Keryx downgraded By: MarketMinute » Stock News September 08, 2014 at 05:28 AM EDT FBR Capital downgraded Keryx Biopharmaceuticals Inc. (Nasdaq: KERX) from a Market Perform rating to an Underperform rating sending the stock price tumbling $1.55 to $15.46. Related Stocks: Keryx Biopharm Inc