| Migami Ltd | Wholesale & retail | 2018 |
| Mill Lane Wellington Management Company Limited | Households | 2020 |
| Milton and Chambers Limited | Manufacturing | 2023 |
| Mimax Properties Limited | Real estate | 2024 |
| Mimax Solutions Limited | Professional & scientific | 2017 |
| Minkypips Ltd | Hospitality | 2026 |
| Miraviva Travel Limited | Administrative & support | 2012 |
| Mirrorguard Ltd | Wholesale & retail | 2012 |
| MJC Financial Planning Limited | Financial services | 2002 |
| MK Test Group Limited | Manufacturing | 2008 |
| MK Test Holdings Limited | Professional & scientific | 2008 |
| Mnpr Magazine Limited | Wholesale & retail | 2018 |
| Molly Elizabeth Brown Ltd | Health & social care | 2024 |
| Montford Finance Limited | Financial services | 2023 |
| Monument Holdings SW Ltd | Wholesale & retail | 2025 |
| Monument Inns Limited | Real estate | 2013 |
| Monument Motors Wellington Limited | Wholesale & retail | 2012 |
| Monumental Change Limited | Health & social care | 2018 |
| Moon Consultancy Limited | Information & communication | 2013 |
| Moonfox Trading Ltd | Wholesale & retail | 2016 |
| Moralee Heath Ltd | Financial services | 2026 |
| More Chicken Ltd | Hospitality | 2022 |
| Morlogistics Ltd | Transport & logistics | 2024 |
| Morwind Ltd | Energy | 2020 |
| Moss Joinery Limited | Manufacturing | 1999 |
| Motalines (SW) Limited | Wholesale & retail | 2014 |
| Mount Vets Farm Practice Ltd | Professional & scientific | 2023 |
| Mount Vets Limited | Professional & scientific | 2014 |
| Move Media Limited | Information & communication | 2008 |
| MR TLC Limited | Wholesale & retail | 2020 |
| Mrsi Property Consultancy Ltd | Professional & scientific | 2022 |
| MT Accounts Ltd | Professional & scientific | 2012 |
| Mundy Veneer Holdings Limited | Financial services | 2021 |
| Mundy Veneer Limited | Wholesale & retail | 1998 |
| Murphy Allen Ltd | Professional & scientific | 2025 |
| Musec Global Limited | Administrative & support | 2024 |
| MVA Motor Company Limited | Wholesale & retail | 2024 |
| MW Timber Haulage Ltd | Transport & logistics | 2012 |
| MWX Property Ltd | Real estate | 2026 |
| My Dental Hygienist Ltd | Health & social care | 2015 |
| My Ultimate PA Limited | Administrative & support | 2023 |
| Mypaylist Ltd | Information & communication | 2025 |
| N Riley Limited | Construction | 2002 |
| Nancekivell & Partners Ltd | Real estate | 2021 |
| Natri-Pet Limited | Manufacturing | 2025 |
| Need Training Ltd | Education | 2025 |
| Nest Associates Ltd | Real estate | 2020 |
| Netherclay House Ltd | Health & social care | 2025 |
| Netyourworth Limited | Wholesale & retail | 2017 |
| New Horizons Somerset Community Interest Company | Administrative & support | 2019 |
| Newpole Livestock Ltd | Agriculture & fishing | 2013 |
| Newton Equine Services Ltd | Agriculture & fishing | 2012 |
| Nickolls Ltd | Health & social care | 2018 |
| Nidh Retail Limited | Financial services | 2026 |
| Nina Developments Ltd | Construction | 2019 |
| Nisus Holdings Ltd | Financial services | 2025 |
| Nora Mystic Ltd | Administrative & support | 2025 |
| Norrislight Limited | | 1982 |
| North Somerset Mindful Consultancy Ltd | Health & social care | 2020 |
| Northfields Chiropractic Ltd. | Other services | 2015 |
| Norton Optical Services Ltd | Wholesale & retail | 2025 |
| Nova Status Ltd | Professional & scientific | 2019 |
| Novexe Ltd | Professional & scientific | 2025 |
| NSP Plant Engineering Welding Ltd | Wholesale & retail | 2012 |
| Numbereight Management Ltd | Real estate | 2025 |
| NURTURED4LIFE Limited | Health & social care | 2021 |
| Oake View Close Management Company Ltd | Real estate | 2026 |
| Oakfield Carpentry and Building Limited | Construction | 2018 |
| Oakleaf Cladding Ltd | Construction | 2023 |
| Oceans of Silver Ltd | Wholesale & retail | 2020 |
| Ochre Finishing Technologies Ltd | Wholesale & retail | 2010 |
| Octopus Transport UK Ltd | Transport & logistics | 2025 |
| Office Reality Ltd | Wholesale & retail | 2004 |
| OIL Warm Limited | Manufacturing | 1996 |
| Olas Properties Ltd | Real estate | 2024 |
| Old Charm Properties (SW) Limited | Construction | 2019 |
| Olde Mill Ltd | Manufacturing | 2014 |
| Olipep Limited | Real estate | 2023 |
| One Stop Sales Consultancy Ltd | Administrative & support | 2020 |
| One to One Home Care Limited. | Health & social care | 2006 |
| One Unicorn Limited | Professional & scientific | 2017 |
| ONEZERO3 Solutions Limited | Administrative & support | 2010 |
| Openstreet Limited | Wholesale & retail | 2026 |
| Optimise Sports & Fitness Ltd | Health & social care | 2022 |
| Oracle Fire Holdings Ltd | Financial services | 2025 |
| Oracle Fire Protection Ltd | Public administration | 2022 |
| Oracle Fire Sprinklers Limited | Public administration | 2022 |
| Oracle Fire Suppression Ltd | Public administration | 2022 |
| Osteo and Physio Wellington Ltd | Other services | 2021 |
| Osteothai Ltd | Health & social care | 2024 |
| Otterman Commercial Ltd | Real estate | 2026 |
| OUR Embassy Community Kitchens CIC | Hospitality | 2024 |
| Outlands Limited | Agriculture & fishing | 1988 |
| Overtake Couriers Limited | Transport & logistics | 2026 |
| P & M Roofing Supplies Limited | Construction | 2017 |
| P Daddy's POP UP Kitchen CIC | Hospitality | 2021 |
| P E Management (SW) Ltd | Professional & scientific | 2020 |
| P K Installations Limited | Construction | 2017 |
| P T Trustees (NZ) Limited | | 2023 |
| P&N Hospitality Ltd | Hospitality | 2024 |