Warehouse club operator Costco Wholesale reported a decline in quarterly comparable sales and lower-than-expected sales, hurt by gasoline price deflation and a stronger dollar that reduced value of sales from overseas markets.
Shares of the third-largest U.S. retailer were down slightly at $144.95 in after-market trading on Wednesday.
Comparable sales at outlets open more than one year declined 1 percent in the quarter, including fuel and foreign currency impacts. This was below the 0.7 percent growth expected by analysts polled by research firm Consensus Metrix.
Read MoreThese 10 retailers take two-thirds of your money
Excluding the impact of fuel prices and currency, comparable sales rose 6 percent, still missing analysts' estimates of 6.20 percent growth.