| Majestic Bingo Online Holdings Limited | Financial services | 2019 |
| Majint Limited | Professional & scientific | 2026 |
| Makeup Ministries Limited | Education | 2017 |
| Makrocki Transport Ltd | Transport & logistics | 2014 |
| Maku Service Ltd | Transport & logistics | 2024 |
| Mallow Close 1972 Limited | Extraterritorial | 2014 |
| Mama Liz's Limited | Hospitality | 2008 |
| MAN Made Foods Ltd. | Manufacturing | 2013 |
| Manger Equine Ltd | Agriculture & fishing | 2018 |
| Maniek Transport Ltd | Transport & logistics | 2026 |
| Mann and SON Scaffolding Ltd | Construction | 2020 |
| Manor Fresh Limited | Wholesale & retail | 2005 |
| Manor Multibuild Ltd | Construction | 2024 |
| Manor Rooflines Limited | Construction | 2025 |
| Mantruck Ltd | Transport & logistics | 2025 |
| Maple Properties & Rentals Ltd | Real estate | 2022 |
| Maplethorpe & Mooney Ltd | Construction | 2016 |
| Maplethorpe Builders Ltd | Construction | 2019 |
| MAR Trans (Lincs) Ltd | Transport & logistics | 2021 |
| Marant Development Limited | Construction | 2014 |
| Maratiron Ltd | Transport & logistics | 2018 |
| Marcoci UK Limited | Transport & logistics | 2016 |
| Marden Puiu Ltd | Transport & logistics | 2021 |
| Mare Transport Ltd | Transport & logistics | 2018 |
| Margaret-Rose Apothecary Limited | Wholesale & retail | 2011 |
| Maria Louisa (Sofia) Management Company Ltd | Administrative & support | 2019 |
| Marian Drivers Limited | Transport & logistics | 2018 |
| Marian Invest Ltd | Real estate | 2025 |
| Marianis Driver Services Ltd | Transport & logistics | 2020 |
| Marimag Ltd | Transport & logistics | 2015 |
| Marine Clearance Tech Ltd | Water & waste | 2025 |
| Mario AM Trans Ltd | Transport & logistics | 2014 |
| Mario Speed Trans Limited | Transport & logistics | 2015 |
| Mario Transport Express Ltd | Transport & logistics | 2025 |
| Marion Trans Ltd | Transport & logistics | 2021 |
| Mariostrans Ltd | Transport & logistics | 2015 |
| Marius Firu Limited | Transport & logistics | 2016 |
| Marius S Auto Ltd | Transport & logistics | 2020 |
| Marius Ursu Transport Limited | Transport & logistics | 2017 |
| Mariusadi Ltd | Transport & logistics | 2018 |
| Mariush Limited | Transport & logistics | 2025 |
| Mariusz Kapi Transport Ltd | Transport & logistics | 2024 |
| Mark Andrews Property Services Ltd | Real estate | 2000 |
| Mark Forth Independent Funeral Services Ltd | Other services | 2015 |
| Mark Goddard Transport Ltd | Transport & logistics | 2009 |
| Mark Pick Transport Ltd | Transport & logistics | 2017 |
| Mark's Dairy Limited | Wholesale & retail | 2004 |
| Marketing Bridge Strategic Communications Limited | Professional & scientific | 2009 |
| Markham Langley Millard Ltd | Professional & scientific | 2022 |
| Mars K9 Security Ltd | Administrative & support | 2023 |
| Marshalls (Donington) Limited | Agriculture & fishing | 2002 |
| Marter Trans Ltd | Transport & logistics | 2018 |
| Martin Sharman Home Improvements Ltd | Construction | 2019 |
| Martins of Holbeach Limited | Other services | 2018 |
| Martintas Ltd | Transport & logistics | 2024 |
| Martston Ltd | Manufacturing | 2018 |
| Marurs Ltd | Transport & logistics | 2016 |
| Marwo Ltd | Transport & logistics | 2019 |
| Masaru Ltd | Transport & logistics | 2022 |
| Mason Brothers Cold Storage and Grading Services Limited | Transport & logistics | 2003 |
| Mason Brothers Transport and Warehousing Ltd | Transport & logistics | 2026 |
| Mason Brothers Transport Limited | Transport & logistics | 1985 |
| Mason Productions Ltd | Professional & scientific | 2021 |
| Mass Skip Hire Ltd | Water & waste | 2017 |
| Master Park Homes Ltd | Construction | 2025 |
| Matas Consultancy Limited | Administrative & support | 2023 |
| Matgra Transport Ltd | Transport & logistics | 2018 |
| Mathy Trans Ltd | Wholesale & retail | 2019 |
| Matickas Ltd | Other services | 2017 |
| Matitrans Ltd | Transport & logistics | 2026 |
| Matmore Motor Parts Ltd | Wholesale & retail | 2012 |
| Maven Professionals Limited | Professional & scientific | 2017 |
| Mavrik Holdings Ltd | Financial services | 2023 |
| MAX Attack Trading Limited | Arts & recreation | 2023 |
| MAX Labour Limited | Administrative & support | 2014 |
| Maxey Lawn Care Limited | Agriculture & fishing | 2017 |
| Maxoncards Ltd | Wholesale & retail | 2025 |
| MAY the Forks BE With YOU Limited | Hospitality | 2024 |
| Maysem Limited | Real estate | 2017 |
| Maytree Projects (1120) Ltd | Construction | 2020 |
| Mazurek Ltd | Transport & logistics | 2018 |
| Mazuria Ltd | Transport & logistics | 2022 |
| MB Cleaning Services Spalding Ltd | Administrative & support | 2025 |
| MB Private Hire Ltd | Transport & logistics | 2023 |
| MBL Accounting Limited | Professional & scientific | 2016 |
| Mbs-Expert Ltd | Professional & scientific | 2020 |
| MC Bill Haulage Ltd | Transport & logistics | 2022 |
| MC Gowan Services Nationwide Ltd | Construction | 2021 |
| MC Ring Services Ltd | Construction | 2026 |
| Mcgowan Services (Manchester) Ltd | Construction | 2017 |
| Mcloughlin Way Management Company Ltd | Real estate | 2020 |
| MCM Services Inc Ltd | Manufacturing | 2012 |
| MD3P Property Limited | Real estate | 2021 |
| Mddk Ltd | Transport & logistics | 2018 |
| MDG Plastering Ltd | Construction | 2022 |
| MDN Engineering Services Ltd | Construction | 2018 |
| ME Attend Ltd | Information & communication | 2021 |
| Meadows Driver Services Ltd | Transport & logistics | 2011 |
| Meadstone Construct UK Limited | Professional & scientific | 2009 |
| Mechanical,Repair and Maintenance Electrical Services Ltd | Manufacturing | 2020 |