Prices for new vehicles are falling at the fastest rate ever recorded, a team of analysts said Thursday, squeezing automakers’ profit margins at a time of slumping sales but setting the stage for a sales rebound once the economy improves.

In a research report, JPMorgan analysts said the average price of a new vehicle in the second quarter fell 2.3 percent from a year earlier to $25,632, citing government data. That’s the steepest drop recorded in the bank’s 41-year-old survey, the report said.