In 2007, Activision merged with Vivendi Games, owner of World Of Warcraft developer Blizzard, in a deal worth over $18 billion.
However, Kotick told Games Informer about a meeting in the 1990s when he could have picked up the studio for considerably less.
At a dinner with educational software provider Davidson & Associates in 1995, Kotick mocked the firm over its $7m deal to acquire Blizzard.
"That year Activision probably had $60m in revenues. They said they paid $7m dollars for Blizzard. I'm like, 'Are you out of your minds?'," he said.
"They're like a contract developer! They have Warcraft but what else do they have? You paid $7m! That's insane!"
Aside from his own missed opportunity, Kotick also revealed that Blizzard founder Mike Morhaime was equally put out by the deal, but for different reasons.
"I was talking to Mike Morhaime the other day and I said, 'You know, I could have bought you for $7m and instead it was $7bn'," Kotick revealed.
"He said, 'Yeah, could you imagine if I had just held out for the $7bn instead of the $7m?'"