| m3 Networks Ltd | Perth and Kinross |
| M35 Design | Dorset |
| M3ter Holdings Ltd | |
| M60 Digital Ltd | Greater Manchester |
| m8creative Ltd | |
| Maad House | |
| MAAD Ltd | Tyne and Wear |
| MaaS Scotland | |
| Maatify | |
| MAB Designs | |
| mAbsolve Ltd | |
| Mac Broadband | Essex |
| MAC Clinical Research | |
| Mac PC Zone | |
| Mac Repair - Birmingham | |
| Mac Repair - Newcastle | |
| Mac Repair - Nottingham | |
| Mac Repair Leeds Ltd | West Yorkshire |
| Mac Repair London | |
| Mac Repair Ltd | Greater Manchester |
| Mac Repairs UK | |
| Mac Solutions Bath | |
| MAC Systems | |
| Macber | |
| MacBooty | Surrey |
| MACE Systems Ltd | Bristol |
| Machine Networks Ltd | Lincolnshire |
| Machine Vision Technology Ltd | Warwickshire |
| MachiNx | |
| Mackerel Media Ltd | |
| Mackman | |
| Maclean Data Communications Ltd | Leicestershire |
| Macomics | |
| Macrium Software | Greater Manchester |
| Macro 4 | West Sussex |
| Macrodesign | Northamptonshire |
| Macsween of Edinburgh Ltd | |
| MacUpgrades.co.uk | Cambridgeshire |
| Macwiz | Oxfordshire |
| MAD Communications | |
| Mad Simple Media | |
| Made by Bridge | |
| Made by Crunch | |
| Made by Many Holdings Ltd | |
| Made in Katana UK Ltd | |
| Made In MK | Buckinghamshire |
| Made Media | West Midlands |
| Made Tech Group plc | |
| MadeBrave | |
| madeby.studio Ltd | |