Shares of drug-benefits management giant Express Scripts (ESRX) jumped 2.6% in mid-day trading after the company gave better than expected earnings guidance for 2013. Management said it expected adjusted earnings of $4.20 to $4.30 a share, or 12% to 15% higher than in 2012. Wall Street's consensus was $4.20, according to Thomson Reuters. It was revised downward in early November after management said in Q3 commentary that estimates were too high