| MAX IR Ltd | Transport & logistics | 2025 |
| MAX Marshall Racing Ltd | Wholesale & retail | 2017 |
| MAX Valeting Ltd | Other services | 2017 |
| MAX Velocity Limited | Administrative & support | 2015 |
| MAX Vision Courier Service Ltd | Transport & logistics | 2021 |
| Max'Em NIM Ltd | Health & social care | 2013 |
| Max'Em NIM Properties Ltd | Real estate | 2019 |
| Max-Mar Installations Limited | Construction | 2024 |
| MAX. TS Ltd | Transport & logistics | 2018 |
| Maxana Ltd | Professional & scientific | 2016 |
| Maxhdtransport Ltd | Transport & logistics | 2019 |
| Maxherz Limited | Real estate | 2016 |
| Maxikids Limited | Wholesale & retail | 2026 |
| Maxima Drive Limited | Information & communication | 2013 |
| Maximciuc Construction Ltd | Construction | 2025 |
| Maximum Profit Growth Limited | Administrative & support | 2014 |
| Maximus Cleaning Company Ltd | Administrative & support | 1993 |
| Maximus R Properties Ltd | Real estate | 2018 |
| Maxpro Decorating Ltd | Construction | 2015 |
| Maxtri Ltd | Construction | 2025 |
| Maxwell Tipper Hire Ltd | Transport & logistics | 2014 |
| Maxxxa Transport Limited | Transport & logistics | 2019 |
| MAY & Co. Inns Limited | Hospitality | 2025 |
| MAY Beauty London Limited | Other services | 2017 |
| MAY I Help Ltd | Health & social care | 2023 |
| MAY Lettings Ltd | Real estate | 2017 |
| Maya Logistics Ltd | Transport & logistics | 2024 |
| Maya Restaurant Shisha & Cocktail Bar Ltd | Hospitality | 2024 |
| Maya Sparkle & Style Ltd | Construction | 2024 |
| Maya Spedition Limited | Transport & logistics | 2020 |
| Maya World Limited | Manufacturing | 2019 |
| Mayabode Ltd | Real estate | 2025 |
| Maydo Properties Limited | Real estate | 2025 |
| Mayems Limited | Construction | 2006 |
| Mayfair Decorating Ltd | Construction | 2024 |
| Mayfair Meeting Rooms Limited | Administrative & support | 2016 |
| Mayfield Brands Limited | Manufacturing | 2026 |
| Mayfield Consultancy Ltd | Professional & scientific | 2018 |
| Mayfield Residential Ltd | Real estate | 2025 |
| Mayfit Limited | Health & social care | 2014 |
| Mayfourth Holdings Limited | Energy | 2016 |
| Mayhew Chemicals Limited | Wholesale & retail | 2015 |
| Mayleigh House Holdings Ltd. | Professional & scientific | 2001 |
| Mayleigh House Investments Limited | Construction | 2012 |
| Mayline Glass Limited | | 1965 |
| Maynard Collection Ltd | Professional & scientific | 2026 |
| Maynard Regulatory Consultancy Limited | Professional & scientific | 2022 |
| Mayor Tech Limited | Information & communication | 2018 |
| Mayor's Lincs Ltd | Transport & logistics | 2025 |
| Maypoint Consulting Limited | Information & communication | 2026 |
| Mayra Construction Limited | Transport & logistics | 2025 |
| MAZ Retail Ltd | Wholesale & retail | 2025 |
| Maza Transport Ltd | Transport & logistics | 2017 |
| Mazar Properties Ltd | Households | 2026 |
| Maze Inns Limited | Real estate | 2006 |
| Mazilu Limited | Transport & logistics | 2015 |
| MB Domestic Services Ltd | Other services | 2016 |
| MB Network Limited | Administrative & support | 2015 |
| MB Pro Electrical Limited | Construction | 2025 |
| MB Quantity Surveying Ltd | Professional & scientific | 2025 |
| MB Recruitment Solutions Limited | Administrative & support | 2025 |
| MB Tech Services Ltd | Information & communication | 2024 |
| MB UK Services Ltd | Financial services | 2017 |
| MB Utility Consultants Ltd | Professional & scientific | 2026 |
| MBA Motors Ltd | Wholesale & retail | 2009 |
| MBA Transport Ltd | Transport & logistics | 2021 |
| MBB Limited | Wholesale & retail | 2024 |
| Mbdin Accountancy Services Limited | Professional & scientific | 2025 |
| MBE Time to Sleep Ltd | Wholesale & retail | 2025 |
| MBH Construction Ltd | Construction | 2001 |
| MBH Corporation PLC | Financial services | 2016 |
| Mbhg Property Management Ltd | Real estate | 2025 |
| MBI Armor Limited | Construction | 2018 |
| MBI Sandycroft Limited | Real estate | 2014 |
| MBM Civil Engineering Ltd | Construction | 2018 |
| MBP Drainage Services Ltd | Construction | 2026 |
| MBR Solutions Limited | Professional & scientific | 1999 |
| Mbsol Ltd | Information & communication | 2020 |
| MBV Transport Ltd | Transport & logistics | 2023 |
| MC & NS Properties Limited | Real estate | 2003 |
| MC Consultancy (2016) Ltd | Administrative & support | 2017 |
| MC Decorators Limited | Professional & scientific | 2012 |
| MC Finex Ltd | Transport & logistics | 2021 |
| MC Loughlin Wood Property Ltd | Real estate | 2022 |
| MC Pro Services Ltd | Construction | 2025 |
| MC UK Electrical Ltd | Construction | 2023 |
| Mc-Edith Angels Health Care Limited | Health & social care | 2020 |
| Mc-Marvcaela Ltd | Wholesale & retail | 2015 |
| Mc-Property Ltd | Real estate | 2022 |
| Mc-Vinit Nameless Group Limited | Wholesale & retail | 2025 |
| MCA Beauty & Clinic Ltd | Health & social care | 2015 |
| Mcauliffe Marketing Limited | Professional & scientific | 2006 |
| Mcbil &Partners Ltd | Real estate | 2023 |
| Mcbt Ltd | Wholesale & retail | 2025 |
| Mccaero Ltd | Construction | 2014 |
| Mccarthy Environmental Limited | Energy | 2007 |
| Mccarthy Hire Limited | Administrative & support | 2025 |
| Mccauley Developments Ltd | Real estate | 2025 |
| Mcclean Holdings Limited | Financial services | 2024 |
| Mcconnel Crescent Management Company Ltd | Households | 2018 |