| Media Gem Web Design | East Sussex |
| Media Hut | Nottinghamshire |
| Media Lounge | |
| Media Matters Technology Ltd | Hampshire |
| Media Orb Ltd | Somerset |
| Media Shark | |
| Media Street Ltd | Devon |
| Media Surgery | Aberdeen |
| Media Zoo | |
| MediaClash Ltd | Somerset |
| Mediacopy | Shropshire |
| Mediadog | |
| MediaGorilla Ltd | Aberdeen |
| Mediahawk Ltd | Buckinghamshire |
| Mediam Communications Ltd | Greater London |
| MediaSage Digital Ltd | Hampshire |
| MediaSpin | Greater Manchester |
| Mediatonic | |
| Mediatopia | Bristol |
| Mediatron Ltd | Hampshire |
| Mediatube Ltd | |
| Mediaworks | |
| MediaWorkx Creative Design | West Midlands |
| Medical Imaging Partnership Ltd | |
| Medical Imaging Systems | Greater London |
| Medical Systems Ltd | Cardiff |
| Medico Partners Ltd | |
| Medicxi | |
| Medincle Ltd | |
| MedInvent Ltd | |
| MediShout Ltd | |
| MediSieve | Greater London |
| Medisoft Ltd | |
| MediStrava | |
| MEDITICE Ltd | |
| Medloop Ltd | |
| Medmin | |
| MedPharm Ltd | |
| MedTech Investing Europe Forum | |
| Medway Computers | Kent |
| Medwise.ai | |
| Meeow | West Yorkshire |
| Meet-Ting | |
| MeetspaceVR | |
| Meetupcall | South Yorkshire |
| Megahertz Broadcast Systems Ltd | Cambridgeshire |
| Megganet | Fermanagh and Omagh |
| MeiraGTx Ltd | |
| MelBek Technology Ltd | Suffolk |
| Melcom Electronics Ltd | Surrey |