Oil prices held up well in 2017, brightening the outlook for energy companies. Against this backdrop, Morgan Stanley recommends a pair trade in the U.S. refining sector. A pair trade is a market neutral strategy, which helps to make profits irrespective of how the market moves by taking opposing positions in a pair of highly correlated instruments. The Analyst Morgan Stanley analyst Benny Wong upgraded shares of Delek US Holdings, Inc. DK from Equal-weight to Overweight but downgraded shares of PBF Energy Inc PBF from Equal-weight to Underweight. Morgan Stanley's price target for Delek shares was raised from $34 to $44. The firm lifted the price target for PBF Energy from $30 to $37. SourceStochastics are overbought, so the upside is over. The price will go down. $DK, Delek US Holdings, Inc. / D There is a breakout of the strong upside trend, so we can expect some downside movement or correction.Also stochastics are heading south, so there is no more room for growth for the moment. $PBF, PBF Energy Inc. / D