| Mayfair Film Partnership Limited | Professional & scientific | 2009 |
| Mayfair Funding Limited | Administrative & support | 2015 |
| Mayfair Optical Ltd | Health & social care | 2025 |
| Mayfield Imaging Ltd | Health & social care | 2024 |
| Mayfield Park Consulting Ltd | Extraterritorial | 2024 |
| Mayfield Properties (Bristol) Limited | Real estate | 2018 |
| Mayfield Psychiatry Ltd | Health & social care | 2025 |
| Mayfields Homes Limited | Construction | 2019 |
| Mayfly Consulting Limited | Information & communication | 2010 |
| Mayfly Facilities Management Ltd | Professional & scientific | 2025 |
| Mayfly Kitchens Ltd | Construction | 2021 |
| Maygar Limited | Administrative & support | 2018 |
| Mayhead Civils Limited | Real estate | 2020 |
| Mayhouse Consulting Limited | Professional & scientific | 2021 |
| Maynard Windows Ltd | Construction | 2017 |
| Maynards Collective Ltd | Wholesale & retail | 2026 |
| Maynards Mechanical Handling Limited | Manufacturing | 2019 |
| MAYO13 Ltd. | Water & waste | 2022 |
| Maypole Capital Services Ltd | Financial services | 2011 |
| Mayson Ltd | Hospitality | 2020 |
| Maytham Homes Ltd | Real estate | 2025 |
| Maytime Ltd | Professional & scientific | 2026 |
| Maywood Investments Limited | Real estate | 2025 |
| MAZ Plus Ltd | Construction | 2026 |
| MAZ Project Consultants Ltd | Professional & scientific | 2014 |
| Mazaza Cleaning Ltd | Administrative & support | 2025 |
| Maze Clothing Limited | Wholesale & retail | 1994 |
| Maze Marketing Ltd | Wholesale & retail | 2011 |
| Maze Studios CIC | Arts & recreation | 2010 |
| Mazen Fruit Ltd | Wholesale & retail | 2026 |
| Mazethan Ltd | Real estate | 2025 |
| Mazi Meze Limited | Hospitality | 2016 |
| Mazyk Holdings Limited | Financial services | 2026 |
| Mazz Foods Ltd | Hospitality | 2023 |
| Mazzie Company Limited | Construction | 2018 |
| Mazzy's Foods Limited | Hospitality | 2017 |
| Maz’S Beauty Palace Ltd | Health & social care | 2019 |
| MB Accounting and Advisory Limited | Professional & scientific | 2024 |
| MB Angels Childcare Ltd | Health & social care | 2024 |
| MB Bristol Limited | Wholesale & retail | 2009 |
| MB Building Services (Bristol) Limited | Construction | 2018 |
| MB Carpentry (Bristol) Limited | Construction | 2021 |
| MB Catering Consultancy Ltd | Hospitality | 2021 |
| MB Design & Build Ltd | Construction | 2020 |
| MB Estates Bristol Limited | Real estate | 2023 |
| MB Geophysical Limited | Mining & quarrying | 2017 |
| MB Glazing Systems Limited | Construction | 2022 |
| MB Magic Ltd | Hospitality | 2016 |
| MB Maintenance Solutions Ltd | Construction | 2026 |
| MB Manufacturing Limited | Manufacturing | 2022 |
| MB Mechanical Services Ltd | Construction | 2026 |
| MB Site Welding Limited | Wholesale & retail | 2010 |
| MB Therapy Ltd | Health & social care | 2024 |
| MB Wealth Limited | Financial services | 2018 |
| Mb&S Engineering Ltd | Construction | 2021 |
| Mb-Clo Services Ltd | Health & social care | 2019 |
| MBA Aviation Europe Ltd | Professional & scientific | 2023 |
| MBA Car Services Ltd | Manufacturing | 2023 |
| Mbagaya Limited | Health & social care | 2016 |
| Mbaike Productions Ltd | Other services | 2024 |
| Mbanga Limited | Transport & logistics | 2015 |
| Mbaye Securities UK Limited | Administrative & support | 2022 |
| Mbbm Ltd | Construction | 2020 |
| MBC Consultancy Limited | Professional & scientific | 2015 |
| Mbcc Group Ltd | Administrative & support | 2026 |
| Mbhele Limited | Health & social care | 2017 |
| MBL Homes (SW) Ltd | Construction | 2022 |
| MBM Building Services (SW) Limited | Construction | 2014 |
| Mbnr (SW) Ltd | Construction | 2018 |
| Mbogo United Limited | Health & social care | 2020 |
| MBP Flooring (Bristol) Limited | Construction | 2017 |
| MBP Floors and Walls Limited | Construction | 2022 |
| MBR Autos Limited | Wholesale & retail | 2016 |
| Mbsautomotive Ltd | Wholesale & retail | 2022 |
| Mbse Limited | Professional & scientific | 2023 |
| MBV Properties Ltd | Real estate | 2022 |
| MC Bristol Ltd | Households | 2024 |
| MC Engineering Incorporating Keynsham Forge Limited | Manufacturing | 2003 |
| MC Medical Consultancy Limited | Professional & scientific | 2015 |
| MC Pizza Ltd | Hospitality | 2022 |
| MC Property Rentals Limited | Real estate | 2023 |
| MC Pubco Limited | Hospitality | 2019 |
| MC Security Services Ltd | Information & communication | 2015 |
| MC Tyres and Recovery Ltd | Transport & logistics | 2009 |
| MC2 Construction Services Limited | Construction | 2025 |
| MC2 Quantity Surveying Services Ltd | Professional & scientific | 2025 |
| MCA Contractors Limited | Construction | 2025 |
| MCA Electrical Services Ltd | Manufacturing | 2019 |
| Mcadam Lloyd Limited | Wholesale & retail | 2004 |
| Mcalinden Properties Bristol Limited | Real estate | 2026 |
| Mcalinden Properties LLP | | 2024 |
| Mcalinden Property Limited | Real estate | 2016 |
| Mcarthur Davies Limited | Professional & scientific | 2010 |
| MCB Tree Management Ltd | Agriculture & fishing | 2023 |
| Mcb-Hub Ltd | Administrative & support | 2022 |
| Mcbeth Joinery Limited | Manufacturing | 2012 |
| Mcbraida PLC | Manufacturing | 1954 |
| Mcbreen Enterprises Ltd | Other services | 2019 |
| Mcbride Competitions Limited | Arts & recreation | 2023 |
| Mcburnie Properties Ltd | Real estate | 2023 |