| Malpas Trading Limited | Real estate | 2015 |
| Managed Connect Ltd | Financial services | 2014 |
| Mango Design Limited | Information & communication | 2010 |
| Mangrove Holdings Ltd | Financial services | 2022 |
| Manor House Builders Limited | Construction | 2000 |
| Maqu Limited | Professional & scientific | 2011 |
| Marathon Automation Limited | Professional & scientific | 2023 |
| Marbreja Ltd | Real estate | 2024 |
| Maredu Partnership Ltd | Information & communication | 2025 |
| Margaret Hills Limited | Wholesale & retail | 1989 |
| Mariko Property Limited | Real estate | 2023 |
| Mark 6 Limited | Professional & scientific | 2000 |
| Mark Derkacz Dotcom Limited | Information & communication | 2011 |
| Mark Henstone Limited | Other services | 2002 |
| Mark Richards PR Consultancy Limited | Administrative & support | 2013 |
| Marleys Bike Shop Limited | Wholesale & retail | 2009 |
| Marmalade & Sons Limited | Financial services | 2020 |
| Marris Consulting Limited | Professional & scientific | 2026 |
| Marshall Hamilton Ltd | Financial services | 2022 |
| Marston Hotels Limited | Hospitality | 1990 |
| Martin Property Investment Company Limited | Real estate | 2022 |
| Martin Smart Design Limited | Professional & scientific | 2021 |
| Massey Ferguson Works Pension Trust Limited | Professional & scientific | 1994 |
| Massive Space Limited | Wholesale & retail | 2018 |
| Matt Jones Colour Ltd | Information & communication | 2026 |
| Maven Patterns Ltd | Professional & scientific | 2018 |
| Mavi Gates Limited | Real estate | 2024 |
| MAX Media Limited | Information & communication | 2024 |
| Maxb Trade Ltd | Wholesale & retail | 2026 |
| Maxjoy International Container Limited | Administrative & support | 2020 |
| Maxwin Optek Co., Ltd | Extraterritorial | 2018 |
| Maychild Limited | Real estate | 2012 |
| Mbse Training and Consulting Limited | Professional & scientific | 2015 |
| MCG Perio Ltd | Health & social care | 2015 |
| Mcmay Property Holdings Ltd | Real estate | 2022 |
| MCS Corporate Strategies Limited | Professional & scientific | 2012 |
| MCV Automotive Refinishing Limited | Manufacturing | 2020 |
| Mead Works Limited | Professional & scientific | 2026 |
| Mecam Accounting Services Limited | Professional & scientific | 2013 |
| Mecca Co., Limited | Wholesale & retail | 2023 |
| Med-Space Ltd | Health & social care | 2024 |
| Medicalsec Services Limited | Administrative & support | 2017 |
| Medina Properties Limited | Real estate | 2017 |
| Meersbrook Therapy Ltd | Professional & scientific | 2019 |
| Mehndi FIX Ltd | Manufacturing | 2020 |
| Meia Noite Ltd | Information & communication | 2021 |
| Meihong Shipping Agency Co., Ltd | Administrative & support | 2023 |
| Melaandme Co., Ltd | Administrative & support | 2022 |
| Mellifera Consulting Ltd | Professional & scientific | 2016 |
| Meouw Limited | Professional & scientific | 2016 |
| Merchant Navy Resources Limited | Administrative & support | 2002 |
| Mercia Imports Limited | Wholesale & retail | 2016 |
| Mercurial Dance Limited | Information & communication | 2004 |
| Merica Co., Ltd | Wholesale & retail | 2013 |
| Meriden Cafe Ltd | Hospitality | 2022 |
| Meriden Plumbing & Heating Ltd | Construction | 2019 |
| Merlin Land Planning and Development Ltd | Real estate | 2010 |
| Metabasics Limited | Information & communication | 2012 |
| Metalworking Solutions Ltd | Wholesale & retail | 2001 |
| Meters Technology Company Limited | Administrative & support | 2019 |
| Metrostudio Group Ltd | Extraterritorial | 2017 |
| Meyond Industrial Co., Ltd. | Extraterritorial | 2020 |
| MG Electric Pacific Limited | Administrative & support | 2021 |
| MGD Property Portfolio Ltd | Real estate | 2021 |
| MGK Window Design Ltd | Construction | 2020 |
| MHC Dispensary Ltd | Professional & scientific | 2021 |
| MHE Training Solutions Ltd | Other services | 2026 |
| Michael F Jones Associates Limited | Professional & scientific | 2005 |
| Michael James Ventures Limited | Professional & scientific | 2014 |
| Michael Rigby Associates Limited | Professional & scientific | 2002 |
| Michelham Consulting Limited | Professional & scientific | 2023 |
| Microkenilworth Limited | Extraterritorial | 1979 |
| Micvin Building Material Co., Ltd | Extraterritorial | 2015 |
| Midland Sourcing Solutions Limited | Professional & scientific | 2012 |
| Midlands Flooring Solutions Ltd | Construction | 2014 |
| Mike Hansford Projects Limited | Professional & scientific | 1999 |
| Mike Stroud Limited | Information & communication | 2022 |
| Miles Ahead Consulting Ltd | Professional & scientific | 2023 |
| Mileteam Limited | Hospitality | 1999 |
| Milik Ltd | Extraterritorial | 2011 |
| Mililo Limited | Wholesale & retail | 1999 |
| Mill Bank Mews Management Company Limited | Households | 1990 |
| Millaco Corporate Limited | Manufacturing | 2018 |
| Milverton Red Limited | Professional & scientific | 2012 |
| Mimodata Ltd | Information & communication | 2013 |
| Minglei Industry Co., Ltd. | Extraterritorial | 2018 |
| Mink-Brushes (UK) Limited | Wholesale & retail | 1999 |
| Minshull Farms Holdings Limited | Financial services | 2025 |
| Minshull Farms Limited | Agriculture & fishing | 2021 |
| MIR Segei International Group Ltd | Extraterritorial | 2018 |
| Miracle Microsystem Ltd | Professional & scientific | 2014 |
| Miracle Union(Global) Co., Ltd | Administrative & support | 2022 |
| Mischa Group Limited | Extraterritorial | 2019 |
| Mistral Capital Trading Limited | Other services | 2013 |
| Mitoca Co., Ltd | Administrative & support | 2024 |
| Mitto Ltd | Extraterritorial | 2025 |
| Miuchem Company Limited | Extraterritorial | 2018 |
| Mixfood Biotech Corporation Limited | Extraterritorial | 2024 |
| MK Kenilworth Ltd | Hospitality | 2023 |
| Mmcl Marine Trading Co., Limited | Administrative & support | 2021 |