| Mayflower Global Ltd | Professional & scientific | 2024 |
| Maylo Ltd | Professional & scientific | 2022 |
| Maypole Recruitment Limited | Administrative & support | 2017 |
| MB ROI NO Talo Limited | Wholesale & retail | 2025 |
| MBB Transport Services Ltd | Transport & logistics | 2026 |
| Mbdiffey Services Limited | Professional & scientific | 2021 |
| MBE Training Ltd | Education | 2022 |
| MBN Automotive Ltd | Wholesale & retail | 2019 |
| MBN Negocios Ltd | Information & communication | 2025 |
| MBO Buildings Limited | Real estate | 2021 |
| MBO Records Limited | Information & communication | 1999 |
| MBR Automotive Ltd | Wholesale & retail | 2021 |
| Mbrstore Ltd | Wholesale & retail | 2024 |
| MC Editions Ltd | Information & communication | 2020 |
| MC Performance Centre (Bournemouth) Ltd | Health & social care | 2023 |
| MC Performance Centre Ltd | Extraterritorial | 2023 |
| MC Property Ventures Limited | Construction | 2014 |
| MC Warranty Services Ltd | Financial services | 2019 |
| MCA Associates Ltd | Health & social care | 2019 |
| MCB Management Services Ltd | Real estate | 2021 |
| MCB Takeaway Limited | Hospitality | 2019 |
| MCB Technologies Limited | Information & communication | 2023 |
| MCC Aviation Consulting Services Ltd | Professional & scientific | 2016 |
| Mccarthys Costs Ltd | Professional & scientific | 2022 |
| Mccauley Management Limited | Administrative & support | 2018 |
| Mcdermott Lettings Ltd | Real estate | 2024 |
| Mcemsuccess Limited | Education | 2015 |
| Mcewan Software Ltd | Information & communication | 2021 |
| Mcgowan IE Ltd | Real estate | 2024 |
| Mcintyre Properties ( South) Limited | Real estate | 2014 |
| Mcmorton Limited | Information & communication | 2016 |
| MCOMPOSITES1 Ltd | Manufacturing | 2025 |
| Mcqueen Research Limited | Health & social care | 2009 |
| MCR Group Ltd | Real estate | 2017 |
| MCR Recruitment Limited | Professional & scientific | 2020 |
| Mctechnology Ltd | Information & communication | 2026 |
| MD Jahirul AZZ Ltd | Wholesale & retail | 2025 |
| MD Sports Group Ltd | Arts & recreation | 2017 |
| MD Technology Limited | Administrative & support | 2018 |
| MDC Properties Limited | Real estate | 2019 |
| MDG Fine Arts Limited | Arts & recreation | 2000 |
| MDG Investment Holdings Ltd | Financial services | 2024 |
| MDG Sports Limited | Wholesale & retail | 2011 |
| MDH Build Ltd | Construction | 2025 |
| Mdmht Ltd | Wholesale & retail | 2024 |
| MDS International Transformers Limited | Manufacturing | 2017 |
| MDS Internet Limited | Information & communication | 2005 |
| MDY Holdings Ltd | Financial services | 2025 |
| ME23 Holding Limited | Financial services | 2022 |
| Meadows Kirton Management Company Limited | Households | 2022 |
| Mechanical Estimating Ltd | Professional & scientific | 2023 |
| Mechatronic Assemblies Limited | Manufacturing | 2014 |
| Medara Ltd | Hospitality | 2023 |
| Medbay Apps Ltd | Wholesale & retail | 2026 |
| Medconnect Consultancy Limited | Health & social care | 2024 |
| Medecine Francaise Londres Limited | Extraterritorial | 2011 |
| Medgn Supply Limited | Wholesale & retail | 2024 |
| Medi Supplies Limited | Administrative & support | 2009 |
| Mediabim Ltd | Wholesale & retail | 2013 |
| Medianation Limited | Information & communication | 2024 |
| Medica Pro Ltd | Health & social care | 2023 |
| Medical LAB Clinic Ltd | Health & social care | 2025 |
| Medical Matters North West Limited | Health & social care | 2006 |
| Medical Photonics Limited | Manufacturing | 2024 |
| Medicare Systems Group Ltd | Financial services | 2021 |
| Medilink Solutions Ltd | Health & social care | 2023 |
| Medios Digitales DEL SUR Ltd | Information & communication | 2025 |
| Medisec Services Limited | Administrative & support | 2015 |
| Medjay Empire Ltd | Financial services | 2020 |
| Medley Motley Town Limited | Arts & recreation | 2025 |
| Medlink Students Limited | Administrative & support | 2016 |
| Medrad Group Ltd | Health & social care | 2023 |
| Medsport GB Limited | Administrative & support | 2009 |
| MEE 2 Limited | Construction | 2015 |
| Meed Retail Ltd | Wholesale & retail | 2021 |
| Meela Properties Ltd | Real estate | 2020 |
| Meercats Maine Coon Cattery Dorset Ltd | Agriculture & fishing | 2022 |
| Meet Wendy Ltd | Information & communication | 2026 |
| MEG Languages Limited | Education | 2017 |
| Mega Electrical (Bournemouth) Limited | Construction | 2010 |
| Megabowl Leisure Limited | Administrative & support | 2019 |
| Megadodo Designs Ltd | Manufacturing | 2023 |
| Megavato Ltd | Real estate | 2021 |
| Mehsa Tech Ltd | Wholesale & retail | 2026 |
| Mehson Property Company Limited | Real estate | 1995 |
| Meka Retail Ltd | Wholesale & retail | 2022 |
| MEL Bush Holdings Limited | Financial services | 2022 |
| Melash Group Ltd | Information & communication | 2023 |
| Meldein Projects Ltd | Professional & scientific | 2020 |
| Melesa Limited | Financial services | 2014 |
| Melicia Tech Services Ltd | Information & communication | 2023 |
| Melimoon Studios Ltd | Extraterritorial | 2024 |
| Melivan Drywall Solution Limited | Construction | 2024 |
| Mellery Consulting Limited | Professional & scientific | 2016 |
| Mello Digital Ltd | Information & communication | 2025 |
| Mellors Management Consultancy Ltd | Professional & scientific | 2023 |
| Melo-M Creative Ltd | Professional & scientific | 2025 |
| Melodies in Motion Ltd | Extraterritorial | 2011 |
| Melody Box Limited | Financial services | 2000 |
| Melonade Media Ltd | Information & communication | 2007 |