Wholesale club Costco Wholesale Corporation (NASDAQ: COST ) reported 7.8-percent net sales growth for December. Comps rose 6.1 percent for the total company, thanks to a 7.5-percent increase in U.S. comps. Excluding the impact of gasoline prices, forex and accounting changes related to ASC 606, total company comps rose 7 percent, with U.S. comps up 7.1 percent.