| M.Service Nottingham Ltd | Wholesale & retail | 2023 |
| M.T. Interiors & SON Limited | Construction | 1997 |
| M.Tuttey Consultants Ltd | Professional & scientific | 2016 |
| M.U.M.I. Ltd | Real estate | 2022 |
| M0CVO Antennas Limited | Extraterritorial | 2021 |
| M1 Engine Reconditioning Ltd | Wholesale & retail | 2025 |
| M1 Facilities Management Limited | Administrative & support | 2017 |
| M1 GB Marketing Ltd | Professional & scientific | 2025 |
| M1 London and Midlands Training Ltd | Education | 2015 |
| M1 Maintenance Services Limited | Construction | 2014 |
| M1 Mobile Tyres Ltd | Wholesale & retail | 2024 |
| M1 Recoveries Ltd | Transport & logistics | 2022 |
| M10 Fitness Ltd | Arts & recreation | 2008 |
| M12 PJ Limited | Hospitality | 2020 |
| M1COURIERS Ltd | Transport & logistics | 2019 |
| M2 Engineering Services Limited | Professional & scientific | 2018 |
| M2 Petroleum Limited | Extraterritorial | 2010 |
| M4G UK Limited | Professional & scientific | 2019 |
| M4NT3LLH3ALTH Ltd | Information & communication | 2026 |
| M800 Limited | Other services | 2016 |
| MA & WA Limited | Real estate | 2023 |
| MA Accounting Solutions Limited | Professional & scientific | 2024 |
| MA Advisory Services Limited | Professional & scientific | 2018 |
| MA Barbecue Express Ltd | Hospitality | 2025 |
| MA Bmill Co Limited | Real estate | 2026 |
| MA Bros UK Limited | Wholesale & retail | 2019 |
| MA Building Services Nottingham Ltd | Construction | 2022 |
| MA Construct Ltd | Manufacturing | 2024 |
| MA Consulting Ventures Ltd | Professional & scientific | 2025 |
| MA Couriers (Notts) Limited | Transport & logistics | 2026 |
| MA Extensions Ltd | Construction | 2024 |
| MA Foods Ltd | Hospitality | 2026 |
| MA Homelets Ltd | Real estate | 2024 |
| MA Homelink Services Ltd | Real estate | 2019 |
| MA Marley Ltd | Financial services | 2025 |
| MA Motors Notts Limited | Wholesale & retail | 2024 |
| MA Notts Tyres Ltd | Wholesale & retail | 2025 |
| MA on Shan Ltd | Real estate | 2022 |
| MA PER Ltd | Construction | 2026 |
| MA Pharma Limited | Wholesale & retail | 2023 |
| Ma'At Property Group Ltd | Real estate | 2026 |
| MA1 Traders Limited | Wholesale & retail | 2020 |
| MAA Electrical Limited | Construction | 2014 |
| Maaghaa Builders Ltd | Households | 2025 |
| MAAK3 Holdings Limited | Financial services | 2025 |
| Maan Overseas Ltd | Wholesale & retail | 2023 |
| Maarrll Ltd | Wholesale & retail | 2022 |
| MAB Solutions Group Ltd | Other services | 2023 |
| Mabcab Limited | Financial services | 2020 |
| Mabcars Ltd | Wholesale & retail | 2024 |
| Mabec PRS Developments Limited | Real estate | 2017 |
| Mabel's African Food Market Ltd | Wholesale & retail | 2025 |
| Maber EOT Limited | Financial services | 2024 |
| Maber Limited | Real estate | 2009 |
| Mable Investments Limited | Real estate | 2018 |
| Mabpax Properties Ltd | Real estate | 2023 |
| MAC Aesthetics & Beauty Ltd | Other services | 2025 |
| MAC Aesthetics Lounge Ltd | Other services | 2020 |
| MAC Atherton Renovation Limited | Construction | 2021 |
| MAC Capital Nominees Limited | Financial services | 2020 |
| MAC Care+ Limited | Health & social care | 2025 |
| MAC Construct Limited | Construction | 2024 |
| MAC Consult Limited | Professional & scientific | 2021 |
| MAC Contracting Nottingham Limited | Construction | 2010 |
| MAC Electrical Solutions Limited | Construction | 2025 |
| MAC Jacobs Ltd | Health & social care | 2026 |
| MAC Plumbing and Heating (Nottingham) Ltd | Construction | 2023 |
| MAC Property DEV Limited | Real estate | 2023 |
| MAC Property Maintenance Limited | Other services | 2014 |
| MAC Tanning Lounge Ltd | Other services | 2025 |
| MAC1 Electrical (Leics) Ltd | Construction | 2014 |
| Macaba Care Ltd | Health & social care | 2025 |
| Macadam Joinery Limited | Construction | 2026 |
| Macademia PVT Ltd | Education | 2024 |
| Macafe Corporate Solutions Global Ltd | Information & communication | 2024 |
| Macallens Ltd | Hospitality | 2020 |
| Macaulay Sinclair Limited | Professional & scientific | 2003 |
| Macaulay Sinclair Living Ltd | Professional & scientific | 2016 |
| Macc Digital Limited | Professional & scientific | 2025 |
| Maccrose Limited | Administrative & support | 2025 |
| Mace Agencies Limited | Wholesale & retail | 2010 |
| Macesport Ltd | Professional & scientific | 2021 |
| Macey Consultants Limited | Information & communication | 1997 |
| Macgregor Recruitment Solutions Ltd | Administrative & support | 2020 |
| Machall Products Limited | Manufacturing | 1979 |
| Machan Consulting Ltd | Professional & scientific | 2005 |
| Machem Ltd | Administrative & support | 2025 |
| Machin & Toplass Limited | Administrative & support | 2003 |
| Machina Software Ltd | Information & communication | 2026 |
| Machines NOT Beans Ltd | Manufacturing | 2022 |
| Macie Plumbing Ltd | Construction | 2024 |
| MACIEJ73 Transport Ltd | Transport & logistics | 2017 |
| Macildowie Associates Limited | Administrative & support | 1997 |
| Mackay and Schnellmann Limited | Extraterritorial | 1959 |
| Mackenzie Taylor Asset Management Limited | Financial services | 2010 |
| Macklot (Shrewsbury) Ltd | Construction | 2021 |
| Macklot Holdings Limited | Real estate | 2021 |
| Macklot Management Limited | Households | 2023 |
| Maclabs Marketing Ltd | Professional & scientific | 2026 |
| Macombe Consultancy Ltd | Professional & scientific | 2025 |