Costco's Underlying Sales Growth Has Slowed 3 Months in a Row. Its September Report Comes Oct. 7. L...

Costco's Underlying Sales Growth Has Slowed 3 Months in a Row. Its September Report Comes Oct. 7. Leaving out gas prices and currency, Costco's comparable sales growth slowed from 8% in May to 5.4% in August. Costco posts sales for September, the first month of its fiscal 2027, after market close on Oct. 7.