| Mccowen-Smith Ltd. | Real estate | 2016 |
| Mcguires Wires Ltd | Construction | 2022 |
| Mckerrow History Ltd | Education | 2023 |
| Mcla Properties Limited | Real estate | 2019 |
| Mcnamara & SON Limited | Agriculture & fishing | 2006 |
| Mcqueen Jones Training Ltd | Construction | 2024 |
| MDB Developments Ltd | Construction | 2006 |
| Mdmy Capital Limited | Professional & scientific | 2018 |
| Meadow Rise (Northam) Management Company Limited | Real estate | 2017 |
| Meadow Rise Holdings Ltd | Construction | 2021 |
| Medhurst Ltd | Transport & logistics | 2024 |
| Medic 360 Ltd | Health & social care | 2023 |
| MEE WEI Limited | Hospitality | 2018 |
| Mehbe Ltd | Wholesale & retail | 2023 |
| Melbury Hill Properties Limited | Construction | 2007 |
| Menday Property Limited | Real estate | 2026 |
| Menzies Risk and Security Management Ltd | Other services | 2021 |
| Merlin Fabrics Limited | Wholesale & retail | 2014 |
| Merlin Properties (SW) Ltd | Real estate | 2015 |
| Merr Consulting Ltd | Information & communication | 2025 |
| Merrick Real Estate Limited | Professional & scientific | 2011 |
| MET Digital Limited | Administrative & support | 2025 |
| Metal Clad Ltd | Manufacturing | 2019 |
| Mettle Adventures Ltd | Administrative & support | 2020 |
| Mezzo Labs Ltd | Professional & scientific | 2006 |
| MGF Accountants Limited | Professional & scientific | 2024 |
| MGX Consultants Ltd | Professional & scientific | 2017 |
| MH Gardens Limited | Extraterritorial | 2024 |
| Michael Bainbridge Ltd | Construction | 2018 |
| Michael Boundy Ltd | Construction | 2026 |
| Midnight & Moss Ltd | Administrative & support | 2024 |
| Midway Motors (SW) Ltd | Wholesale & retail | 2015 |
| Midways Flats Management Company Limited | Real estate | 2008 |
| Midwinter Koval Estate Agents Limited | Real estate | 2002 |
| Mill Lane Residents Association Limited | Administrative & support | 1987 |
| Milltown Developments Devon Limited | Construction | 2024 |
| Mindful Growth Solutions Ltd | Administrative & support | 2024 |
| Mindful Nurse Ltd | Health & social care | 2025 |
| Mini Bunny Dragon Limited | Hospitality | 2026 |
| Miniature Autoworld Ltd | Other services | 2026 |
| Mist Workshops Ltd | Professional & scientific | 2023 |
| MJ & RH Medical Limited | Health & social care | 2014 |
| MJ Lifts Ltd | Professional & scientific | 2019 |
| MJK Consultancy Ltd | Administrative & support | 2010 |
| MJM Sports (Licenses) Ltd | Manufacturing | 2023 |
| MJM Sports Ltd | Wholesale & retail | 2005 |
| MJS Building Maintenance Ltd | Construction | 2015 |
| MK Millennium Developments Ltd | Real estate | 2023 |
| MK Millennium Limited | Construction | 2007 |
| MLJ Accountants (SW) Ltd | Professional & scientific | 2025 |
| MLS Management Service Ltd | Real estate | 2026 |
| Mobile Caterers Properties Limited | Real estate | 1993 |
| Mobility Solutions Direct Ltd | Wholesale & retail | 2019 |
| Mobitech Mobiles Ltd | Wholesale & retail | 2021 |
| Mojo Estates Ltd | Real estate | 2025 |
| Momentum Devon C.I.C. | Health & social care | 2020 |
| Money Advice Office Ltd | Financial services | 2022 |
| Mongoose Sports & Entertainment Limited | Professional & scientific | 2015 |
| Monkeydrill Limited | Arts & recreation | 2011 |
| Monkleigh Barton Limited | Construction | 2004 |
| Monumentalism Limited | Manufacturing | 2024 |
| Moorlogic Ltd | Information & communication | 2026 |
| Moose Hall Property Management Limited | Other services | 2024 |
| More Maison Ltd | Real estate | 2019 |
| Mortehoe Apartments Management Limited | Households | 1995 |
| Mortgages With Joy Limited | Financial services | 2011 |
| Morthoe Station Management Company Limited | Households | 2014 |
| MOT @ D and S Limited | Wholesale & retail | 2024 |
| Mount Sandford Green Management Company Ltd | Households | 2017 |
| Mount Stephen Education Ltd | Administrative & support | 2024 |
| Mour Digital Ltd | Information & communication | 2022 |
| Moving Future Limited | Professional & scientific | 2002 |
| MPL Construction Services Ltd | Construction | 2023 |
| Mrs(Devon) Limited | Professional & scientific | 2021 |
| Msck Plastering Ltd | Construction | 2026 |
| MT Plastering Ltd | Construction | 2023 |
| Muddipuddle Farm Limited | Agriculture & fishing | 2017 |
| Multi Story Theatre Company LLP | | 2025 |
| Multiverse Hospitality Ltd | Hospitality | 2017 |
| Multiverse Pizza Ltd | Hospitality | 2023 |
| Munro News Limited | Information & communication | 2004 |
| Murphy and Neville Limited | Professional & scientific | 2007 |
| Must Have Products Limited | Wholesale & retail | 2017 |
| Muttercare Ltd | Other services | 2007 |
| My Car Agent Ltd | Professional & scientific | 2025 |
| My Favourite Cottages Limited | Hospitality | 2018 |
| My Mate Café Ltd | Hospitality | 2018 |
| Mytaxi Barnstaple Limited | Transport & logistics | 2025 |
| N D Joy Autos Limited | Wholesale & retail | 2003 |
| N J Cook Limited | Agriculture & fishing | 2014 |
| N M a Flooring Limited | Construction | 2009 |
| N.D.C.I.Limited | Real estate | 1964 |
| N.H.C.A. Limited | Arts & recreation | 1987 |
| N.J. Luckett Limited | Construction | 2003 |
| N.L.D. Farming Limited | Construction | 2005 |
| N.W. Pearce (Electrical) Limited | Construction | 2005 |
| N1 FAN Group Ltd | Wholesale & retail | 2023 |
| NAK (Barum) Ltd | Financial services | 2019 |
| Nalu Homes SPV 105 Limited | Construction | 2018 |
| Nalu Homes SPV 106 Limited | Construction | 2018 |