Costco Wholesale Corporation net sales were $5.14 billion for the month of May, the four weeks ended June 3, 2007, an increase of 11% from $4.63 billion in the same four-week period last year. Comps increased 7% for the month.

For the first forty weeks of its reporting period ended June 3, 2007, the Company reported net sales of $47.96 billion, an increase of 9 percent from $44.10 billion during the similar 40-week period of the prior year. The fiscal 2007 year-to-date net sales results include the $452 million adjustment to the sales returns reserve previously reported in the fiscal 2007 second and third quarter results. Excluding the sales returns reserve adjustment, net sales for the 40-week year-to-date period were $48.41 billion, representing a 10% increase over the prior year.

Comparable sales for the 4-week retail-reporting month of May and the 40-week retail-reporting period of September through May are as follows:

                                  4 Weeks         40 Weeks
                                 ---------       ----------
               US                    7%              5%
               International         7%              8%

               Total Company         7%              5%
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