** Morgan Stanley downgrades Swiss dental implant maker Straumann STMN.S to "underweight" from "equal-weight"
** The broker cites U.S. volume growth pressures and margin headwinds from Straumann's China ramp up as potential challenges to its premium valuation
** The company announced in June that it was cutting 250 jobs at its Villeret site, seeking to localise its production for the Chinese market
** J.P. Morgan maintains its "neutral" rating for Straumann, saying that upcoming Q3 consensus expectations factor in foreign exchange headwinds but that Asia Pacfic sales appear to be estimated too high
** Shares are down 1.3%
** Including today's fall, the stock has dropped by 25% YTD