| Midlands GAS Flow Ltd | Construction | 2025 |
| Midlands HR Consultancy Ltd | Administrative & support | 2025 |
| Midlands Management Group Ltd | Real estate | 2026 |
| Midlands Mobile Mechanic Ltd | Wholesale & retail | 2025 |
| Midlands MR2 Ltd | Wholesale & retail | 2022 |
| Midlands Optimum Heating Ltd | Construction | 2019 |
| Midlands Riding Club Ltd | Other services | 2026 |
| Midstaffselectrical Ltd | Construction | 2020 |
| Midweb Digital Limited | Professional & scientific | 2019 |
| Midwinter Solutions Limited | Administrative & support | 2013 |
| Mighty Zebra Limited | Extraterritorial | 2014 |
| MIH Group Ltd | Professional & scientific | 2011 |
| MIH Trans Ltd | Transport & logistics | 2015 |
| Mihael 2005 Ltd | Transport & logistics | 2015 |
| Mihai Games Limited | Information & communication | 2025 |
| Mike Peel Tennis Limited | Education | 2026 |
| Mile Away Properties Limited | Real estate | 2002 |
| Miles Dosher Limited | Other services | 2015 |
| Milko Transport Limited | Transport & logistics | 2020 |
| Miller & Watson Carpentry Limited | Construction | 2005 |
| Miller & Watson Trustees Limited | Administrative & support | 2022 |
| Miller Rock Developments Limited | Construction | 2024 |
| Millers Construction Group Limited | Construction | 2024 |
| Mills Stone Engineering Limited | Professional & scientific | 2012 |
| Milton Maine Real Estate Limited | Real estate | 2024 |
| Mimi Filous Limited | Wholesale & retail | 2026 |
| Mimosa (UK) Limited | Real estate | 1991 |
| Mind the Robot Ltd | Information & communication | 2026 |
| Ming Wang Limited | Professional & scientific | 2008 |
| Miniland Ltd | Wholesale & retail | 2015 |
| Minimarket Burton Ltd | Wholesale & retail | 2026 |
| Ministry Ches Limited | Wholesale & retail | 2024 |
| Ministry of Doughnuts Ltd | Hospitality | 2025 |
| Mintech Inspection Services (MIS) Ltd | Professional & scientific | 2025 |
| Miqbal Financial Limited | Professional & scientific | 2014 |
| Mirac C Ltd | Hospitality | 2026 |
| Miraden Car Service & Recovery Ltd | Wholesale & retail | 2025 |
| Mirhayaz Ltd | Wholesale & retail | 2024 |
| Mirpur Motors Ltd | Wholesale & retail | 2023 |
| Mirus Care Ltd | Health & social care | 2023 |
| Mirus Healthcare Limited | Health & social care | 2012 |
| Mirus Housing Ltd | Real estate | 2013 |
| Mishima Limited | Wholesale & retail | 2020 |
| Mitchell Denbeigh Limited | Real estate | 2020 |
| Mixed Freight Haulage Ltd | Transport & logistics | 2022 |
| MJ Car Body Repairs Ltd | Manufacturing | 2025 |
| MJ Trading Limited | Wholesale & retail | 2009 |
| MJD Financial Advisory Ltd | Professional & scientific | 2021 |
| MJD Recruitment Ltd | Administrative & support | 2023 |
| MJD Tyre Recycle Ltd | Wholesale & retail | 2023 |
| MJH GAS Ltd | Other services | 2018 |
| Mjlh Property Services Limited | Real estate | 2019 |
| MK Medical Ambulance Transport Limited | Transport & logistics | 2025 |
| MK Medical Event Services Limited | Health & social care | 2025 |
| MK Medical Group Limited | Health & social care | 2023 |
| MK Medical Training Academy Limited | Education | 2025 |
| MKA Outlet Ltd | Wholesale & retail | 2024 |
| ML Pension Trust Limited | Professional & scientific | 1969 |
| ML Pension Trustees Limited | Professional & scientific | 2018 |
| ML Pensions Limited | Professional & scientific | 1969 |
| MM Stars Ltd | Transport & logistics | 2025 |
| Mmhhs Ltd | Real estate | 2024 |
| MMP Storage & Tyre Sales Ltd | Transport & logistics | 2017 |
| MMS Express Ltd | Transport & logistics | 2019 |
| MNJ Trades UK Ltd | Wholesale & retail | 2026 |
| Mo'Bay Restaurant Ltd | Hospitality | 2019 |
| Mobile Homes Abroad (Holdings) Limited | Financial services | 2007 |
| Mobile Homes Abroad Limited | Wholesale & retail | 2005 |
| Mobile Homes UK Ltd | Financial services | 2008 |
| Modcon Building Solutions Limited | Construction | 2013 |
| Modelmix Ltd | Wholesale & retail | 2026 |
| Modest Fashion Group Ltd | Wholesale & retail | 2025 |
| Modiri Construction Limited | Construction | 2015 |
| Modwena Dental Limited | Health & social care | 2019 |
| Modwena Holdings Limited | Financial services | 2026 |
| MOH H Services Limited | Construction | 2025 |
| Moldo Transport Limited | Wholesale & retail | 2024 |
| MOLDO1987 Ltd | Transport & logistics | 2025 |
| Molly's Enterprise Ltd | Other services | 2014 |
| Molson Coors Global Trading Limited | Administrative & support | 2001 |
| Mona Traders Ltd | Administrative & support | 2022 |
| Monarch Painters Limited | Construction | 2022 |
| Monel Energy 2 Limited | Mining & quarrying | 2024 |
| Monel Energy Limited | Mining & quarrying | 2024 |
| Monel Homes 2 Limited | Real estate | 2025 |
| Monel Homes Limited | Real estate | 2019 |
| Monika Brickwise Holdings Ltd | Real estate | 2025 |
| Moniqueboutique Limited | Wholesale & retail | 2025 |
| Monkey Puzzle Day Nursery (Newtown) Limited | Education | 2008 |
| Monolith Mind Ltd | Wholesale & retail | 2025 |
| Montari Ltd | Professional & scientific | 2025 |
| Monterey Media Limited | Professional & scientific | 2018 |
| Monty Bidco Limited | Financial services | 2019 |
| Monty Midco 1 Limited | Financial services | 2019 |
| Monty Midco 2 Limited | Financial services | 2019 |
| Monty Topco Limited | Financial services | 2019 |
| MOP Vehicles Limited | Wholesale & retail | 2025 |
| Mora Trans Ltd | Administrative & support | 2017 |
| Morar Logistics Ltd | Transport & logistics | 2025 |
| More Naturally Ltd | Professional & scientific | 2026 |