| Mcgee Properties Ltd | Real estate | 2019 |
| Mcgill Commercials and Car Body Repair Limited | Wholesale & retail | 2024 |
| Mcguire Construction (AYR) Ltd | Construction | 2024 |
| Mcilwraith Contracts Ltd | Agriculture & fishing | 2022 |
| Mcinnes Technology Ltd | Information & communication | 2012 |
| Mcintosh Tree Care Experts Ltd | Administrative & support | 2022 |
| Mckechan Developments Ltd | Real estate | 2020 |
| Mckechan Holdings Limited | Financial services | 2023 |
| Mckechan Investments Limited | Real estate | 2020 |
| Mckenzie Plumbing Ltd | Construction | 2017 |
| Mckinnon & Co Ltd | Professional & scientific | 2018 |
| Mckinstry Practice Management Ltd | Professional & scientific | 2015 |
| Mckinstry Trustees Limited | Professional & scientific | 1987 |
| Mckissock Appliance Repairs Limited | Manufacturing | 2026 |
| Mcknight Accountancy & Tax Ltd | Professional & scientific | 2019 |
| Mcknight Property (Scotland) Ltd | Real estate | 2022 |
| MCL (Ayrshire) Limited | Construction | 2014 |
| Mclaughlin AYR Limited | Construction | 2000 |
| Mclaughlin Quality Instrumentation Systems Limited | Professional & scientific | 2013 |
| Mclellan Properties Ltd. | Real estate | 2002 |
| Mcleod Builders Ayrshire Ltd | Construction | 2024 |
| Mcleod Enterprises Ltd | Health & social care | 2025 |
| Mcleod Fitness Ltd | Health & social care | 2022 |
| Mcleod Self Drive Mini Diggers Ltd | Construction | 2026 |
| MCM FM Ltd | Construction | 2021 |
| Mcmail Management Consultancy Ltd | Professional & scientific | 2019 |
| Mcmath Project Management and Engineering Ltd | Construction | 2022 |
| Mcmillan's Property Maintenance Ltd | Construction | 2018 |
| Mcmillans Property Maintenance (AYR) Ltd | Construction | 2022 |
| Mcmillans Residential Property Ltd | Real estate | 2019 |
| Mcmorland & Co Ftca Limited | Professional & scientific | 2014 |
| Mcnicoll Marine Consultancy Ltd | Information & communication | 2020 |
| MCP Asset Ltd | Households | 2025 |
| MCP CCV 1, L.P. | | 2010 |
| MCP GP LP 1, L.P. | | 2010 |
| MCR Digital Media Limited | Information & communication | 2019 |
| Mcsporran Electrical Ltd | Construction | 2026 |
| Me's Coylton Ltd | Hospitality | 2022 |
| Meadow View Utilities Ltd | Construction | 2021 |
| Meat Trading LP | | 2014 |
| Mechatronic Engineering Services Ltd | Manufacturing | 2018 |
| Medical Services Scotland Limited | Health & social care | 2019 |
| Meecsa UK Limited | Wholesale & retail | 2010 |
| Mega GEN Limited | Professional & scientific | 2016 |
| Melian Limited | Information & communication | 2013 |
| Meow Medics Ltd | Professional & scientific | 2024 |
| Merchant City Market Ltd | Wholesale & retail | 2022 |
| Merg Contracts Ltd | Construction | 2022 |
| Merges Trade LP | | 2014 |
| Meriah Limited | Hospitality | 2013 |
| Meridan Corp. LP | | 2014 |
| Merryli Art Ltd | Professional & scientific | 2025 |
| Messrs C a Weir and SON Limited | Agriculture & fishing | 2022 |
| Metipol Trading LP | | 2014 |
| MFV Islander Limited | Extraterritorial | 2013 |
| MG GAS Services Limited | Construction | 2003 |
| MHH Limited | Professional & scientific | 2016 |
| Mick's Motor Service Limited | Wholesale & retail | 2015 |
| Midahe Limited | Real estate | 2022 |
| Midlothian Bard LP | | 2021 |
| Midton Hand Carwash Ltd | Other services | 2026 |
| Midtown Marketing Ltd | Administrative & support | 2020 |
| Migar Trade LP | | 2014 |
| Mighty Fast Fit Ltd | Wholesale & retail | 2026 |
| Milestone Developments (Ayrshire) Limited | Construction | 2013 |
| Milestone Developments (Construction) Limited | Construction | 2010 |
| Milestone Developments (Coylton) Limited | Construction | 2009 |
| Milestone Developments (Dalry) Limited | Construction | 2012 |
| Milestone Developments (Mauchline) Limited | Construction | 2019 |
| Milestone Developments (West Kilbride) Limited | Construction | 2015 |
| Milestone Developments Group Limited | Financial services | 2019 |
| Millbrae Limited | Arts & recreation | 2022 |
| Millennium Beauty Limited | Other services | 2007 |
| Miller Installs Ltd | Other services | 2025 |
| Millers of AYR Ltd | Hospitality | 2022 |
| Millestar Consulting Limited | Real estate | 2022 |
| Mindfullypresent CIC | Health & social care | 2022 |
| Mint Mortgages Limited | Financial services | 2021 |
| Mirabel Management LP | | 2014 |
| Mirch Masala Express Ltd | Hospitality | 2025 |
| Miromar Limited | Wholesale & retail | 2001 |
| Mistral Trade LP | | 2014 |
| MJM Decorators AYR Limited | Construction | 2022 |
| MLT Chauffeur Ltd | Transport & logistics | 2023 |
| MM Scaffolding Ltd | Construction | 2015 |
| Mm&O Ltd | Professional & scientific | 2024 |
| MMK Lanarkshire Ltd | Hospitality | 2024 |
| MNA02 Limited | Hospitality | 2026 |
| Mobile Xperts AYR Limited | Wholesale & retail | 2024 |
| Moir Environmental Limited | Professional & scientific | 2003 |
| Mojo Detailing Ltd | Wholesale & retail | 2022 |
| Molly AYR Ltd | Hospitality | 2025 |
| Monarchia (Aesthetics and Safety) Consultancy Ltd | Financial services | 2024 |
| Monday's Child Ltd | Wholesale & retail | 2026 |
| Moneil Properties Ltd | Real estate | 2025 |
| Mont DE Chèvre Ltd | Wholesale & retail | 2025 |
| Montgreenan Property Group Ltd | Real estate | 2020 |
| Moove Happy Limited | Real estate | 2025 |
| Morag James Limited | Professional & scientific | 2025 |
| Morandi Corp. LP | | 2016 |