| Masterpursuit Ltd | Wholesale & retail | 2021 |
| Masters Communications Ltd. | Information & communication | 2017 |
| Masters Design LAB Ltd | Education | 2025 |
| Masters Electrical Services Ltd | Construction | 2019 |
| Masterwork Aoitek Tech Corp Ltd | Wholesale & retail | 2026 |
| Mastery Digital NL Ltd | Wholesale & retail | 2025 |
| Mastic Global Ltd | Construction | 2013 |
| Mastique Design Master Limited | Manufacturing | 2025 |
| Masuria Group Ltd | Wholesale & retail | 2020 |
| Mata Services Ltd | Information & communication | 2015 |
| Matadia Entertainment Limited | Information & communication | 2026 |
| Matafics Limited | Education | 2022 |
| Matasa Freight Services UK Ltd | Transport & logistics | 2024 |
| Matasa Trading Ltd | Wholesale & retail | 2025 |
| Matchday Tickets Limited | Other services | 2020 |
| Matchframe Editing Limited | Information & communication | 2015 |
| Matchless Machines Limited | | 1955 |
| Matchmovers VFX Ltd | Information & communication | 2026 |
| Matchpride Caterers Limited | | 1986 |
| Matei Building Pro Ltd | Construction | 2026 |
| Material Queer CIC | Arts & recreation | 2023 |
| Maternally Wellbeing Services Limited | Administrative & support | 2023 |
| Mateuszadam Ltd | Professional & scientific | 2025 |
| Mathew Tench Architects and Associates Ltd. | Professional & scientific | 2013 |
| Mathias 45 Ltd | Wholesale & retail | 2021 |
| Mathias Consultancy Limited | Professional & scientific | 2021 |
| Mathieson Supply Management Ltd | Education | 2017 |
| Matifab Ltd | Information & communication | 2019 |
| Matipa Care Ltd | Health & social care | 2018 |
| Matkad Ltd | Professional & scientific | 2018 |
| Matmazel Luxe Ltd | Wholesale & retail | 2025 |
| Matorama | Professional & scientific | 2024 |
| Matou Service Ltd | Other services | 2017 |
| Matoular Services Ltd | Administrative & support | 2021 |
| Matrex E-Comerece Ltd | Information & communication | 2024 |
| Matrimonio Ltd | Wholesale & retail | 2019 |
| Matrix Care Ltd | Health & social care | 2023 |
| Matrix Engineering Solutions Limited | Professional & scientific | 2000 |
| Matrix Machinery Supplies Ltd | Wholesale & retail | 2019 |
| Matrix Medical Solutions Limited | Health & social care | 2020 |
| Matrix Quotations Ltd | Construction | 2025 |
| Matrix Systems Innovations Ltd | Information & communication | 2024 |
| Matsho Ventures Ltd | Wholesale & retail | 2026 |
| Matsland Limited | Professional & scientific | 2002 |
| Matson Enterprise Ltd | Wholesale & retail | 2026 |
| Matsudai Ramen Ltd | Hospitality | 2019 |
| Matt Appleby Consulting Limited | Professional & scientific | 2019 |
| Matt Evans Private Wealth Ltd | Financial services | 2025 |
| Matt Lesniewski Ltd | Information & communication | 2023 |
| Matt Parry Promotions Limited | Real estate | 2014 |
| Matt Stanger Limited | Construction | 2017 |
| Matt West Consulting Ltd | Information & communication | 2013 |
| Matte VII Labs Ltd | Professional & scientific | 2025 |
| Matterhorn Management Services Limited | Real estate | 2023 |
| Mattervalue Limited | Manufacturing | 1999 |
| Matteyn 1 Ltd | Professional & scientific | 2009 |
| Matteyn 3 Ltd | Professional & scientific | 2009 |
| Matthew a Clark Limited | Health & social care | 2006 |
| Matthew John Stevens Limited | Other services | 2023 |
| Matthew Watkins Ltd | Professional & scientific | 2013 |
| Matthieu Michel Limited | Information & communication | 2014 |
| Mattison ELM Ltd | Real estate | 2015 |
| Mattreyn Media Ltd | Information & communication | 2025 |
| Mattys Transport and Removals Ltd | Transport & logistics | 2018 |
| Mature Dental Ltd | Health & social care | 2019 |
| Maty's Fashion Ltd | Wholesale & retail | 2019 |
| MAU Management Ltd. | Extraterritorial | 2018 |
| Maunder and Ward HR Specialists Ltd | Administrative & support | 2015 |
| Maunder Marketing Limited | Information & communication | 2017 |
| Maureen VEE Limited | Health & social care | 2020 |
| Mauvemist Ltd | Wholesale & retail | 2025 |
| Mava Fast Food Limited | Hospitality | 2023 |
| Mavaro Ltd | Professional & scientific | 2025 |
| Maveco Limited | Professional & scientific | 2005 |
| Maven Holdings Limited | Construction | 2022 |
| Maven Motor Group Ltd | Administrative & support | 2026 |
| Maven Street Partners Limited | Professional & scientific | 2025 |
| Mavenpacks Ltd | Other services | 2025 |
| Maverick Accommodation Ltd | Real estate | 2023 |
| Maverick Corporation Ltd | Wholesale & retail | 2026 |
| Maverick One Media Ltd | Administrative & support | 2016 |
| Maverick Trade Limited | Wholesale & retail | 2022 |
| Maverick-Av Limited | Information & communication | 2014 |
| Mavi Mavi Ltd | Hospitality | 2025 |
| Mavico Logistics Ltd | Transport & logistics | 2020 |
| Mavill Ltd | Hospitality | 2018 |
| Mavin Powercube Limited | Information & communication | 2019 |
| Mavino Ltd | Wholesale & retail | 2025 |
| Mavriton PC | | 2017 |
| MAW Properties Limited | Hospitality | 2003 |
| MAW Property Management Ltd | Real estate | 2020 |
| Mawadah and Rahmah Ltd | Education | 2024 |
| Mawaisdriver Limited | Transport & logistics | 2025 |
| Mawazik Trading Limited | Wholesale & retail | 2025 |
| Mawm Trustees Limited | Extraterritorial | 2025 |
| MAX D&C Ltd | Administrative & support | 2022 |
| MAX Drake Medical Herbalist Ltd | Health & social care | 1997 |
| MAX Estates Limited | Hospitality | 2000 |
| MAX Fabrications Limited | Manufacturing | 2011 |
| MAX Facilities Ltd | Administrative & support | 2025 |