Costco Wholesale Corporation reported sales results five weeks and seventeen weeks ended December 30, 2012. The company reported net sales of $11.21 billion for the month of December; the five weeks ended December 30, 2012, an increase of 12% from $10.05 billion during the similar five-week period last year. This year's five-week period contained an extra day compared to last year, due to the timing of the New Year's holiday, which positively impacted total and comparable sales by approximately 2%.

For the first seventeen weeks of its fiscal year ended December 30, 2012, the company reported net sales of $34.42 billion, an increase of 9% from $31.68 billion during the similar period last year.