| Mainzworld Foreva CIC | Health & social care | 2021 |
| Maison Michel UK Limited | Wholesale & retail | 2014 |
| Maison Voyant Limited | Wholesale & retail | 2025 |
| Maitry Limited | Wholesale & retail | 2017 |
| Maiva Corporation Limited | Information & communication | 2008 |
| MAJ Builders Limited | Construction | 2025 |
| MAJ Holdings Limited | Financial services | 2022 |
| MAJ Testing Associates Limited | Information & communication | 2015 |
| Maja Estates Limited | Real estate | 2015 |
| Majanes Kitchen Ltd | Hospitality | 2019 |
| Majdelle Limited | Health & social care | 2026 |
| Majdi the Barber Ltd | Other services | 2024 |
| Majestic Community Care Services CIC | Public administration | 2024 |
| Majestic Dance Enterprises Limited | Arts & recreation | 2023 |
| Majestic Minds C.I.C. | Health & social care | 2025 |
| Majid Hatamieh Ltd | Administrative & support | 2024 |
| Majkhalah Ltd | Wholesale & retail | 2025 |
| Majoda Limited | Wholesale & retail | 2022 |
| Major INK Ltd | Arts & recreation | 2026 |
| MAK Backgammon Limited | Transport & logistics | 2022 |
| MAK Creation Ltd | Wholesale & retail | 2021 |
| MAK-3 Investments Limited | Real estate | 2013 |
| Makaino Services Limited | Health & social care | 2018 |
| Makan House Ltd | Hospitality | 2009 |
| Make IT Your Own Ltd | Administrative & support | 2025 |
| Make the Link Limited | Administrative & support | 2017 |
| Makewood Homes Limited | Real estate | 2003 |
| Maki Boom Ltd | Hospitality | 2020 |
| Makky Limited | Wholesale & retail | 2025 |
| Makoma Ltd | Manufacturing | 2023 |
| MAL & NIK Property Ltd | Households | 2021 |
| MAL Catering Ltd | Hospitality | 2025 |
| Malaika Support Services Ltd | Health & social care | 2023 |
| MALAWI24 Ltd | Information & communication | 2024 |
| Malbert Consulting Limited | Information & communication | 2024 |
| Malbros Properties Limited | Real estate | 2019 |
| Malden Renders and Finishes Limited | Construction | 1998 |
| Malhi & Malhi Limited | Wholesale & retail | 2014 |
| Malhi Brothers Limited | Wholesale & retail | 2008 |
| Malhi Dwellings Ltd | Real estate | 2023 |
| Malin Court Residents Management Company Limited | Households | 2004 |
| Malinda Limited | Professional & scientific | 2013 |
| Malkam Ltd | Transport & logistics | 2023 |
| Mallard Court Freehold Company Limited | Households | 2024 |
| Malli Emporium Limited | Wholesale & retail | 2024 |
| Mallory Court Freehold Limited | Households | 2009 |
| Mallory Court Management Company Limited | Households | 2005 |
| Mallow Court (Burpham) Limited | Households | 2002 |
| Mallow Holdings Limited | Administrative & support | 2005 |
| Maloney Maintenance Limited | Construction | 2002 |
| Maltings Park Management Company Limited | Households | 2012 |
| Malu Events Ltd | Hospitality | 2025 |
| Malvern Court Limited | Real estate | 1987 |
| Mama & Bunny Ltd | Wholesale & retail | 2020 |
| Mama Papa Ltd | Wholesale & retail | 2025 |
| Mamadydiana Ltd | Wholesale & retail | 2022 |
| Mamayer Zafran Limited | Hospitality | 2025 |
| Mamiro Ltd | Information & communication | 2012 |
| Managate Limited | Real estate | 2019 |
| Management & Business Consultants (UK) Ltd | Professional & scientific | 2020 |
| Manahill London Ltd | Wholesale & retail | 2020 |
| Manaiabarret Limited | Hospitality | 2021 |
| MANCHOKIMP81 Limited | Health & social care | 2025 |
| Mandap Services Limited | Construction | 2022 |
| Mandu Services Limited | Construction | 2024 |
| Mandy Maker Ltd | Manufacturing | 2018 |
| Mane Property Investments Ltd | Real estate | 2022 |
| Mangal Sagar Limited | Administrative & support | 2016 |
| Mangerplus Ltd | Hospitality | 2021 |
| Mango Drum Ltd | Wholesale & retail | 2023 |
| Mangotree Kids Ltd | Health & social care | 2021 |
| Manhiya Palace Ecommerce UK Ltd | Wholesale & retail | 2025 |
| Manhood From Within CIC | Education | 2024 |
| Mani & Parm Limited | Hospitality | 2012 |
| Mani International Limited | Professional & scientific | 2023 |
| Manie KAY Limited | Health & social care | 2023 |
| Manifest Consulting Ltd | Professional & scientific | 2019 |
| Manifold Marketing Services LLP | | 2022 |
| Maninos Business Limited | Wholesale & retail | 2015 |
| Manip Ltd | Real estate | 2017 |
| Manjiba Limited | Health & social care | 2015 |
| Mankri AKS Ltd | Wholesale & retail | 2008 |
| Manlite Shipping UK Limited | Transport & logistics | 2025 |
| Mann Abbott & Co. Ltd | Professional & scientific | 1995 |
| Mann Original Wood Design Ltd | Manufacturing | 2014 |
| Manna Utilities and Management Ltd | Other services | 2011 |
| Mannat Private Limited | Hospitality | 2025 |
| MANNEDCROWN3 UK Limited | Transport & logistics | 2026 |
| Mannil Ltd | Construction | 2022 |
| Manor Builders London Ltd | Construction | 2017 |
| Manor Farm Brampton Management Company Limited | Households | 2008 |
| Manor House Drycleaners & Launderers Limited | Other services | 2015 |
| Manor Park Residents Company Ltd | Households | 2012 |
| Manorcorp Limited | Real estate | 2002 |
| Manorcroft Estate Management Company Limited | Households | 1986 |
| Manorix Homes Ltd | Real estate | 2025 |
| Manraj Construction Services Ltd | Construction | 2025 |
| Mansa Trade Limited | Wholesale & retail | 2015 |
| Mansell Mctaggart Storrington Limited | Real estate | 2011 |
| Manta Natural Resources Ltd | Administrative & support | 2007 |