| Macclesfield Packed Products Limited | Manufacturing | 2016 |
| Mach Ice Cleaning Limited | Administrative & support | 2018 |
| Machine Embroidery Supplies Ltd | Wholesale & retail | 2020 |
| Machx Machinery Ltd | Wholesale & retail | 2026 |
| Mack BD Ltd | Construction | 2009 |
| Mackay Medical Consult Ltd | Health & social care | 2024 |
| Mackol Trans Ltd | Transport & logistics | 2021 |
| Macoy Limited | Construction | 2024 |
| Macrae Perry Business Development & Transformation Ltd | Professional & scientific | 2026 |
| Macrideout Ltd | Transport & logistics | 2018 |
| Macsteelworks&Security Limited | Manufacturing | 2025 |
| Macuri Ltd | Construction | 2020 |
| Macwilliam Ltd | Real estate | 2019 |
| Macy ( Doncaster ) Limited | Other services | 2010 |
| MAD Blue Ltd | Wholesale & retail | 2024 |
| MAD Contracts Ltd | Construction | 2005 |
| MAD Friday Productions Ltd | Information & communication | 2021 |
| Madalen Ltd | Wholesale & retail | 2015 |
| Madd XP Ltd | Information & communication | 2025 |
| Madder Lake Ltd | Professional & scientific | 2023 |
| Maddison Parry TM Ltd | Public administration | 2024 |
| Maddison Projects Ltd | Professional & scientific | 2026 |
| Maddison Property Ltd | Real estate | 2022 |
| Made Secure Limited | Information & communication | 2026 |
| Made to Market Ltd | Professional & scientific | 2022 |
| MADE2 Developments Limited | Households | 2017 |
| Madej Transport Service Ltd | Transport & logistics | 2023 |
| Madio Ltd | Transport & logistics | 2024 |
| Mado Trans Ltd | Transport & logistics | 2017 |
| Madre Perla Limited | Hospitality | 2024 |
| Mae's of Barnby DUN Ltd | Wholesale & retail | 2021 |
| Maestro Removals Ltd | Transport & logistics | 2013 |
| MAF Commercial Ltd | Financial services | 2016 |
| MAF Drivers Ltd | Construction | 2017 |
| MAF Spedition Ltd | Transport & logistics | 2025 |
| Mafiss Limited | Professional & scientific | 2012 |
| Mafson Ltd | Wholesale & retail | 2020 |
| MAG Property Developments Limited | Real estate | 2023 |
| MAG Sports Limited | Arts & recreation | 2023 |
| Magd Holdings Limited | Real estate | 2017 |
| Magen & Kadima Ltd | Wholesale & retail | 2024 |
| Magenta Signs Ltd | Professional & scientific | 2020 |
| Maggot Operations Limited | Information & communication | 2010 |
| Magic Cover Ltd | Financial services | 2025 |
| Magic Crafting Limited | Manufacturing | 2020 |
| Magic Home Services Ltd | Extraterritorial | 2020 |
| Magicka.Ai Ltd | Information & communication | 2025 |
| Magill Commercial Properties Limited | Real estate | 2020 |
| Magill Group Limited | Financial services | 2025 |
| Magill Marketing & Management Limited | Administrative & support | 2020 |
| Magill Painting Contractors Limited | Construction | 2003 |
| Magill Residential Properties Limited | Real estate | 2020 |
| Magnetic Sight LP | | 2022 |
| Magnolia Trading Company Limited | Wholesale & retail | 2020 |
| Magpies Properties Limited | Real estate | 2022 |
| Mags Group Limited | Financial services | 2023 |
| Magtom Transport Ltd | Transport & logistics | 2021 |
| Mahal Healthcare Limited | Health & social care | 2018 |
| Mahh Estates Ltd | Real estate | 2024 |
| Mahon Glazing & Exteriors Ltd | Construction | 2026 |
| MAI Spedition Ltd | Transport & logistics | 2021 |
| Maia-Logistic Ltd | Transport & logistics | 2019 |
| Maicare Ltd | Administrative & support | 2018 |
| Maidstone Law Limited | Other services | 2018 |
| Main Street Food Limited | Hospitality | 2017 |
| Maine Coon Silver Paws Ltd | Agriculture & fishing | 2024 |
| Maini & Sons Holdings Limited | Real estate | 2025 |
| Maintenance Plumbing and GAS Ltd | Construction | 2016 |
| Maison Bidco Limited | Real estate | 2021 |
| Maison Finco PLC | Financial services | 2021 |
| Maja JS Trans Ltd | Transport & logistics | 2024 |
| Majestic Machinery Hire Limited | Administrative & support | 2025 |
| Majestic Polymers Ltd | Administrative & support | 2018 |
| Majestix Car Sales Ltd | Wholesale & retail | 2024 |
| Majesty Vintage Club Limited | Wholesale & retail | 2024 |
| Majorchem Limited | Manufacturing | 2026 |
| MAK Country Estates Limited | Arts & recreation | 2016 |
| MAK Distribution Limited | Wholesale & retail | 2009 |
| MAK Medical Services Ltd | Health & social care | 2014 |
| MAK Products Limited | Wholesale & retail | 2025 |
| MAK Trading Group Limited | Other services | 2016 |
| Make a Difference Education Limited | Education | 2017 |
| Make a Difference Provision Ltd | Education | 2023 |
| Make a LEG Ltd | Manufacturing | 2019 |
| Make Homes (North) Ltd | Construction | 2024 |
| Make IT Bright Cleaning Solutions Ltd | Administrative & support | 2025 |
| Make IT Wild (Holdings) Limited | Real estate | 2018 |
| Make IT Wild Limited | Arts & recreation | 2017 |
| MAKEITWORK4ME Limited | Information & communication | 2025 |
| MAL Plant Services Limited | Manufacturing | 2020 |
| Malaaha Style Ltd | Wholesale & retail | 2025 |
| Malawei Ltd | Health & social care | 2021 |
| Malbora Properties Ltd | Real estate | 2025 |
| Malcolm C. FOY & Co Limited | Professional & scientific | 2012 |
| Mald Commercials Limited | Wholesale & retail | 2024 |
| Maleic Engineering Ltd | Professional & scientific | 2006 |
| Mali's 44 Ltd | Other services | 2025 |
| Mali-Uk Bilateral Business Forum Ltd | Other services | 2025 |
| Malik Cargo Ltd | Transport & logistics | 2026 |
| Malkins Independent Traders Ltd | Real estate | 2025 |