MillerCoors, the North American joint venture between SABMiller and Molson Coors, seemed to have timing on its side when it launched last summer. The partnership became official only weeks before news that its largest competitor, Anheuser-Busch, would soon become part of the even larger InBev. The news could have been troubling to the new partnership, but becoming a more powerful competitor is exactly what brought the two brewers together and what it spent months preparing for ahead of the merger.