| ID | Name | Type |
|---|---|---|
| #9484 | Maynard International Ltd | Z |
| #9485 | Maz H. Spork | + |
| #22466 | Maziac | P |
| #20023 | McBrine Computer Products | P |
| #20041 | McFly | - |
| #9487 | McGraw-Hill Book Company UK Ltd | P |
| #9488 | McGraw-Hill [BR] | Z |
| #9489 | McGraw-Hill [ES] | Z |
| #9490 | McGraw-Hill [FR] | Z |
| #9491 | McGraw-Hill [IT] | Z |
| #9492 | McGraw-Hill [US] | Z |
| #16618 | McKlain | + |
| #9493 | McLoughlin & Co | Z |
| #9494 | McNeil | ? |
| #9495 | McNeil Software | Z |
| #20000 | McRaymond | - |
| #21888 | Mch | - |
| #19222 | Mch84 | P |
| #9496 | Mcs | ? |
| #9497 | Meadowmarsh Software | Z |