The valuation isn't as attractive, as the stock is up 50% from its lows and trades at a steep premium to its peers, Goldman said. PerkinElmer ( PKI ) was downgraded to neutral from buy at Bank of America/Merrill Lynch. $52 price target. The company is facing near-term margin headwinds, analysts said. PulteGroup ( PHM ) was downgraded to neutral from overweight at JPMorgan. $18 price target. The CEO resignation adds uncertainty to the thesis, JPMorgan said. Waters ( WAT ) was downgraded to neutral from buy at Bank of America/Merrill Lynch. $137 price target. The company trades at a premium to its peers, but faces difficult near-term comps, analysts said. Western Gas Partners ( WES ) was upgraded to hold at TheStreet Ratings. You can view the full analysis from the report here: WES. Xylem ( XYL ) was upgraded to buy from neutral at Sterne Agee. $52 price target.