| Marcomz Networks Limited | Information & communication | 2006 |
| Marfin Limited | Other services | 2006 |
| Mariella Dawn Budal Ltd | Real estate | 2023 |
| Mark's Village Limited | Hospitality | 2016 |
| Market Street Studio Ltd | Wholesale & retail | 2021 |
| Marketing Buckle Ltd | Professional & scientific | 2025 |
| Martile Limited | Construction | 2021 |
| Maru MAA Limited | Hospitality | 2016 |
| Maruti Properties Investment Limited | Real estate | 2020 |
| Masstec Media Limited | Information & communication | 2019 |
| MAT Transport Ltd | Transport & logistics | 2018 |
| Matchclean Ltd | Administrative & support | 2021 |
| Mates Services Ltd | Construction | 2026 |
| Mathu Trading UK Ltd | Wholesale & retail | 2011 |
| Matt & Nate Limited | Administrative & support | 2012 |
| Mavexa International Limited | Information & communication | 2025 |
| Mawi Construction Ltd | Other services | 2020 |
| MAX Builder Ltd | Construction | 2012 |
| MAX Snack Bar Limited | Hospitality | 2018 |
| Maxi Pizza Limited | Hospitality | 2022 |
| Maxi Taxi Services Ltd | Transport & logistics | 2023 |
| Maximum M K Tradings Ltd | Real estate | 2012 |
| Maxiten Group Limited | Wholesale & retail | 2025 |
| Maxraritytrading Ltd | Wholesale & retail | 2026 |
| Maxwell's Contracting and Consulting Limited | Wholesale & retail | 2024 |
| Mayday Clinics Ltd | Real estate | 2020 |
| Mayday MOT & Service Centre Ltd | Wholesale & retail | 2013 |
| Mayfield Court (Thornton Heath) Limited | Households | 1993 |
| MBC Capital Ltd | Wholesale & retail | 2019 |
| MBO Contracting Limited | Professional & scientific | 2013 |
| Mbsultan Limited | Wholesale & retail | 2025 |
| Mbuilding Ltd | Construction | 2020 |
| Mbvc Property Services Ltd | Real estate | 2020 |
| MC FIX Ltd | Construction | 2018 |
| Mccarthy Painters & Decorators Ltd | Construction | 2024 |
| Mcdac Ltd | Construction | 2024 |
| Mchugh Property Services Ltd | Construction | 2021 |
| Mckat Homes Ltd | Real estate | 2020 |
| Mckat Restaurants PVT Ltd | Hospitality | 2023 |
| MCKENZI3KICKZ CIC | Wholesale & retail | 2025 |
| Mcmillanwoods (UK) Ltd | Professional & scientific | 2020 |
| MD Beauty Flowers Limited | Other services | 2020 |
| Mdskisk Limited | Real estate | 2025 |
| MEC Solutions London Ltd | Construction | 2021 |
| Media Brandz Limited | Wholesale & retail | 2021 |
| Meekl Consultancy Services Ltd | Information & communication | 2021 |
| Meeraki Limited | Wholesale & retail | 2020 |
| Meet Presidential & Palatial Cleaners Ltd | Administrative & support | 2021 |
| Meetoria Homes Limited | Construction | 2026 |
| Megamax Traders Limited | Agriculture & fishing | 2017 |
| Meghet Ltd | Real estate | 2026 |
| Mehdi Foundation International | Health & social care | 2009 |
| MEL1 Services Ltd | Wholesale & retail | 2023 |
| Melanin Tours Limited | Administrative & support | 2025 |
| Melloz Barbers Limited | Other services | 2020 |
| Melnyk Carpentry Ltd | Manufacturing | 2023 |
| Mentivox Ltd | Information & communication | 2026 |
| Mercury Care Services Limited | Hospitality | 2012 |
| Merenise Mian Ltd | Manufacturing | 2025 |
| Mesa Guzman Couriers Limited | Transport & logistics | 2023 |
| Metrodomus Holdings Ltd | Real estate | 2024 |
| Metros Dinamicos UK Ltd | Construction | 2025 |
| Mettle Services CIC | Professional & scientific | 2022 |
| Meyo Traders Limited | Wholesale & retail | 2025 |
| MGC Estates Ltd | Real estate | 2022 |
| MGR UK Services Ltd | Construction | 2019 |
| MH Wholesale Deals Ltd | Wholesale & retail | 2026 |
| MHM Care Solutions Ltd | Financial services | 2025 |
| Michael. J. Services Ltd | Information & communication | 2024 |
| Micronet Communications Limited | Professional & scientific | 1989 |
| Midal Capital Ltd | Information & communication | 2026 |
| MIDO5 Limited | Construction | 2019 |
| Migrants in Action CIC | Professional & scientific | 2023 |
| Mihai Delivery Equipment Limited | Transport & logistics | 2022 |
| Mikeinc Ltd | Administrative & support | 2021 |
| Mikhael Electrical Limited | Construction | 2019 |
| Milan & Play Ltd | Wholesale & retail | 2021 |
| Million Multi Trader Ltd | Wholesale & retail | 2026 |
| Millionz Starz Ltd | Administrative & support | 2019 |
| Mimi Liam Limited Limited | Wholesale & retail | 2019 |
| MIR Business Group Ltd | Real estate | 2020 |
| Miracle Word of Jesus Church | Other services | 2014 |
| Miraya Contractors Limited | Construction | 2023 |
| Mirza Motors Ltd | Wholesale & retail | 2017 |
| Misha Marine Surveyor Ltd | Administrative & support | 2016 |
| Mishwa Food Limited | Information & communication | 2025 |
| Miss Pro Nail Salon Limited | Other services | 2025 |
| Mission Fellowship International | Other services | 2016 |
| Mjsp Ltd | Construction | 2025 |
| MK Agyem Limited | Construction | 2015 |
| MK Foundations Ltd | Real estate | 2023 |
| MK Launderette Limited | Wholesale & retail | 2020 |
| MKA Trading (UK) Ltd | Hospitality | 2011 |
| MKG Consultancy Ltd | Information & communication | 2024 |
| MKR Skaffolding Limited | Construction | 2025 |
| MM Group Services Ltd | Construction | 2023 |
| MM Planning and Architecture Services Ltd | Construction | 2023 |
| MM Shark Limited | Information & communication | 2024 |
| MMK Cleaning Solution Ltd Ltd | Administrative & support | 2023 |
| Mmremoval&Services Ltd | Construction | 2025 |