No, it's not what you think. Robert Kotick, CEO and president of Activision Blizzard, is still head of the world's biggest third-party publisher. But one of his top men, Mike Griffith - CEO & president of Activision publishing - has resigned.
He handed in his notice on April 23, meaning he's no longer CEO or president of the publisher, but will stay on with the company for at least another year (on a contract), serving as a vice-chairman of the board.
No reason has been given for the move.
Mike Griffith resigns from Activision Publishing [GamesIndustry.biz]