| Mission Restaurant Co Ltd | Hospitality | 2020 |
| Missy Fast Services Ltd | Wholesale & retail | 2025 |
| Mistramark Limited | Arts & recreation | 1985 |
| Miswa Chemicals Limited | Manufacturing | 1981 |
| MIT Northampton Limited | Transport & logistics | 2014 |
| Mitch Jenkins Limited | Professional & scientific | 2006 |
| Mitchell Property Developments & Land Ltd | Construction | 2022 |
| Mitchell Retail Ltd | Administrative & support | 2016 |
| Mitchell Tax Services Ltd | Professional & scientific | 2019 |
| Mitchell-Armstrong Limited | Education | 2015 |
| Mitransport Ltd | Transport & logistics | 2013 |
| MIV Spedition Ltd | Transport & logistics | 2026 |
| Mivaan Estates Ltd | Real estate | 2025 |
| Mizinna Services Ltd | Wholesale & retail | 2020 |
| Mizralegal Ltd | Professional & scientific | 2023 |
| MJ & KK Trans Ltd | Transport & logistics | 2015 |
| MJ ABC Contractors Ltd | Construction | 2022 |
| MJ Allure Ltd | Other services | 2022 |
| MJ Protection Specilist Ltd | Professional & scientific | 2026 |
| MJ Reillys Industrial Roofing & Cladding Ltd | Construction | 2023 |
| MJ SAJ Composites Ltd | Manufacturing | 2018 |
| MJB Company Services Limited | Professional & scientific | 2003 |
| MJB System Solutions Ltd | Information & communication | 2025 |
| MJD SPV Limited | Real estate | 2024 |
| MJH Surveying Services Ltd | Construction | 2019 |
| MJK 4PROPERTIES Limited | Households | 2022 |
| MJL Limited | Construction | 2000 |
| Mjlock Consultancy Ltd | Real estate | 2025 |
| MJO Haulage Ltd | Transport & logistics | 2019 |
| Mjp@Designs Ltd | Professional & scientific | 2024 |
| MJS Mediation Limited | Other services | 2018 |
| MJS Property Consultancy Limited | Real estate | 2008 |
| MJW Goods and Supply Ltd | Wholesale & retail | 2026 |
| MJW Healthcare Solutions Ltd | Professional & scientific | 2025 |
| MJW Real Estate Solutions Ltd | Real estate | 2026 |
| MK Assets Ltd | Construction | 2014 |
| MK City Lettings Limited | Real estate | 2019 |
| MK Dance Theatre CIC | Education | 2022 |
| MK Delivery Services Ltd | Transport & logistics | 2020 |
| MK Drainage and Environmental Limited | Water & waste | 2019 |
| MK Electrical and Testing Ltd | Construction | 2022 |
| MK Finance Group Ltd | Financial services | 2007 |
| MK Gemini Ltd | Administrative & support | 2020 |
| MK Haulage Ltd | Transport & logistics | 2024 |
| MK Interpreter Limited | Professional & scientific | 2018 |
| MK London Vista Investments Ltd | Real estate | 2019 |
| MK Precision Engineering Limited | Manufacturing | 2011 |
| MK Top Construction Ltd | Construction | 2021 |
| MK Vista Limited | Professional & scientific | 2007 |
| MKB Buildings Ltd | Real estate | 2024 |
| Mkcosmopolitanfashion Ltd | Wholesale & retail | 2023 |
| MKH Northampton Ltd | Hospitality | 2025 |
| MKH Property Maintenance Ltd | Construction | 2026 |
| MKN Trans Logistics Ltd | Transport & logistics | 2025 |
| MKP Management (London) Ltd | Professional & scientific | 2019 |
| MKP Trans Ltd | Transport & logistics | 2025 |
| MKT Group Ltd | Other services | 2012 |
| ML Paint & Body Ltd | Wholesale & retail | 2024 |
| ML Trust & Estate Planning Company LLP | | 2010 |
| Mlation Ltd | Real estate | 2018 |
| MLC (Car Parks) Limited | Real estate | 2011 |
| MLE Groundworks&Surfacing Limited | Administrative & support | 2014 |
| Mlgc Holdings Limited | Real estate | 2024 |
| MLJ Group Limited | Hospitality | 2017 |
| MLM Trade Limited | Wholesale & retail | 2025 |
| MLS Solutions Ltd | Manufacturing | 1996 |
| Mlwt Investment Ltd | Real estate | 2025 |
| MM Electrical & Renewables Limited | Construction | 2025 |
| MM Logistix Ltd | Transport & logistics | 2023 |
| MM Network Solutions Ltd | Professional & scientific | 2024 |
| MM Property Investments Group Ltd | Real estate | 2026 |
| Mm&Kk Transport Ltd | Transport & logistics | 2021 |
| MM1 Property Ltd | Real estate | 2021 |
| MM6 Consulting Ltd | Professional & scientific | 2025 |
| MMA Grounds Maintenance Ltd | Administrative & support | 2025 |
| MMA TV App Ltd | Information & communication | 2019 |
| MMA TV Ltd | Information & communication | 2015 |
| Mmas Trnas Ltd | Transport & logistics | 2026 |
| Mmcbuild Limited | Construction | 2022 |
| MMD Delivery Ltd | Transport & logistics | 2025 |
| MMG Financial Management Holdings Limited | Financial services | 2021 |
| MMG Financial Management Limited | Financial services | 2003 |
| MMI Spedition Ltd | Transport & logistics | 2019 |
| Mmia Limited | Financial services | 2017 |
| MMK Surfacing Limited | Construction | 2018 |
| Mmkey Ltd | Real estate | 2024 |
| MML Transport Ltd | Transport & logistics | 2020 |
| MMP Project Management Services Limited | Professional & scientific | 2007 |
| Mmph Properties Ltd | Real estate | 2018 |
| Mmpz Properties Ltd | Real estate | 2025 |
| MMR Rallysport Limited | Arts & recreation | 2017 |
| Mmsj Holdings Limited | Real estate | 2004 |
| MMT Cargo Limited | Transport & logistics | 2026 |
| MN Space Consulting Limited | Professional & scientific | 2023 |
| MNC Stribbons UK Ltd | Manufacturing | 2012 |
| Mnerie Limited | Administrative & support | 2016 |
| MNK Retail Ltd | Wholesale & retail | 2024 |
| MO Auto Performance Ltd | Wholesale & retail | 2019 |
| MO Express Ltd | Other services | 2024 |
| MO Group Logistics Limited | Transport & logistics | 2024 |