| MFB Delivery Ltd | Transport & logistics | 2021 |
| MFD Construction Ltd | Construction | 2024 |
| Mfmm Limited | Hospitality | 2022 |
| MG Cars Sale Ltd | Wholesale & retail | 2023 |
| MG Popinn Ltd | Hospitality | 2021 |
| Mg's Engineering Ltd | Manufacturing | 2019 |
| MGA Cover Services Limited | Financial services | 2013 |
| MHARA123 Limited Limited | Health & social care | 2025 |
| MI Commerce Ltd | Wholesale & retail | 2025 |
| MIA Lana Ltd | Wholesale & retail | 2023 |
| Mian Takeaway Ltd | Hospitality | 2025 |
| MIB International Limited | Hospitality | 2026 |
| MIB Maintenance Limited | Construction | 2015 |
| Michael Anthony Consulting Limited | Administrative & support | 2021 |
| Micheal Bush Limited | Information & communication | 2026 |
| Mickel Motorsport Limited | Other services | 2009 |
| Micra Brickwork Ltd | Administrative & support | 2015 |
| Micro Fastenings Limited | Wholesale & retail | 2006 |
| Micro IT Industry Limited | Information & communication | 2024 |
| MID Security Ltd | Construction | 2012 |
| MID Sussex Cars Ltd | Transport & logistics | 2006 |
| Midas G20 Limited | Construction | 2012 |
| Midas Touch Business Services Limited | Information & communication | 2013 |
| Midibo Ltd | Professional & scientific | 2013 |
| Midland Cool Limited | Administrative & support | 2003 |
| Mightech Ltd | Information & communication | 2014 |
| Mihege Limited | Construction | 2011 |
| MII Concept Ltd | Professional & scientific | 2025 |
| Mijagii Ltd | Wholesale & retail | 2010 |
| Milaniya Distributors Ltd | Wholesale & retail | 2020 |
| Mildicom Limited | Information & communication | 2019 |
| Mill Court Management (Crawley) Limited | Real estate | 2001 |
| Mill Therapies Limited | Real estate | 2020 |
| Millards (Accountants & Taxation) Limited | Professional & scientific | 2017 |
| Miller Family Holdings Limited | Real estate | 2025 |
| Millie Shivani Limited | Real estate | 2019 |
| Millmead Management Company Limited | Households | 1988 |
| Millstone UK Limited | Construction | 2001 |
| Millvent Limited | Professional & scientific | 2017 |
| Milton Place Residents Limited | Households | 2013 |
| Mimicme.Global Ltd | Information & communication | 2022 |
| Mimosa Property Investments Ltd | Real estate | 2022 |
| Mind-Set Developments Ltd | Administrative & support | 2016 |
| Mindful Maternity Ltd | Health & social care | 2018 |
| Mindful Nutrition Practice Ltd | Health & social care | 2011 |
| Mindmetic Limited | Information & communication | 2007 |
| Miracle Capital Limited | Financial services | 2025 |
| Mirror Marketing Limited | Professional & scientific | 2011 |
| Mission Control Alpha Ltd | Professional & scientific | 2024 |
| Mister Logistics Ltd | Transport & logistics | 2025 |
| MIT Build Ltd | Construction | 2026 |
| Mitac Europe Ltd | Administrative & support | 2001 |
| Miticivsy Ltd | Transport & logistics | 2019 |
| Mivik Ltd | Wholesale & retail | 2022 |
| Mixx Limited | Manufacturing | 2007 |
| Mizado Trading UK Limited | Wholesale & retail | 2024 |
| MJ IT Ltd | Information & communication | 2023 |
| MJB Land Ltd | Real estate | 2026 |
| MJD Accounting Limited | Professional & scientific | 2022 |
| Mjones Property Ltd | Real estate | 2025 |
| MK MED Ltd | Wholesale & retail | 2013 |
| MK Vision Accountancy Ltd | Professional & scientific | 2012 |
| MK Vision Properties Ltd | Real estate | 2025 |
| MKE Contracts Limited | Construction | 2016 |
| MKG Music Services Limited | Information & communication | 2026 |
| MKM Childcare Limited | Education | 2015 |
| ML and K Services Ltd | Health & social care | 2014 |
| MLB Fire & Security Services Limited | Construction | 2004 |
| MLR Entertainment Ltd | Real estate | 2026 |
| MM Perfect Limited | Construction | 2019 |
| MME Planning Services Ltd | Professional & scientific | 2023 |
| Mmussa Business Limited | Wholesale & retail | 2025 |
| MN Global Ecom Ltd | Wholesale & retail | 2026 |
| MNF Enterprise Ltd | Manufacturing | 2025 |
| Mnili Holdings Ltd | Construction | 2026 |
| MNP Residential Ltd. | Real estate | 2012 |
| Moat Road Dental Care Limited | Health & social care | 2008 |
| Moazam's ALI Ltd | Wholesale & retail | 2025 |
| Mobielecs Ltd | Wholesale & retail | 2024 |
| Mobile Alloy Wheels and Car Scratch Repairs Ltd | Wholesale & retail | 2026 |
| Mocodo Ltd | Wholesale & retail | 2024 |
| Modaka UK Ltd | Wholesale & retail | 2018 |
| Modaphones Limited | Information & communication | 2009 |
| Modcon Project Management Ltd | Professional & scientific | 2024 |
| Model Arte Design Limited | Arts & recreation | 2013 |
| Moderm Limited | Professional & scientific | 2019 |
| Modern Landscaping Limited | Administrative & support | 2026 |
| Modularmarket Ltd | Hospitality | 2026 |
| Moghe Properties Ltd | Real estate | 2020 |
| Moghe Tech PVT Ltd | Information & communication | 2017 |
| Moheen Ltd | Health & social care | 2022 |
| Molloy & Coppendale Building Ltd | Construction | 2026 |
| Molueri Ltd | Real estate | 2025 |
| MON AMI Crawley Limited | Hospitality | 2025 |
| Monami Lounge Ltd | Hospitality | 2022 |
| Monarch Estate Investments Ltd | Real estate | 2024 |
| Monchoori Limited | Hospitality | 2026 |
| Monix Accountancy Ltd | Professional & scientific | 2016 |
| Monix Aerospace Ltd | Manufacturing | 2022 |
| Montclair Distribution Ltd | Wholesale & retail | 2026 |