The drop was less than expected. Forecasts had pegged the decrease as likely to come in at 0.3 percent to 0.6 percent. Excluding auto sales, which dropped 2.9 percent, sales rose 0.3 percent, Commerce said.
Total sales settled down to $387.1 billion, off from the previous month, but 7.7 percent higher than May 2010.
From a year ago, sales at gasoline stations rose 22.3 percent, while non-store retail sales, which includes catalogs and Internet commerce, rose 15.9 percent in the same 12 months.