| Magdalen House Management Limited | Households | 2004 |
| Magic Machines Limited | Manufacturing | 2016 |
| Maha Bharat Torquay Ltd | Hospitality | 2026 |
| Maha-Bharat Torbay Limited | Hospitality | 2017 |
| Maidencombe House Management Company Limited | Households | 1989 |
| Maidenfield Management Limited | Households | 2014 |
| Mailchatter Ltd | Extraterritorial | 2004 |
| Maintain Direct Limited | Administrative & support | 2016 |
| Maintain Greater London Limited | Administrative & support | 2015 |
| Maintain South West LLP | | 2015 |
| Maintain SW Limited | Construction | 2024 |
| Maintenance Assistance Services Inc Limited | Manufacturing | 2012 |
| Maisonforte Limited | Real estate | 2024 |
| Makevents Limited | Arts & recreation | 2005 |
| Malibu Surf Company Ltd | Wholesale & retail | 2023 |
| Mallands Care Limited | Health & social care | 2002 |
| Mandown Recruitment Services Ltd | Administrative & support | 2018 |
| Mane Events (South West) Ltd | Hospitality | 2016 |
| Mane Property Developments Ltd | Real estate | 2026 |
| Mango Property Software Limited | Information & communication | 2021 |
| Manor Bourne Road Maintenance Limited | Real estate | 1964 |
| Manor Court (Torquay) Limited | Households | 1988 |
| Manor Court Management (Paignton) Limited | Real estate | 2004 |
| Manor Lodge Developments Limited | Real estate | 2012 |
| Manor Mews Management Company (Torquay) Limited | Households | 2007 |
| Manor View Flats Management Company Limited | Households | 2002 |
| Manorglade Court (Torquay) Limited | Real estate | 1988 |
| Manormead House Management Company Limited | Households | 2002 |
| MAP Trade Frames Ltd | Wholesale & retail | 2020 |
| Maranatha Enterprises Limited | Health & social care | 2021 |
| Marble Court (Torquay) Ltd | Real estate | 2013 |
| Marc'H - TAM Melem Yaoued 44 Limited | Transport & logistics | 2019 |
| Marina Court (Paignton) RTM Company Limited | Households | 2005 |
| Marina Quay (Apartment Block Number One) Management Company Limited | Households | 1997 |
| Marina Quay (Apartment Block Number Two) Management Company Limited | Households | 1997 |
| Marina Quay Car-Park Management Company Limited | Households | 2002 |
| Marina Quay Management Company Limited | Households | 1997 |
| Marina View Kingswear Limited | Households | 1991 |
| Marine & Construction Services (Dartmouth) Ltd | Construction | 2016 |
| Marine Electric Power Solutions Ltd | Professional & scientific | 2019 |
| Marine Fuel Torquay Ltd | Wholesale & retail | 2019 |
| Marine Mount Management Company Limited | Real estate | 1989 |
| Mark Gaughan Limited | Information & communication | 2011 |
| Mark James Music Limited | Extraterritorial | 2015 |
| Mark Ward Accountants Limited | Professional & scientific | 2010 |
| Mark Warner IT Services Limited | Extraterritorial | 2011 |
| Market Delve Ltd | Wholesale & retail | 2023 |
| Market JEW Street Management Limited | Households | 2014 |
| Markham Court Management (2009) Limited | Households | 2009 |
| Marldon Service Station Limited | Wholesale & retail | 1957 |
| Marldon Vale Electrical Ltd | Construction | 2021 |
| Marlico Limited | Wholesale & retail | 2003 |
| Marscastle Ltd | Information & communication | 2023 |
| Marsh Tyres & Autos Cullompton Limited | Wholesale & retail | 2019 |
| Marsland Court Limited | Households | 2014 |
| Marstan Villa Ltd | Hospitality | 2022 |
| Martin@Bay Roofing Contractors Limited | Construction | 2012 |
| Martinique Gardens Management Co Limited | Households | 2025 |
| Martyn Ashcroft Limited | Hospitality | 2015 |
| Marvellous Bear Limited | Information & communication | 2021 |
| Marymead Limited | Professional & scientific | 2013 |
| Massage Yoga Therapy Ltd | Other services | 2019 |
| Massimiliano Italia Limited | Hospitality | 2006 |
| Massing Ventures Ltd | Hospitality | 2026 |
| Master Butchers (Torquay) Limited | Wholesale & retail | 2009 |
| Master Diffusion Limited | Wholesale & retail | 2018 |
| Masts Management Company Limited | Households | 2006 |
| Matahari Gold Ltd | Wholesale & retail | 2026 |
| Matpro Limited | Arts & recreation | 1990 |
| Maximum Motors Limited | Wholesale & retail | 1998 |
| Maxstoke Court Management Company Limited | Households | 1986 |
| Mayflower Court Limited | Households | 1972 |
| Maymark Ltd | Wholesale & retail | 2021 |
| Maypool Investments Limited | Real estate | 2008 |
| MB Data Process Limited | Professional & scientific | 2017 |
| MBS (Exeter) Limited | Wholesale & retail | 2018 |
| MC South West Limited | Financial services | 2024 |
| MCB Electrical SW Limited | Construction | 2026 |
| Mccarthy & Co Estate Agents Limited | Real estate | 2013 |
| Mccarthy Contracting & Development Limited | Construction | 2011 |
| Mccarthy Developments SW Ltd | Construction | 2023 |
| Mccarthy Electrical (SW) Limited | Construction | 2016 |
| Mccarthy External Systems Ltd | Construction | 2021 |
| Mccarthy Holdings SW Ltd | Financial services | 2021 |
| Mccarthy Homes SW Ltd | Construction | 2021 |
| Mccarthy Homes Torbay Ltd | Real estate | 2021 |
| Mccaulay's Health & Sport Limited | Arts & recreation | 1998 |
| Mccluskey Surveyors Ltd | Professional & scientific | 2020 |
| MCD Independent Financial Advice Ltd | Financial services | 2017 |
| Mcdonald Bricklayers Limited | Construction | 2008 |
| Mcgaw Accounting Ltd | Extraterritorial | 2022 |
| MCM Plumbing & Heating Ltd | Construction | 2022 |
| MCS Motors Ltd | Wholesale & retail | 2025 |
| MD Elite Cleaning Services Ltd | Administrative & support | 2020 |
| MD Social Care Consultants Ltd. | Professional & scientific | 2013 |
| MDP Development South West Limited | Construction | 2020 |
| ME and MRS Jones Deli Limited | Wholesale & retail | 2015 |
| Mead Storage Limited | Administrative & support | 2017 |
| Mead Units Limited | Administrative & support | 2018 |
| Meadfoot (Kilmorie Land) Limited | Households | 1969 |