| Maxwell Supplies Limited | Wholesale & retail | 2016 |
| Maxxed Limited | Arts & recreation | 2021 |
| MAY Red Limited | Professional & scientific | 2018 |
| May's Coffee and Tea Ltd | Hospitality | 2022 |
| May.I Coaching Ltd | Administrative & support | 2024 |
| May.I Properties Ltd | Real estate | 2024 |
| May.I Solutions Ltd | Professional & scientific | 2021 |
| Maya Suite Ltd | Hospitality | 2022 |
| Mayaki Limited | Wholesale & retail | 2026 |
| Maya’S Traders Ltd | Wholesale & retail | 2025 |
| Mayfair Developments Ltd | Extraterritorial | 2004 |
| Mayfair Medical Clinic Ltd | Health & social care | 2021 |
| Mayfair Vehicle Hire Ltd | Administrative & support | 2023 |
| Mayfield Alpacas Animal Park Ltd | Arts & recreation | 2014 |
| Mayfield Alpacas Farm and Animal Sanctuary Limited | Agriculture & fishing | 2024 |
| Mayfield Commercial Properties Limited | Real estate | 2019 |
| Mayfield Electrical Limited | Construction | 1997 |
| Mayfield Estates Holdings Ltd | Real estate | 2025 |
| Mayfield Fitness Ltd | Arts & recreation | 2025 |
| Mayfield Fulwood Limited | Professional & scientific | 1985 |
| Mayfield Heights (Fulwood) Management Company Limited | Households | 1999 |
| Mayfield Management Services Limited | Households | 2003 |
| Mayfield Properties Limited | Real estate | 2016 |
| Mayfield Property Assets LLP | | 2016 |
| Mayfield Residential Properties Limited | Real estate | 2019 |
| Mayfield Student Properties Limited | Real estate | 2019 |
| Mayfield View Property Limited | Hospitality | 1993 |
| Mayfield Yorkshire Limited | Professional & scientific | 2016 |
| Mayfields Holdings Limited | Financial services | 2024 |
| Mayflower Chapeltown Ltd | Hospitality | 2026 |
| Mayflower Engineering Limited | Manufacturing | 2008 |
| Mayflower Technology Limited | Manufacturing | 2022 |
| Mayhouse Ltd | Real estate | 2023 |
| Mayla Advisory Limited | Professional & scientific | 2025 |
| Mayla Holdings Ltd | Financial services | 2024 |
| Mayland Property Ltd | Real estate | 2025 |
| Mayle Hair Ltd | Other services | 2024 |
| Maymed Ltd | Health & social care | 2021 |
| Maynard Lowe Consulting Limited | Health & social care | 2012 |
| Mayplas Limited | Extraterritorial | 1981 |
| Maypole Health Care Limited | Health & social care | 2016 |
| Mays Catering Ltd | Hospitality | 2025 |
| Mays Propco Ltd | Real estate | 2023 |
| Mays Property Limited | Real estate | 2011 |
| Maysons Services Limited | Real estate | 2024 |
| Maytie Capital Ltd | Real estate | 2024 |
| Maze Care Limited | Health & social care | 2026 |
| Mazorca Games Ltd | Information & communication | 2015 |
| MB Bluesky Trustee Limited | Financial services | 2023 |
| MB Educational and Art Supplies Limited | Extraterritorial | 1998 |
| MB Group (UK) Limited | Professional & scientific | 2003 |
| MB Logistics Worldwide Limited | Transport & logistics | 2014 |
| MB Power Solutions Ltd | Construction | 2022 |
| MB Renovations and Electrical Ltd | Real estate | 2023 |
| MB Resin Bound Surfacing Ltd | Construction | 2019 |
| MB Roofing & Building Limited | Construction | 2003 |
| MB Services Car Sales Ltd | Wholesale & retail | 2019 |
| MB Services Yorkshire Limited | Wholesale & retail | 2005 |
| MB Site Solutions Limited | Other services | 2023 |
| MB Tanning & Beauty Ltd | Other services | 2025 |
| MBA Photography & Films Ltd | Professional & scientific | 2021 |
| Mbas Services Ltd | Professional & scientific | 2023 |
| MBE Commercial Services Limited | Construction | 2018 |
| MBE Group Limited | Real estate | 2025 |
| Mbesheff Ltd | Wholesale & retail | 2021 |
| MBF Supplies Limited | Wholesale & retail | 1994 |
| MBI Electrical Limited | Administrative & support | 2007 |
| Mbirdi Ltd | Health & social care | 2026 |
| Mbirotoi Limited | Public administration | 2019 |
| Mbizo Services Ltd | Public administration | 2017 |
| MBM Aquarium Design Ltd | Other services | 2022 |
| MBM Care Solutions Ltd | Hospitality | 2021 |
| MBM Electrical Holdings Limited | Financial services | 2026 |
| MBM Electrical Limited | Construction | 2023 |
| MBM Holdings Limited | Professional & scientific | 1995 |
| MBM Homes Limited | Real estate | 2024 |
| Mboggs Blur Iconics Ltd | Wholesale & retail | 2026 |
| MBP Mechanical Engineering Ltd | Wholesale & retail | 2020 |
| MBS Building and Maintenance Ltd | Construction | 2022 |
| MBS Construction (Mosborough) Limited | Construction | 2003 |
| MBS Workwear Supplies Ltd | Wholesale & retail | 2019 |
| MC Accounting Ltd | Professional & scientific | 2024 |
| MC Sheff Holdings Ltd | Hospitality | 2024 |
| Mcaba Commercial Finance Limited | Financial services | 2015 |
| Mcadoo and Partners Limited | Professional & scientific | 2018 |
| Mcalpine Property Services Limited | Construction | 2008 |
| Mcbain Family Investment Company Ltd | Financial services | 2016 |
| Mcbangbang Ltd | Manufacturing | 2026 |
| Mcbuff Limited | Extraterritorial | 2005 |
| Mccallum Consultant Limited | Administrative & support | 2024 |
| Mccanna Coaching Limited | Professional & scientific | 2021 |
| Mcclure Timber Supplies Limited | Transport & logistics | 1976 |
| Mccracken Consult & Construct Ltd | Construction | 2009 |
| MCE Decorators Ltd | Construction | 1999 |
| Mcelwaine Medical Services Ltd | Health & social care | 2023 |
| MCG Commercial Services Ltd | Administrative & support | 2018 |
| MCG Family Investments Ltd | Financial services | 2025 |
| Mcgilveray's Limited | Hospitality | 2019 |
| Mcgrizzla Ltd | Arts & recreation | 2024 |
| MCH (Dragoon Court Block B) Developments Ltd | Real estate | 2025 |