The agency beat off competition from the brewer's other roster agencies, LatinWorks in Austin and Cannonball in St Louis.
The beer, a lime-flavoured version of Bud Light, has been likened to Miller Chill, and has a marketing spend of around $35 million.
Meanwhile, Y&R's Chicago office has lost the $50 million Miller Chill account to Saatchi & Saatchi New York.
Young & Rubicam handled most of the work for the lime- and salt-flavoured beer's launch last year, but was never officially designated as its agency of record.