limited | Wholesale & retail | 2023 |
| Metcalfe Court Romiley RTM Company Limited | Households | 2013 |
| Meteor Consulting Limited | Financial services | 2015 |
| Metro Plumb Ltd | Extraterritorial | 2021 |
| Metro ROD Limited | Construction | 2001 |
| Metropolitan Accommodate Limited | Extraterritorial | 2003 |
| MG (Cheshire) UK Ltd | Wholesale & retail | 2019 |
| MG Badders Ltd | Education | 2017 |
| Mgmt Green Star Ltd | Energy | 2014 |
| Mgmt Infrastructure Ltd | Professional & scientific | 2020 |
| Mgmt Investments Ltd | Professional & scientific | 2024 |
| Mgmt Ltd | Extraterritorial | 2013 |
| MGS Automotive Ltd | Wholesale & retail | 2021 |
| MGX2 Ltd | Real estate | 2010 |
| MH Cancellations Ltd | Other services | 2019 |
| MH Drafting Limited | Professional & scientific | 2007 |
| MIA James Interiors Limited | Professional & scientific | 2024 |
| Mia's Treacle Bites Ltd | Hospitality | 2023 |
| Mia’S American Kitchen Ltd | Hospitality | 2026 |
| Michael Hart and Company Limited | Real estate | 2003 |
| Michael Sherry Limited | Professional & scientific | 2015 |
| Michael Symmons Roberts Limited | Arts & recreation | 2001 |
| Michael's Nook Management Company Limited | Households | 2006 |
| Michel Emerson Limited | Professional & scientific | 2019 |
| Michelle Wilkins Ltd | Professional & scientific | 2024 |
| Middlemiss Consultancy Limited | Professional & scientific | 2017 |
| Mike Fairbanks Limited | Wholesale & retail | 2008 |
| Mike-Orton.Net Limited | Information & communication | 2019 |
| Mikkymore Xclusive Limited | Transport & logistics | 2025 |
| Mil-Tek (UK) Limited | Financial services | 1999 |
| Milan Trading Design Ltd | Wholesale & retail | 2019 |
| Miles Park Global Ltd | Wholesale & retail | 2016 |
| Mill Cottages Management Limited | Real estate | 2003 |
| Millbank Place (Bestwood) Management Company Limited | Households | 2006 |
| Millbrook Property Investments Limited | Real estate | 2016 |
| Miller Economics Ltd | Professional & scientific | 2015 |
| Millers Court RTM Company Limited | Households | 2010 |
| Millesime Art Ltd | Wholesale & retail | 2026 |
| Millie Landscapes & Maintenance Ltd | Professional & scientific | 2020 |
| Millstone Country Inn Ltd | Hospitality | 2015 |
| Millstone Hotel Collection Ltd | Hospitality | 2020 |
| Millward & Keeling Limited | Manufacturing | 2011 |
| Milly Contract Furnishings Limited | Wholesale & retail | 2020 |
| Milner & Ball Properties Ltd | Construction | 2025 |
| Milner Civils Ltd | Construction | 2024 |
| Mimas Estates Ltd | Real estate | 2023 |
| Mind's EYE Psychiatric Solutions Ltd. | Health & social care | 1999 |
| Minevco Holdings Limited | Professional & scientific | 1995 |
| Minevco Limited | Real estate | 1974 |
| Mini Off-Rovers Ltd | Other services | 2022 |
| Mini Stacks Ltd | Hospitality | 2025 |
| Mini Toy Factory Ltd. | Manufacturing | 2024 |
| Miniminx Limited | Wholesale & retail | 2024 |
| Minshull's Garden Centre Limited | Wholesale & retail | 2017 |
| Mintfirsts Limited | Wholesale & retail | 2019 |
| Miopel House Ltd | Wholesale & retail | 2025 |
| MIS Sold PCP Ltd | Administrative & support | 2021 |
| Misfitz Supplements Ltd | Arts & recreation | 2022 |
| Miss Baines Aesthetics Limited | Extraterritorial | 2016 |
| Mission Management Limited | Information & communication | 2010 |