Nollenberger Capital Partners analyst Todd Greenwald has commented on the early success of Activision's Call of Duty 4: Modern Warfare, saying that it may very well outpace Halo 3's record-breaking sales. Released earlier this week, most retail stores have already sold out, with only pre-orders being assured. "Keep in mind, CoD4 is launching on four times as many platforms (360, PS3, PC, DS) as Halo 3 (360). Halo 3 has so far sold about four million units. A year ago, Call of Duty 3 sold about three million units, and we anticipate this year's version could do four million or more," he predicted.