Forbes says It was antitrust concerns and disagreement on the size of a breakup fee.<p><a href="http://www.forbes.com/sites/ryanmac/2014/08/25/amazon-pounces-on-twitch-after-google-balks-due-to-antitrust-concerns/" rel="nofollow">http://www.forbes.com/sites/ryanmac/2014/08/25/amazon-pounce...</a>