| Lyons Legacy Ltd | Real estate | 2023 |
| Lyons Property Investments Ltd | Real estate | 2025 |
| M & a MM Ltd | Wholesale & retail | 2020 |
| M & D Dwellings Limited | Real estate | 2021 |
| M & D Price Attractions Limited | Arts & recreation | 2018 |
| M & D Price Leisure Limited | Arts & recreation | 2018 |
| M & D Property Improvements Ltd | Construction | 2004 |
| M & D Publicans Limited | Hospitality | 2017 |
| M & E Pristine Clean Ltd | Administrative & support | 2025 |
| M & G Developers Limited | Real estate | 2000 |
| M & L Trenching Limited | Professional & scientific | 2001 |
| M & M Healthcare Providers Ltd | Health & social care | 2012 |
| M & M Leisure & Events Management Ltd | Hospitality | 2024 |
| M & R Rail Ltd | Construction | 2014 |
| M & S Quality Care Ltd | Health & social care | 2019 |
| M a Food (Portsmouth) Limited | Wholesale & retail | 2011 |
| M a Tapas Ltd | Hospitality | 2024 |
| M and B Partners Ltd | Professional & scientific | 2023 |
| M and D Associates Ltd | Professional & scientific | 2025 |
| M and J Medical Services Limited | Health & social care | 2013 |
| M and S Partners Ltd | Wholesale & retail | 2013 |
| M and T Surfacing Ltd | Construction | 2026 |
| M Capital Assets Ltd | Real estate | 2017 |
| M F S 1 Limited | Real estate | 2025 |
| M FIX Limited | Construction | 2013 |
| M G Dixon Services Limited | Professional & scientific | 2013 |
| M Hardy Holdings Limited | Financial services | 2022 |
| M I R Catering Ltd | Hospitality | 2022 |
| M J H Removals Ltd | Transport & logistics | 2002 |
| M J H Screening Program Ltd | Transport & logistics | 2017 |
| M J Robinson Grp/Composite Limited | Construction | 2014 |
| M K Ambulance Service Ltd | Transport & logistics | 2022 |
| M K J Plastering Ltd | Construction | 2015 |
| M L (UK) Dredging Limited | Construction | 1979 |
| M L Fixings Limited | Wholesale & retail | 2023 |
| M Likely Construction Services Limited | Construction | 2007 |
| M Lounge Restaurant Ltd | Hospitality | 2019 |
| M Pro Recruitment Ltd | Administrative & support | 2021 |
| M R Audio Visual Lighting Ltd | Extraterritorial | 2017 |
| M R F Enterprise Limited | Professional & scientific | 1995 |
| M Roberts Events Ltd | Arts & recreation | 2023 |
| M Welton Electrical Ltd | Construction | 2017 |
| M Works International Ltd | Information & communication | 2024 |
| M&D Attractions Ltd | Arts & recreation | 2024 |
| M&D Price Lettings Ltd | Real estate | 2024 |
| M&E Giants Recruitment Limited | Administrative & support | 2025 |
| M&E Services for YOU Ltd | Transport & logistics | 2017 |
| M&G Events Limited | Administrative & support | 2022 |
| M&L Pleasure Fairs Ltd | Arts & recreation | 2022 |
| M&Lp Family Properties Ltd | Real estate | 2025 |
| M&M Contractors Southern Limited | Manufacturing | 2022 |
| M&M Facilities Management Limited | Construction | 2022 |
| M&N Autos (Portsmouth) Ltd | Professional & scientific | 2010 |
| M&R Cleaning Services Hampshire Ltd | Administrative & support | 2022 |
| M&S Lyons Ltd | Administrative & support | 2010 |
| M. Qasim Trades Limited | Wholesale & retail | 2025 |
| M. W. Electrical Services (Hampshire) Limited | Construction | 2008 |
| M.G. Meaden Limited | Construction | 2010 |
| M.J. Warrington & Sons Limited | Construction | 2009 |
| M.J.M. Inns Limited | Wholesale & retail | 1997 |
| M.Lawrence and Sons Ltd | Manufacturing | 2017 |
| M.R. Electrical Services Limited | Construction | 1998 |
| M.R. Painting & Cleaning Services Ltd | Construction | 2026 |
| M.R. Windows, Doors & Conservatories Ltd | Construction | 2019 |
| M.W. Consultants Limited | | 1992 |
| M2 Living & Build Ltd | Construction | 2025 |
| M2 Projects Ltd | Construction | 2023 |
| M27 Properties Ltd | Households | 2024 |
| MA Site Management Ltd | Professional & scientific | 2016 |
| MAA Capital Ltd | Real estate | 2022 |
| MAA Trading Ltd | Wholesale & retail | 2019 |
| MAAG4 EOD Solutions Limited | Professional & scientific | 2024 |
| Maaj Investment Group Ltd | Real estate | 2025 |
| Maarva Limited | Wholesale & retail | 2023 |
| Maasive.Marketing Limited | Professional & scientific | 2025 |
| Mabe Business Centre Ltd | Real estate | 2021 |
| Mabel Homes Hampshire Ltd | Construction | 2025 |
| Mable Facades Brickwork & Cladding Ltd | Construction | 2013 |
| Mablethorpe GP Limited | Health & social care | 2015 |
| MAC & SON Management Ltd | Professional & scientific | 2016 |
| MAC Media Production Limited | Information & communication | 2012 |
| MAC Motors MOT Centre Limited | Professional & scientific | 2018 |
| Maca Project Solutions Ltd | Professional & scientific | 2024 |
| Mackie Holdings Limited | Financial services | 2021 |
| Maclaurin Maritime Limited | Administrative & support | 2012 |
| Macmillan Holdings Ltd | Financial services | 2022 |
| Macmillan Management Limited | Information & communication | 2015 |
| Macmillans Black Book Limited | Professional & scientific | 2026 |
| Macmull Consultancy Ltd | Information & communication | 2016 |
| Macoma Engineering Ltd | Professional & scientific | 2024 |
| MACREPAIRS4U Limited | Other services | 2024 |
| Macro Fabrications Limited | Manufacturing | 2020 |
| Macrovision Property Ltd | Real estate | 2024 |
| Mactek Systems Limited | Manufacturing | 1988 |
| Mactheforks Ltd | Construction | 2014 |
| Macvere Land Rights Ltd | Professional & scientific | 2026 |
| Macvere Ltd | Financial services | 2026 |
| Macvere Property Ltd | Real estate | 2026 |
| Macvere Utility Consultants Ltd | Professional & scientific | 2024 |
| MAD AS a Box of Frogs Limited | Manufacturing | 2019 |