| Move Ai Ltd | |
| Move Digital | |
| Movemeback Ltd | |
| Moving Moutains | |
| Mowden Controls Ltd | North Yorkshire |
| Moxby | |
| MPCH | |
| MPE Electronics | |
| MPH Creative | |
| Mpirical Ltd | Lancashire |
| MPL Web Design | Swansea |
| MPOS System | |
| MPS Creative | Northamptonshire |
| MPS Networks plc | West Midlands |
| MQP Electronics | Wiltshire |
| MQube Technology Ltd | |
| Mr Digital | |
| Mr Digital | |
| Mr Digital Ltd | |
| Mr Great Ltd | |
| Mr Memory | West Sussex |
| Mr Zen | |
| MRDC Software | |
| MRG Systems | Gloucestershire |
| MRM Global Ltd | |
| MRPeasy | |
| MRS Web Solutions Ltd | Hampshire |
| MSDC | |
| MSH Electronics Ltd | Dorset |
| MSI Marketing Research Reports | Cheshire |
| MSL Engineering Integrity Systems Ltd | West Sussex |
| MSP Systems Ltd | |
| MSPoweruser | Greater London |
| MSQ | Greater London |
| MSquared | |
| MSWwebdesigns | West Yorkshire |
| MT Services Computer Systems Ltd | Staffordshire |
| MTC Training | Tyne and Wear |
| mtc. | Dundee |
| MTech | |
| Mtest Labs | Greater London |
| MTI Technology | Surrey |
| MTM Agency | |
| MTN Fire and Security | |
| MTR Design | Kent |
| MTS Media Ltd | |
| MTX Studio Ltd | |
| Mucky Puddle Ltd | Glasgow |
| Mudimedia Ltd | |
| Mulberry Interactive Ltd | Dorset |