Recent history suggests American automobile sales indicate subsequent moves in U.S. equities.

Declines in 2011 and 2012 were followed by a retreat in the S&P 500 index, and gains in the fall of 2015 came before a market rally.

While the relationship isn’t exact, and correlation doesn’t equal causation, the surprising slump in vehicle sales last month comes just as investors are questioning how much to believe off-the-charts surveys of American confidence levels.

The retreat in the auto sector reported Monday mirrors lackluster broader consumer spending data released Friday. Both readings fly in the face of the two most-followed gauges of consumer sentiment, now at 17- and 11-year highs. It also contrasts with an index of optimism among small businesses — local car dealers among them — holding near levels unseen since the mid-2000s.

There’s more hard data coming this week to put the soft data to the test —