The drop in July sales was exaggerated by a retreat in oil prices - since reversed - and there was a quirk from Amazon bringing its "Prime Day" discount day forward to June this year.
But the reading chimes with a drop in consumer confidence in the University of Michigan's latest survey and has combined with last week's subdued inflation reports to rein in Federal Reserve rate hike expectations for September.
The reheating of oil prices in recent weeks amid the Iran war standoff might shift some of that picture before the Fed meets next month, but the rate relief for now has been enough to keep Wall Street stock indexes pushing to record highs.
With no breakthrough on the Iran impasse over the weekend, President Donald Trump told Americans that slightly more expensive gas was a price worth paying for seeing the conflict out.
As to the Fed story, we're due to get minutes of July's split policy meeting on Wednesday, and an industrial production number tomorrow.
Elsewhere, Japan's 10-year government borrowing rates hit a three-decade high on Monday, even as Japanese GDP came in well below forecasts with an annualized rise of 1.1% in the second quarter.
While sputtering growth, due in part to energy prices, may complicate Bank of Japan rate rise plans, the yen held firm on Monday as a broadly weaker dollar dominated on the Fed view.