Improving labor market, rising disposable income and elevated consumer sentiment have ushered confidence in Costco Wholesale CorporationCOST that continued with its stellar comparable sales (comps) performance in 2018. While major chains are grappling with sluggish store and mall traffic as consumers switch to online shopping, Costco seems somewhat resilient to the challenging retail backdrop. Excluding the impact of foreign currency fluctuations and gasoline prices, Costco's comps for the month under review rose 5.8%.