| Mimi & MOO Limited | Construction | 2022 |
| Mind ARC Ltd. | Education | 2025 |
| Mind Coach Solutions Limited | Professional & scientific | 2005 |
| Mind in Somerset | Health & social care | 2004 |
| Mindful Personal Training Ltd | Arts & recreation | 2019 |
| Mindfulnessuk Limited | Health & social care | 2014 |
| Mindmeplay Ltd | Information & communication | 2026 |
| Mindtechx Ltd | Health & social care | 2025 |
| Minehead & Williton Flooring Ltd | Wholesale & retail | 2018 |
| Minehead and Coast Development Trust | Other services | 2010 |
| Minehead Auto Body Repair Ltd | Wholesale & retail | 2016 |
| Minehead Cricket Club Limited | Arts & recreation | 2022 |
| Minic Limited | Financial services | 2017 |
| Minster Court Management (Taunton) Limited | Households | 1970 |
| Minster Joinery Limited | Manufacturing | 2003 |
| Minster Tippers Limited | Construction | 2000 |
| Minster Veterinary Services Limited | Professional & scientific | 2007 |
| Mircostar Ltd | Health & social care | 2019 |
| Miro Reading Ltd. | Information & communication | 2011 |
| Miscanthus Nursery Limited | Agriculture & fishing | 2009 |
| Miscrete Ltd | Construction | 2023 |
| Mishprint Limited | Wholesale & retail | 2022 |
| Mitchells Potatoes (Somerset) Ltd | Agriculture & fishing | 2000 |
| Miycleaning Limited | Administrative & support | 2020 |
| Miylaundry Ltd | Other services | 2025 |
| Mizar Southwest Limited | Construction | 2020 |
| MJ Accommodation Limited | Hospitality | 2019 |
| MJ Cleaning SW Ltd | Administrative & support | 2024 |
| MJ Home Care Staffing Limited | Administrative & support | 2018 |
| MJ Redwood Holdings Ltd | Financial services | 2019 |
| MJ Support Staffing Limited | Health & social care | 2016 |
| MJH Electrical Services Ltd | Construction | 2015 |
| MJI South Property Ltd | Real estate | 2024 |
| Mjlc Consulting Ltd | Information & communication | 2025 |
| Mjml Holdings Limited | Financial services | 2012 |
| MJP Turf & Gardens Ltd | Administrative & support | 2025 |
| MJR Healthcare Ltd | Health & social care | 2023 |
| MJR Healthcare Recruitment Ltd | Administrative & support | 2022 |
| Mjss Group Limited | Professional & scientific | 2019 |
| MK Property Maintenance Southwest Ltd | Manufacturing | 2026 |
| MK120 Ltd | Wholesale & retail | 2023 |
| MKP Health Care Ltd | Administrative & support | 2025 |
| ML Audit LLP | | 2023 |
| MLE Property Management Limited | Professional & scientific | 2026 |
| MLR Care Limited | Financial services | 2025 |
| MLR Care Support Services Limited | Financial services | 2025 |
| Mm-Training and Consultancy Limited | Education | 2011 |
| MMA105 Ltd | Transport & logistics | 2025 |
| MMG Dairy Farmers Limited | Other services | 2023 |
| MMR Property Consultants Limited | Real estate | 2009 |
| MNC Soft Care Ltd | Health & social care | 2018 |
| Moatwell Holdings Limited | Financial services | 2021 |
| Mobile Pro Limited | Wholesale & retail | 2023 |
| Moda CPS Limited | Wholesale & retail | 2012 |
| Modellers Loft Limited | Wholesale & retail | 2016 |
| Moderator Services Ltd | Information & communication | 2015 |
| Modern Home Equipment Limited | Wholesale & retail | 1964 |
| Modern Rustic Ltd | Hospitality | 2002 |
| Modular Software Development Limited | Information & communication | 2020 |
| Modular Software Development Services Limited | Information & communication | 2023 |
| Modus Contracts Limited | Manufacturing | 2015 |
| Modus Furniture Limited | Manufacturing | 2000 |
| Modus Holdings Limited | Financial services | 2018 |
| Mogl Property Ltd | Real estate | 2024 |
| Mohammed Amir & Partner Investments Limited | Real estate | 2025 |
| Mojo Live Limited | Administrative & support | 2025 |
| Mojo Networks Ltd | Information & communication | 2019 |
| Monart Spa Limited | Other services | 2018 |
| Moncasso Ltd | Wholesale & retail | 2021 |
| Monkerton Holdings Limited | Construction | 2018 |
| Monkey Tennis Ltd | Professional & scientific | 2025 |
| Monksilver GP Limited | Professional & scientific | 2006 |
| Monksleigh Limited | Professional & scientific | 2008 |
| Monkton Building & Developments Ltd | Construction | 2017 |
| Monkton ELM Garden Centre Limited | Wholesale & retail | 1999 |
| Montaz Engineering Solutions Ltd | Wholesale & retail | 2009 |
| Montaz Rentals Limited | Real estate | 2022 |
| Montys Hamlet Services Limited | Households | 2001 |
| Monument Hearing Care Ltd | Health & social care | 2024 |
| Mood Products Limited | Wholesale & retail | 2024 |
| Moon Farm Limited | Financial services | 2022 |
| Moon Tree Ltd | Professional & scientific | 2014 |
| Moonshine Bar Taunton Limited | Hospitality | 2024 |
| Moor Lane Investments Limited | Real estate | 2013 |
| Moore & Moore | Financial services | 2024 |
| Moore Scarrott Audit Limited | Professional & scientific | 2023 |
| Moore Scarrott Corporate Services Limited | Extraterritorial | 2011 |
| Moore Scarrott Finance Limited | Financial services | 2011 |
| Moore Scarrott Financial Planning Limited | Extraterritorial | 2011 |
| Moore Scarrott Forensic Limited | Professional & scientific | 2011 |
| Moore Scarrott Group Limited | Administrative & support | 2015 |
| Moore Scarrott Healthcare Limited | Professional & scientific | 2019 |
| Moore Scarrott Law Limited | Professional & scientific | 2011 |
| Moore Scarrott Limited | Professional & scientific | 2002 |
| Moore Scarrott Rural Ltd | Professional & scientific | 2021 |
| Moore Scarrott Tax Limited | Professional & scientific | 2011 |
| Moore Scarrott Training and Education Limited | Education | 2011 |
| Moore Scarrott Wealth Advisory & Real Estate Limited | Professional & scientific | 2025 |
| Moores Paws Limited | Other services | 2022 |
| Moorhaven Partnership Limited | Construction | 2010 |