| Mdrd Ltd | Other services | 2019 |
| MDS Home Improvements Limited | Construction | 2019 |
| MDS Leisure Ltd | Manufacturing | 2020 |
| MDS Water Services Limited | Construction | 2008 |
| MDT Media Limited | Professional & scientific | 2020 |
| Mduyus UK Ltd | Hospitality | 2021 |
| ME Hampshire Cleaning Services Limited | Administrative & support | 2022 |
| Me-Ma World Ltd | Administrative & support | 2022 |
| Meachers Global Logistics Limited | Transport & logistics | 1958 |
| Meachers Group Investments Limited | Professional & scientific | 1995 |
| Mead House Limited | Households | 2005 |
| Meadow Communications Limited | Professional & scientific | 2015 |
| Meadow Events Limited | Administrative & support | 2020 |
| Meadow Lane Hamble Limited | Real estate | 2008 |
| Meadow Property Group Ltd | Real estate | 2016 |
| Meadow Way Limited | Professional & scientific | 2013 |
| Meadowbrook Gardens (Management) Ltd | Households | 2025 |
| Meadowhead Productions Ltd | Information & communication | 2021 |
| Meadows (Locks Heath) Management Limited | Households | 2010 |
| Meadows Signature Care Ltd | Health & social care | 2025 |
| Meadows Yard Limited | Real estate | 2021 |
| Mears Ashby Healthcare Limited | Health & social care | 2023 |
| Measuring and CAD Services LLP | | 2013 |
| Meat Bay (Southampton) Ltd | Hospitality | 2017 |
| MEB Engineering Services Limited | Construction | 2023 |
| MEC Engineers Ltd | Professional & scientific | 2024 |
| MEC Prime Ltd | Hospitality | 2025 |
| Mech-Elec Marine Ltd | Manufacturing | 2019 |
| Mechqs Ltd | Information & communication | 2026 |
| Meco Cars Ltd | Transport & logistics | 2024 |
| Mectec ENG Ltd | Professional & scientific | 2021 |
| Medaegis Ltd | Information & communication | 2025 |
| MEDE5 Solutions Ltd | Information & communication | 2025 |
| Medeea Trans Ltd | Transport & logistics | 2020 |
| Medesence Limited | Health & social care | 2010 |
| Medfield Healthcare Limited | Health & social care | 2024 |
| Media SG Ltd | Professional & scientific | 2023 |
| Mediakind Systems UK Ltd | Information & communication | 1999 |
| Medialux Productions Ltd | Information & communication | 2021 |
| Mediaquest Ltd | Professional & scientific | 2003 |
| Medical Property Developments Limited | Real estate | 1982 |
| Medical Support Offshore Limited | Health & social care | 2007 |
| Medicare Aesthetics Ltd | Health & social care | 2019 |
| Medicare Practice Ltd | Health & social care | 2023 |
| Medicine Clinic Limited | Wholesale & retail | 2006 |
| Medicsgateway Limited | Education | 2025 |
| Medina (M&J) Limited | Real estate | 2013 |
| Medina Court Management Limited | Households | 2000 |
| Medina Marine Services Limited | Manufacturing | 2017 |
| Mediqore Ltd | Administrative & support | 2025 |
| Medisec Ambulance Service Limited | Health & social care | 2011 |
| Mediter Developments (IOW) Ltd | Construction | 2021 |
| Mediterranean Assets Management Ukeig | | 2014 |
| Meditronics Limited | Professional & scientific | 1983 |
| Medsale Brokerage Ltd | Wholesale & retail | 2004 |
| Medvis Ltd | Education | 2021 |
| Meek Marine Services Limited | Construction | 2026 |
| Meemoon Limited | Hospitality | 2021 |
| Meena Plastics Ltd | Manufacturing | 2010 |
| Meeple Village Ltd | Hospitality | 2023 |
| Meet Point Bakery Ltd | Wholesale & retail | 2017 |
| Meeteor Incorporation Limited | Information & communication | 2026 |
| Meeting House Recruitment Limited | Extraterritorial | 2004 |
| Meeting House Sales Limited | Extraterritorial | 2004 |
| Megatradevpn Ltd | Information & communication | 2026 |
| Megginson IT Ltd | Information & communication | 2018 |
| Meghna BD Ltd | Hospitality | 2022 |
| Megmax Limited | Administrative & support | 2007 |
| MEH Agency Limited | Professional & scientific | 2012 |
| Meharunnisa Limited | Hospitality | 2015 |
| Mehran Renovation Services Limited | Construction | 2023 |
| Meihe Investment Ltd | Hospitality | 2025 |
| Meina Ltd | Transport & logistics | 2025 |
| Meiva’S Limited | Transport & logistics | 2026 |
| Mekkmaster Boiler Repair Ltd | Construction | 2025 |
| Mekv Newco Limited | Financial services | 2019 |
| Melbourne Apartments Bedford Limited | Construction | 2016 |
| Melbury Court Management (Southampton) Limited | Households | 1996 |
| Melbury Limited | Hospitality | 2019 |
| Melchet Road 1961 Limited | Extraterritorial | 2014 |
| Melhuish Marine Services Limited | Construction | 2015 |
| Meli Motors Limited | Wholesale & retail | 2025 |
| Melia Technology Limited | Information & communication | 2009 |
| Melior Associates Ltd | Administrative & support | 2015 |
| Meliora Projects Limited | Transport & logistics | 2017 |
| Meliora Wellness Ltd | Wholesale & retail | 2021 |
| Meliorate NOW Ltd | Information & communication | 2019 |
| Melissa Greenwood Coaching Ltd | Other services | 2009 |
| Melissa Megan Photography Limited | Professional & scientific | 2024 |
| Mellor Tree Surgeons Limited | Agriculture & fishing | 2011 |
| Melly (Southampton) Limited | Wholesale & retail | 1986 |
| Melo and Similo Healthcare Ltd | Health & social care | 2017 |
| Melo Persian Restaurant Ltd | Hospitality | 2015 |
| Melorose Private Limited | Health & social care | 2018 |
| Melrose Gardens Residents Association Company Ltd. | Households | 1996 |
| MEM Equity Ltd | Financial services | 2020 |
| Mem-Star Rugged Ltd | Wholesale & retail | 2003 |
| Memorare Ltd | Information & communication | 2026 |
| Memoryjane Healthcare Limited | Health & social care | 2022 |
| Menai Geophysical Consultants Limited | Other services | 1998 |