April’s U.S. new-vehicle sales pace, on track to end at a four-year high for the month, nevertheless reflects a cooling off from the hot sales surge of March.

Cox Automotive points to diminishing inventory after the unusually robust spring sales spurred by consumers getting ahead of any U.S. trade tariff affects on vehicle prices. Ironically, the tighter supply likely led to price increases, it said.

Cox forecasts the seasonally adjusted annual rate for April to hit 16.4 million, up by 400,000 units year-over-year, though that’s down substantially from the March 17.8 million SAAR. 

It sees April sales hitting 1.4 million units, up about 5% year-over-year but off March’s result by 12%, though April has the same number of selling days as March and one more than last April.

Though the month started strongly, Cox said, sales started to dwindle in the second half.

Senior Economist for the company, Charlie Chesbrough, acknowledged that foreseeing market effects from tariffs is an uncertain proposition.

“Forecasting sales in this volatile market is quite challenging, and that is what we have right now, a market being steered by headlines coming from the White House,” he said. 

“With economic concerns rising and consumer confidence declining, the outlook for new auto sales from here is more troubling. If current policy holds, prices in the new-vehicle market will be noticeably higher in the coming months as more costly products replace pre-tariff inventory.”

New-vehicle inventory fell throughout March and April to about 60 days’ supply by mid-month, down from 89 days at the beginning of March, Cox said.

LEARN MORE: Tariff Impact Forecast