1. Companies starting with M:

      M Network
      M2K
      Machine Games
      Machineworks NW
      MacPlay
      MacSoft
      Mad Hatter Software
      Magic Kinder
      Magic Lantern
      Magic Wand Productions
      Magnetic Fields
      Majesco Entertainment
      Make-A-Wish Foundation
      Malachite
      Malfador Machinations
      Manifesto Games
      Marjacq Micro
      Mark Data Products
      Maryland Model II Games
      Massive Entertainment
      Masterplay
      Mastertronic
      Mastiff
      Matchup
      Matrix Games
      Mattel Interactive
      Matthias Wegerhoff
      Maxis
      Maxxdelphisite
      Med Systems Software
      Medalist International
      Media Art
      Media Molecule
      Media Technology
      Mediagenic
      Megabyte Rodeo
      MegaTech Software
      Melbourne House
      Meldac
      Melesta
      Menara Games
      Mentor Interactive
      Meridian 4
      Merscom
      Mertin 2
      Metalgrass Software
      Micro League Sports
      Micro Matrix
      Micro Pro Systems
      MicroBurst
      Microcomputer Games
      Microdeal
      Microflair Associates
      Microforum
      Microids
      MicroIllusions
      MicroLeague Interactive
      Microplay
      Microprose
      Microsoft Game Studios
      Microsoft
      Midway
      Miles Computing
      Mind Products
      Mindcraft
      Mindscape
      Minliu Soft
      Mirage Entertainment
      Mirage Interactive
      Mirage Studios
      Mithis Entertainment
      ML Enterprises
      Monkey Bar Games
      Monkey Studios
      Monolith
      Monte Cristo Games
      Mops Computer Systems
      MoraffWare
      Morgan Interactive
      Most Wanted Entertainment
      Mountain King Studios
      Mousechief
      Mr. Chip Software
      MTV Games
      MTV
      Mudpuppy Studios
      Mumbo Jumbo
      Muse Software
      Music Games International
      MVP Software
      Myelin Media
      Mystery Studio
      Mystique
      Mythic Entertainment

      Note: bolded names indicate companies that released a game within the last twelve months.