Costco Wholesale Corp. yesterday reported net sales of $14.94 billion for the month of December, the five weeks ended December 31, 2017, an increase of 14.3 percent from $13.07 billion during the similar period last year.
For the first 17 weeks of fiscal year 2018 ended December 31, 2017, Costco reported net sales of $46.06 billion, an increase of 11.9 percent from $41.18 billion reported during the similar period last year.
This year's December retail month had one additional shopping day as compared to last year due the calendar shift of New Year's Day. The shift positively impacted total and comparable sales by approximately +2.5% for the five-week December retail month. The 17-week fiscal year was not impacted.
For a deeper dive into the numbers check out this Seeking Alpha report: