Wells Fargo analyst Judson Bailey downgraded U.S. Silica (SLCA) to Market Perform and lowered his price target for the shares to $15 from $20. Downside risk for completion activity over the next few quarters and negative pricing and demand data points already rolling in for pressure pumping create risk to consensus estimates, Bailey tells investors in a research note. The analyst believes the pressure pumping market is already weakening. Bailey this morning also downgraded shares of C&J Energy Services (CJ), FTS International (FTSI) and Keane Group (FRAC).