| M Reid & Sons | Agriculture & fishing | 2004 |
| M T Cartner Limited | Real estate | 2019 |
| M Templeton Construction & Joinery Services Ltd. | Construction | 2018 |
| M Templeton Holdings Ltd | Financial services | 2026 |
| M&W Security Limited | Administrative & support | 2022 |
| M.U.A. Private Limited | Public administration | 2025 |
| Mabie Projects Limited | Extraterritorial | 2012 |
| MAC Paving and Landscaping Ltd | Administrative & support | 2026 |
| Mackay Rentals Limited | Real estate | 2022 |
| Macmillan Property Development Ltd | Construction | 2014 |
| Madcan Energy Ltd | Wholesale & retail | 2020 |
| Madfc Ltd | Manufacturing | 2025 |
| Madison Music Ltd | Other services | 2006 |
| Maggie's P.O. Limited | Transport & logistics | 2021 |
| Mala Interiors Ltd | Other services | 2023 |
| Malory Nurseries | Administrative & support | 2007 |
| Mappin Estates Ltd | Professional & scientific | 2004 |
| Marchbank Catering Ltd | Wholesale & retail | 2017 |
| Marchbank Holdings Ltd | Financial services | 2025 |
| Marchbank Manufacturing Ltd | Wholesale & retail | 2017 |
| Marchhill Properties Ltd | Real estate | 2024 |
| Marle Street Property Limited | Households | 2018 |
| Martin Mcnae Photography Limited | Professional & scientific | 2006 |
| Martin Williams (Scotland) Limited | Manufacturing | 2025 |
| Matador Gardens and Homes Ltd | Construction | 2023 |
| Matariki Limited | Agriculture & fishing | 2025 |
| Mather Wind Turbine Services Limited | Manufacturing | 2015 |
| Matheson Media Ltd | Information & communication | 2021 |
| Maxwell and Mcculloch Limited | Construction | 2022 |
| Maxwell Fides Ltd | Professional & scientific | 2018 |
| Maxwelltown Roofing Services Limited | Construction | 2005 |
| MAY Peace Prevail on Earth International Ltd. | Manufacturing | 2007 |
| Mazpizza Ltd | Hospitality | 2018 |
| MBC Agri Services Limited | Agriculture & fishing | 2025 |
| Mcauley Policy and Management Ltd | Professional & scientific | 2014 |
| Mcburnie's Removals Limited | Transport & logistics | 2022 |
| Mcclure Haulage Limited | Information & communication | 2009 |
| Mccubbing Timber Harvesting Limited | Agriculture & fishing | 2012 |
| Mcdermid Distribution Limited | Transport & logistics | 2018 |
| Mcdermid Supply Company Limited | Wholesale & retail | 2007 |
| Mcdougall Commercials Holdings Limited | Other services | 2023 |
| Mcdougall Commercials Limited | Wholesale & retail | 2011 |
| Mcentee Agri Limited | Agriculture & fishing | 2024 |
| Mcewans Mechanical Services Limited | Professional & scientific | 2025 |
| MCK Forestry Limited | Agriculture & fishing | 2015 |
| Mckeown Groundworks Limited | Construction | 2007 |
| MCM Garage Services Ltd | Wholesale & retail | 2015 |
| MD Developments & Lettings Limited | Real estate | 2022 |
| MD Joinery & Construction Limited | Construction | 2023 |
| Mdte Consultants Ltd | Professional & scientific | 2018 |
| ME Steed Holdings Ltd | Financial services | 2024 |
| Megawatt Holdings Ltd | Financial services | 2019 |
| Mein Farming Company Limited | Agriculture & fishing | 2012 |
| Meladave Nominees Limited | Professional & scientific | 2007 |
| Menopause Matters Limited | Health & social care | 2001 |
| Mental Break Limited | Manufacturing | 2025 |
| Merchants of Character Holdings Limited | Financial services | 2017 |
| Merlin Office Limited | Wholesale & retail | 2012 |
| Merrick Inspection Services Limited | Construction | 2015 |
| Messrs J Rogerson (Alton) Ltd | Agriculture & fishing | 2013 |
| Messrs W. Millar (Glensone) Limited | Agriculture & fishing | 2006 |
| Metrik Solutions (Dumfries) Limited | Wholesale & retail | 2013 |
| Metrik Solutions Ltd | Wholesale & retail | 1958 |
| MF ALI Enterprises Ltd | Wholesale & retail | 2023 |
| MGC Trading Group Limited | Wholesale & retail | 2022 |
| Michael Blain Limited | Construction | 2005 |
| Michael Johnstone Transport Holdings Limited | Other services | 2021 |
| Michael Johnstone Transport Limited | Transport & logistics | 2003 |
| Middlemiss & Associates Limited | Professional & scientific | 2019 |
| Midknock Farms | | 1991 |
| Milroy Heating Ltd | Construction | 2024 |
| Minara Catering Limited | Hospitality | 2023 |
| Minnydow Properties Limited | Real estate | 2020 |
| MJ REN CON Limited | Real estate | 2019 |
| MK Jewels Ltd | Wholesale & retail | 2026 |
| Mkinternationaluk Ltd | Wholesale & retail | 2025 |
| ML Dent Ltd | Health & social care | 2022 |
| Mlle Holdings Limited | Administrative & support | 2019 |
| Mlle Trading Limited | Administrative & support | 2019 |
| MM Properties (Dumfries) Limited | Real estate | 2019 |
| MNG Consulting Limited | Administrative & support | 2017 |
| Moatwell Home Care Services Limited | Health & social care | 2024 |
| Mobile Carpets Limited | Wholesale & retail | 2007 |
| Mobile Tech Plus Limited | Wholesale & retail | 2026 |
| Mogol Ltd | Professional & scientific | 2012 |
| Mojack Media Limited | Professional & scientific | 2025 |
| Molplant Construction Limited | Construction | 1965 |
| Monact Limited | Information & communication | 2007 |
| Monaghan Jewellers Limited | Wholesale & retail | 2003 |
| Montgomerie Properties Limited | Administrative & support | 2025 |
| More Organised Ltd | Other services | 2017 |
| Morse Global Translations Limited | Professional & scientific | 2018 |
| Moss-Side Farmers | | 2001 |
| Mosspark Commercial 1 Ltd | Financial services | 2020 |
| Mosspark Commercial Ltd | Real estate | 2020 |
| Mosspark Estates 1 Ltd | Financial services | 2020 |
| Mosspark Estates Ltd | Agriculture & fishing | 2020 |
| Mosspark Residential 1 Ltd | Financial services | 2020 |
| Mosspark Residential Ltd | Real estate | 2020 |
| Moto Clan Ltd | Manufacturing | 2020 |