Shares of Costco Wholesale Corporation ( COST ) rose roughly 1.7% following comparable-store sales results for May, the four weeks ended Jun 1, 2014, that bettered analysts' expectations. Excluding the effect of gasoline prices and foreign currency fluctuations, Costco's comparable-store sales for the period jumped 6%. Excluding the effect of inflation in gasoline prices and impact of foreign currency fluctuations, Costco's comparable-store sales for May rose 6%, reflecting comparable sales growth of 6% at its U.S. locations and 7% at international outlets.