Larry Kaplan, one of the co-founders of Activision was also with Jay Miner, a co-creator of the Amiga Computer both of whom were recent decamps from Atari. The company was originally founded as Hi Toro to then change it’s name to Amiga to get itself placed ahead of Apple and Atari in the phonebook.
The company had been founded on a conditional loan from Atari which gave it a deadline for payback on which all of the technology developed would revert back to Atari.
As history turned out, Commedorre bailed out the fledgling Amiga Corp and Atari would go on to create it’s own 68k based line, the Atari St.