| Miteq Limited | Information & communication | 2019 |
| MJH Management Ltd | Construction | 2013 |
| MJP (Property Development) Limited | Real estate | 2005 |
| MK Events Centre Limited | Agriculture & fishing | 2019 |
| MK V Physiotherapy Clinics Limited | Health & social care | 2003 |
| Mocomur Limited | Financial services | 2025 |
| Modern Facilities Services Ltd | Other services | 2015 |
| Modern Makers Collective Limited | Administrative & support | 2026 |
| Mogford Consultancy Limited | Professional & scientific | 2018 |
| Mole Productions Limited | Administrative & support | 2006 |
| Mollusc Property Ltd | Administrative & support | 2016 |
| Monday Market Street Management Limited | Real estate | 1983 |
| Monro Properties Limited | Construction | 2016 |
| Moonraker Bookkeeping Limited | Professional & scientific | 2020 |
| Moore of Devizes (Heating Design Consultants) Ltd | Construction | 2008 |
| Moore of Devizes Maintenance Two Limited | Professional & scientific | 2020 |
| Moore's Recycling Limited | Extraterritorial | 1990 |
| Moorelly Ltd | Wholesale & retail | 2023 |
| Morgan Webster Limited | Construction | 2005 |
| Moving Stories (Documentaries) Ltd | Information & communication | 2019 |
| MPS Medical-Product-Service UK Ltd | Professional & scientific | 2021 |
| MR ROD Alexander Limited | Health & social care | 2019 |
| Mtlll Ltd | Information & communication | 2025 |
| Muddy Puddles Forest & Coastal School Ltd | Education | 2019 |
| Muddy RUG Car Protection Limited | Wholesale & retail | 2020 |
| Mullings Electrical Limited | Construction | 2003 |
| Munteanu & Sons Ltd | Transport & logistics | 2023 |
| Muse Music Management Ltd | Professional & scientific | 2019 |
| Muse Music Records Ltd | Manufacturing | 2020 |
| Mustsee Limited | Wholesale & retail | 2012 |
| MW Nutrition Limited | Manufacturing | 2015 |
| MYG Limited | Other services | 2005 |
| N D a Foundation | Professional & scientific | 2011 |
| N G Holdings Limited | Financial services | 2007 |
| N Geraghty Limited | Construction | 2010 |
| N. J. Sims, Accountants Ltd | Professional & scientific | 2015 |
| Najjar Wellness Limited | Health & social care | 2025 |
| Nash Grain Systems Limited | Construction | 2011 |
| National Facilities Management Ltd | Administrative & support | 2024 |
| NCB Environmental Limited | Professional & scientific | 2016 |
| Needles Point (Milford-On-Sea) Limited | Households | 1988 |
| Neuadd Wind Power Ltd | Energy | 2015 |
| New Society (Devizes) Ltd | Hospitality | 2004 |
| Newbury Cleaning Ltd | Administrative & support | 2025 |
| Newleaf Sustainability Practice Ltd | Professional & scientific | 2013 |
| Newworldmgmt Ltd | Wholesale & retail | 2025 |
| Nextgen Leadership Ltd | Professional & scientific | 2015 |
| Nextgen Operations Ltd | Financial services | 2022 |
| Nextgen Recruits Ltd | Administrative & support | 2009 |
| NIC Payne Gardens Limited | Administrative & support | 2022 |
| Niche Estates Limited | Real estate | 2000 |
| Nicholas Davies Merchant Services Ltd | Professional & scientific | 2021 |
| Nick Wright Consulting Ltd | Professional & scientific | 2017 |
| Nimbus International Limited | Financial services | 2004 |
| NJT Accountancy and ERP Consultancy Ltd | Information & communication | 2018 |
| Nlbg Electrical Ltd | Construction | 2017 |
| Noah Housing Limited | Professional & scientific | 2020 |
| NOI Property Limited | Real estate | 2025 |
| Nordlund Limited | Hospitality | 2012 |
| North Wiltshire DAB CIC | Information & communication | 2025 |
| Northgate Corner Ltd | Construction | 2022 |
| Northgate Gardens (Devizes) Management Company Limited | Households | 2019 |
| Nosey Nubbles Ltd | Manufacturing | 2025 |
| Nova 38 Ltd | Real estate | 2019 |
| Nova Imperium Collective Ltd | Wholesale & retail | 2026 |
| Novelli Music Limited | Arts & recreation | 2013 |
| NPL Media Limited | Information & communication | 2011 |
| NR Project Solutions Ltd | Professional & scientific | 2026 |
| Nscb Ltd | Financial services | 2011 |
| Nursteed Meadows Management Company Limited | Real estate | 2010 |
| Nutrierp Enterprises Limited | Information & communication | 2025 |
| Nutristrength Limited | Wholesale & retail | 2013 |
| Nutwood House Consultancy Limited | Administrative & support | 2022 |
| O P J Carpentry Ltd | Manufacturing | 2024 |
| Oak Lane Vehicle Solutions Ltd | Wholesale & retail | 2013 |
| Oakford Ecotech Limited | Information & communication | 2025 |
| Oakford Integration Limited | Construction | 2024 |
| Oaknut Propco Ltd | Real estate | 2023 |
| Oakwood Equestrian Limited | Agriculture & fishing | 2022 |
| Obevintris Limited | Real estate | 2017 |
| Obsidian Earth Consulting Limited | Professional & scientific | 2024 |
| Ocean City (UK) Limited | Hospitality | 2011 |
| Ocean City 3388 Ltd | Hospitality | 2025 |
| Okebase Limited | Real estate | 1989 |
| Okogroup Limited | Wholesale & retail | 2019 |
| Old Orchard Street Management Company Limited | Hospitality | 1999 |
| Old Park Associates Limited | Information & communication | 2019 |
| Old Park Farm Limited | Agriculture & fishing | 1964 |
| Old Park House Management Company Limited | Real estate | 1986 |
| Old School Mews (Devizes) Management Company Limited | Households | 2021 |
| Olive Rossley Limited | Professional & scientific | 2017 |
| Olivia Nails and Spa Ltd | Other services | 2021 |
| Olivia VU Property Ltd | Real estate | 2025 |
| Omni Fitness & Performance Ltd | Arts & recreation | 2021 |
| Onyx Magazine CIC | Information & communication | 2022 |
| Opal Digital Ltd | Administrative & support | 2019 |
| Opesfidelio Financial Planning Limited | Other services | 1998 |
| Opus Accounting Limited | Professional & scientific | 2010 |
| ORE Consulting Limited | Professional & scientific | 2024 |
| Original Glory Limited | Arts & recreation | 2011 |