| LOT 3 Properties Limited | Construction | 2001 |
| Loup Comble Limited | Hospitality | 1997 |
| Loverings (Combe Martin) Limited | Wholesale & retail | 1985 |
| Lower Collipriest Farm Limited | Agriculture & fishing | 1964 |
| Ludwell Partners Limited | Agriculture & fishing | 2007 |
| Luggage Locker Ltd | Wholesale & retail | 2003 |
| Luminvision Ltd | Information & communication | 2006 |
| Lurcombe Farm Company | Agriculture & fishing | 1977 |
| Luscombe Maye LLP | | 2007 |
| Lycette Care Limited | Health & social care | 2007 |
| Lyme Regis Property Limited | Administrative & support | 2005 |
| Lynwood Design Limited | Administrative & support | 2006 |
| M & B Fairchild Ltd | Construction | 2021 |
| M & S Hauliers Limited | Transport & logistics | 1993 |
| M a E Properties Limited | Real estate | 2011 |
| M B Davies Building Services Limited | Construction | 2004 |
| M. & P. Hartnell Limited | Construction | 2003 |
| M. Way & SON (Transport) Limited | Transport & logistics | 1994 |
| M.T.M. Motors/Cumbers Garage Limited | Wholesale & retail | 2003 |
| MA & EJ Bennett Limited | Agriculture & fishing | 2007 |
| Mackgills Limited | Wholesale & retail | 2003 |
| Maclean (South West) Limited | Transport & logistics | 1996 |
| Maddy's Chippy Limited | Hospitality | 2003 |
| Maer Properties Limited | Real estate | 1996 |
| Magnolia House (SW) Limited | Administrative & support | 2009 |
| Main Gate Leisure Limited | Hospitality | 1996 |
| Majestic Consulting Limited | Professional & scientific | 2001 |
| Make Southwest | Arts & recreation | 1986 |
| Malby Maps Limited | Wholesale & retail | 2012 |
| Mallward Management Limited | Hospitality | 1999 |
| Manor Farms (Yelland) Limited | Agriculture & fishing | 1955 |
| Marchand Petit Limited | Real estate | 1995 |
| Mardale Technology Limited | Wholesale & retail | 1990 |
| Marine Services (SW) Limited | Construction | 2007 |
| Markcourt Limited | Agriculture & fishing | 1999 |
| Marks Building Services Limited | Construction | 1996 |
| Marshalls Location Properties Limited | Hospitality | 1970 |
| Martin Barre Limited | Real estate | 1970 |
| Martinet Services Limited | Information & communication | 1995 |
| Matrix (Exmouth) | | 2003 |
| Matrix Heritage (NO.7) Limited | Construction | 1997 |
| Maudlin D.I.Y. Limited | | 1976 |
| Maxpro Contracting Ltd | Administrative & support | 2021 |
| MAY Flower Devon Limited | Hospitality | 2018 |
| Mcdiarmid Aviation Limited | Health & social care | 2022 |
| Mcgowan Hayes Property Limited | Real estate | 2021 |
| Mclintock and Taylor Limited | Construction | 2003 |
| MDP (South West) Limited | Construction | 2005 |
| MDR Transport Limited | Transport & logistics | 2001 |
| Merabatir Limited | Professional & scientific | 2005 |
| Mercer Properties Ltd | Real estate | 1997 |
| Merrimead Builders Limited | Construction | 2005 |
| Metalwork Limited | Professional & scientific | 2005 |
| MFV Precision Engineering Limited | Manufacturing | 2015 |
| MGL Investments Limited | Real estate | 2004 |
| Michael Chown Ruminant Consultancy Plus Ltd | Agriculture & fishing | 2011 |
| Michael Clarke Limited | Construction | 2004 |
| Michael Dark Limited | Wholesale & retail | 2003 |
| Michael S Symons Mechanical Services Limited | Construction | 2004 |
| Michael Taylor (Plymouth) Ltd | Construction | 2004 |
| MID Devon Constitutional Club Company Limited(The) | Administrative & support | 1887 |
| MID Devon Glass Limited | Manufacturing | 1993 |
| Middelmor Limited | Arts & recreation | 2025 |
| Mila Properties Ltd | Real estate | 2016 |
| Milk One Sugar Limited | Professional & scientific | 2014 |
| Mill Cross Ltd | Health & social care | 2010 |
| Miller & SON Ltd. | Real estate | 1935 |
| Minear Engineering Limited | Administrative & support | 2001 |
| Miracle Artists Limited | Administrative & support | 2005 |
| Mitchem Farming Limited | Financial services | 2004 |
| Mobile Marine Engineers Limited | Administrative & support | 2002 |
| Mobile T Limited | Wholesale & retail | 2007 |
| Modbury Developments Limited | Construction | 2003 |
| Mohul Ltd | Transport & logistics | 2015 |
| Monitor BCS UK Limited | Professional & scientific | 2003 |
| Moon Daisy Limited | Manufacturing | 2007 |
| Moor Design Limited | Administrative & support | 2006 |
| Moores Food Hall (Torbay) Limited | | 1978 |
| Moorestone Consultancy Limited | Professional & scientific | 2002 |
| Moorhayes Park Management Company (NO.3) Limited | Real estate | 2005 |
| Moorhayes Park Management Company (NO.4) Limited | Real estate | 2005 |
| Morley Homes Limited | Real estate | 2002 |
| Morse Property & Investments Limited | Real estate | 2025 |
| Mortgage Help UK Limited | Financial services | 1999 |
| Moyseys Interiors Limited | Wholesale & retail | 2005 |
| MR Modshelf Limited | Manufacturing | 1998 |
| MSW Torquay Limited | Wholesale & retail | 2003 |
| MUD Monkey Construction Limited | Construction | 2026 |
| Muirhead Finance Limited | Financial services | 1961 |
| Muirhead Financial Services Limited | Financial services | 2007 |
| Mullacott Equestrian Centre Limited | Arts & recreation | 2000 |
| Munar Ltd | Manufacturing | 2014 |
| Murch Bros (Engineers) Limited | Manufacturing | 1950 |
| Murray (Plymouth) Limited | Wholesale & retail | 2001 |
| Murray Enterprises Limited | Real estate | 2007 |
| Mutley Spice Limited | Hospitality | 2001 |
| Muxeries Consulting Limited | Professional & scientific | 2007 |
| My Handyman & Van Limited | Construction | 2019 |
| Myriad Digital Ltd | Information & communication | 2003 |
| N & S Gardiner | | 1987 |