JPMorgan analyst Paul Coster downgraded 3D Systems (DDD) to Underweight from Neutral and lowered his price target for the shares to $7 from $8. The stock in premarket trading is down 9%, or 74c, to $7.41. The company posted "mixed" Q2 results and management's narrative "was gloomy" owing to weakness in the autos sector, lumpy ordering of a large enterprise customer, and a pause in metal systems sales, Coster tells investors in a research note. After reviewing the results, the analyst sees no reason for 3D Systems to trade at a premium to peer Stratasys (SSYS).