Papa John's ( PZZA) was downgraded at Keybanc to hold from buy. Valuation call, as the stock approached the previous $70 price target, Keybanc said. Starbucks ( SBUX) was upgraded at Williams Capital to buy from hold. $85 price target. Company can deliver stronger growth and deserves a higher multiple, Williams Capital said. Yelp ( YELP) was upgraded at J.P. Morgan to overweight from neutral. $52 price target. Company can continue to expand margins, J.P. Morgan said. Yelp was upgraded at Wunderlich to buy from hold. $53 price target. New products can drive sales growth, Wunderlich said.