| Metro Northern Properties Limited | Hospitality | 2016 |
| Metro Property Holdings Limited | Real estate | 2016 |
| Metropolitan Hospitality Ltd | Hospitality | 2014 |
| Mfbauk Limited | Professional & scientific | 2022 |
| MG Velo Limited | Wholesale & retail | 2026 |
| MGR Heating & Plumbing Limited | Construction | 2016 |
| MH Promotions Limited | Professional & scientific | 2015 |
| MHC Building & Design Ltd | Construction | 2024 |
| MHV Glossop Ltd | Real estate | 2025 |
| MI7 Green Energy Projects Ltd | Energy | 2025 |
| Michael Mcdonald Limited | Wholesale & retail | 2006 |
| Midas of Knutsford Limited | Wholesale & retail | 2017 |
| Midland Property Factors Ltd | Hospitality | 2010 |
| Mikar Limited | Real estate | 2022 |
| Mike Whittaker Builders Limited | Construction | 2010 |
| Millbrook Roofing Limited | Construction | 2025 |
| Millpause Limited | Households | 1990 |
| Millpond Court Management Company Ltd | Households | 2021 |
| Millways Property Management Limited | Households | 1982 |
| Mindful Coherence Ltd | Education | 2023 |
| Ministry of Make UP Limited | Wholesale & retail | 2017 |
| Mint (UK) Recruitment Ltd | Other services | 2011 |
| Miss Money Savvy Limited | Information & communication | 2022 |
| Missioncritical HD Ltd | Real estate | 2023 |
| MJG Project Management Limited | Construction | 2008 |
| MJI Group Holdings Limited | Financial services | 2023 |
| MJI Logistics Group Limited | Transport & logistics | 2022 |
| MJI Properties (Over Peover) Ltd | Real estate | 2012 |
| MKF Advisory & Consultants Ltd | Professional & scientific | 2024 |
| MLC Door Services Ltd | Manufacturing | 2013 |
| MLS Property Management Limited | Real estate | 2021 |
| Mlts Holdings Limited | Administrative & support | 2015 |
| MMB Publishing Ltd | Information & communication | 2017 |
| MMD Consultants Ltd | Professional & scientific | 2023 |
| Mobberley Labs Ltd | Information & communication | 2026 |
| Mobberley Station Cattery Ltd | Agriculture & fishing | 2023 |
| Modelstone Limited | Other services | 2003 |
| Modern Unique Developments Limited | Construction | 2014 |
| Mohan & Mansi IT Solutions Ltd | Information & communication | 2016 |
| Monckton Properties (Holdings) Limited | Professional & scientific | 2002 |
| Monckton Properties Limited | Administrative & support | 1960 |
| Monee Holdings Ltd | Administrative & support | 2024 |
| Money Industries Limited | Wholesale & retail | 2014 |
| Moonbeam Bidco Ltd | Financial services | 2021 |
| Moonbeam EBT Limited | Professional & scientific | 2021 |
| Moonbeam Hedgeco 1 Ltd | Financial services | 2021 |
| Moonbeam Hedgeco 2 Ltd | Financial services | 2021 |
| Moonbeam Midco 1 Ltd | Financial services | 2021 |
| Moonbeam Midco 2 Ltd | Financial services | 2021 |
| Moonbeam Topco Ltd | Financial services | 2021 |
| Morgan Edwards Limited | Wholesale & retail | 2018 |
| Morton Baxter Associates Limited | Professional & scientific | 2010 |
| Moss Farm Limited | Hospitality | 2015 |
| Moss Hall Farm Management Company (High Legh) Limited | Households | 2007 |
| Moss Oaks Group Limited | Agriculture & fishing | 2023 |
| Moss Wood Farm Ltd | Wholesale & retail | 2023 |
| Motion-Mount Ltd | Wholesale & retail | 2017 |
| Motorfirst Limited | Wholesale & retail | 2011 |
| Motrix Limited | Wholesale & retail | 2017 |
| Mount Pleasant Holdings (UK) Limited | Construction | 2013 |
| Mount Pleasant Nursing Home Limited | Health & social care | 1996 |
| Moxie 365 Ltd | Wholesale & retail | 2020 |
| MP Healthcare Consulting Ltd | Health & social care | 2023 |
| MPA Consulting Limited | Extraterritorial | 2001 |
| MPH Services Northwest Ltd | Construction | 2024 |
| Mpnh Ltd | Health & social care | 2015 |
| MRB Instrumentation Ltd | Manufacturing | 2023 |
| MSW Freelance Ltd | Information & communication | 2020 |
| MSW Property Ltd | Real estate | 2019 |
| Muntane Limited | Health & social care | 2013 |
| Murano Management UK Limited | Other services | 2023 |
| Murfitt Ltd | Information & communication | 2014 |
| Murmuration Solutions Limited | Other services | 2026 |
| Murphy Advisory Limited | Professional & scientific | 2026 |
| Music Editions Ltd | Information & communication | 2019 |
| Muto 2010 Limited | Professional & scientific | 2009 |
| Muve Live Ltd | Health & social care | 2019 |
| MVT Surveying Consultancy & Training Limited | Professional & scientific | 2012 |
| Mwsi Ltd | Professional & scientific | 2022 |
| My Bounti UK Limited | Wholesale & retail | 2021 |
| Myko International Limited | Manufacturing | 2019 |
| Mylandco Ltd | Professional & scientific | 2025 |
| Myrafikiai Ltd | Information & communication | 2025 |
| Mythentic Limited | Wholesale & retail | 2023 |
| N3 Enterprises Limited | Administrative & support | 2005 |
| Nanare Limited | Real estate | 2021 |
| Nanosafe-Uk Limited | Information & communication | 2021 |
| Narrate for ME Limited | Information & communication | 2024 |
| Nassab Estates Limited | Real estate | 2020 |
| Nassab Group Limited | Financial services | 2023 |
| NAT Property Limited | Real estate | 2021 |
| Natalia Chappell & Co Ltd | Administrative & support | 2024 |
| Nathan Oxendale Mortgages Limited | Financial services | 2022 |
| Nation Assist Ltd | Transport & logistics | 2016 |
| Nationwide Advice Limited | Extraterritorial | 2018 |
| Nature Leaf Limited | Wholesale & retail | 2019 |
| Naybuk Pumps Limited | Manufacturing | 1972 |
| ND6 Ltd | Professional & scientific | 2021 |
| Neocivils Ltd | Construction | 2023 |
| Neon Freight Limited | Transport & logistics | 2012 |