| MIR Traders Ltd | Wholesale & retail | 2019 |
| Miraval Residential Ltd | Real estate | 2020 |
| Mirrorbox Studios Limited | Professional & scientific | 2011 |
| Mirtescu Ltd | Transport & logistics | 2023 |
| Mirumeh Ltd | Real estate | 2024 |
| Mirzescu Pro Construction Ltd | Construction | 2025 |
| Mish Marques Holdings Limited | Real estate | 2025 |
| Misha Enterprise Ltd | Wholesale & retail | 2024 |
| Mishi Finds Ltd | Wholesale & retail | 2025 |
| Miso Hungry Ltd | Hospitality | 2025 |
| Miss Hampshire Ltd | Arts & recreation | 2025 |
| Miss Pet Ltd | Wholesale & retail | 2020 |
| Miss Pita Limited | Hospitality | 2025 |
| Mission Beard Grooming Co. Ltd | Wholesale & retail | 2018 |
| Mission Tailors Ltd | Manufacturing | 2017 |
| Mist Projects Ltd | Construction | 2018 |
| Mister Beef Ltd | Hospitality | 2023 |
| Mister Master and Little Miss Ltd | Other services | 2013 |
| Mistletoe Finance Limited | Financial services | 2017 |
| Mistletoe Holdings Limited | Financial services | 2017 |
| Mistletoe Investments Limited | Financial services | 2021 |
| Mistral Estates Ltd | Real estate | 2010 |
| Mistral Renewable Energy Ltd. | Energy | 2014 |
| Mistrz Limited | Construction | 2017 |
| Misty Racing Limited | Wholesale & retail | 2017 |
| Misty Wealth Limited | Financial services | 2011 |
| MIT Developments Ltd | Real estate | 2021 |
| Mitch Limited | Professional & scientific | 2023 |
| Mitchell and SON Additive Manufacturing Ltd | Manufacturing | 2019 |
| Mitchell Automotive Solutions Limited | Wholesale & retail | 2019 |
| Mitchell Brickwork Limited | Construction | 2021 |
| Mitchell Heritage Ltd | Professional & scientific | 2019 |
| Mitchells (Millbrook) Limited | Wholesale & retail | 1947 |
| Mitchells Construction Ltd | Construction | 2023 |
| Mitech Interiors Limited | Construction | 2001 |
| Mithmill Ltd | Information & communication | 2024 |
| MITHY55 Limited | Health & social care | 2022 |
| Mitigate Ltd | Wholesale & retail | 2020 |
| Mitoob Limited | Transport & logistics | 2020 |
| MIU Trans Ltd | Transport & logistics | 2017 |
| Mixolydian Publications Limited | Professional & scientific | 2012 |
| Miya Hair Limited | Wholesale & retail | 2017 |
| Mizen Build Limited | Construction | 2014 |
| MJ Building & Groundworks Ltd | Construction | 2022 |
| MJ Construction & Developments Ltd | Construction | 2019 |
| MJ Lewis Consulting Limited | Professional & scientific | 2022 |
| MJ Services (GB) Limited | Professional & scientific | 2004 |
| MJ South Ltd | Transport & logistics | 2013 |
| MJ Travel Limited | Transport & logistics | 2019 |
| Mj's Kebab House Limited | Hospitality | 2024 |
| MJA Electrical and Maintenance Ltd | Construction | 2026 |
| Mjag Consulting Limited | Information & communication | 2017 |
| Mjag Homes Limited | Real estate | 2020 |
| Mjassi Logistics Limited | Transport & logistics | 2026 |
| Mjay Elite Group Ltd | Wholesale & retail | 2026 |
| MJB Fleet Maintenance Ltd | Manufacturing | 2025 |
| MJB South Limited | Other services | 2023 |
| MJC Builders & Decorators Limited | Construction | 2008 |
| MJC Tree Services Limited | Agriculture & fishing | 2001 |
| Mjcarsolution Ltd | Wholesale & retail | 2022 |
| Mjcsmotors Limited | Wholesale & retail | 2025 |
| MJD Metalcraft Limited | Manufacturing | 2004 |
| MJD Motion Ltd | Transport & logistics | 2025 |
| MJH Hypa Advisors Limited | Financial services | 2025 |
| MJH Transport Ltd | Transport & logistics | 2021 |
| MJL Blasting & Painting Ltd | Construction | 2018 |
| MJL Decorating Services Ltd | Construction | 2016 |
| MJM Cars Limited | Wholesale & retail | 2018 |
| MJP Capital Ltd | Real estate | 2025 |
| MJP Carpentry Ltd | Construction | 2015 |
| MJS Construction Group Ltd | Construction | 2013 |
| MJS Electrical Services Ltd | Construction | 2025 |
| MJS School Improvement Consulting Limited | Extraterritorial | 2023 |
| MJS Shipping and Transport Ltd | Transport & logistics | 2008 |
| MJS Website Design Ltd | Information & communication | 2013 |
| MJT Proservices Ltd | Construction | 2017 |
| MK Chiro Ltd | Health & social care | 2017 |
| MK Eden Properties Ltd | Real estate | 2021 |
| MK Electrics (South) Ltd | Construction | 2025 |
| MK Fitness Coaching Ltd | Arts & recreation | 2025 |
| MK Samuels Electrical Contractors Limited | Construction | 2006 |
| MK Triangle Barbers Limited | Other services | 2023 |
| MK UK Projects UK Limited | Construction | 2024 |
| Mk-Joe Ltd | Administrative & support | 2019 |
| MKB Marine Electrics Limited | Manufacturing | 2023 |
| MKD (Southampton) Limited | Hospitality | 2017 |
| MKD Conservation, Construction & Restoration Limited | Construction | 2017 |
| MKD Software & Consultancy Ltd | Information & communication | 2019 |
| MKE Distributions Ltd | Wholesale & retail | 2026 |
| MKF Trading Ltd | Wholesale & retail | 2024 |
| Mkfly Limited | Transport & logistics | 2025 |
| MKG Property Holdings Limited | Construction | 2017 |
| MKG Southampton Ltd | Arts & recreation | 2017 |
| MKI Courier Ltd | Transport & logistics | 2024 |
| MKJ Smith Property Ltd | Construction | 2019 |
| MKL Logistics Limited | Transport & logistics | 2018 |
| Mkmc Investments Ltd | Information & communication | 2019 |
| Mksa Cleaning Services Ltd | Administrative & support | 2019 |
| ML Carpets & Flooring Limited | Wholesale & retail | 2004 |
| ML Masts and Rigging Ltd | Manufacturing | 2024 |