Like a roller coaster at a state fair, wholesale vehicle values descended rapidly in October — and the declines were “faster than usual,” according to Black Book.

To use another seasonal metaphor to describe the fall, used-car deprecation was “a little spooky” last month, says Cox Automotive.

Both firms have released their observations on October’s wholesale vehicle market, with both pointing to a drop in values.

The Used Vehicle Retention Index from Black Book came in at 142.1 for October, which is down 1.6% month-over-month and 3.4% year-over-year.

“The market saw depreciation pick up pace in October,” said Laura Wehunt, Black Book vice president of data & analytics, in an analysis. “It’s normal for most of the year’s depreciation to happen in the fourth quarter, but this time the declines came faster than usual.

“By the end of the month, we were seeing weekly depreciation nearly double what’s typical for this time of year. September’s new-car sales were strong, especially for electric vehicles, as buyers rushed to take advantage of tax credits before they expired,” continued Wehunt, who is among the experts set to appear during Used Car Week that begins on Nov. 17 in Las Vegas. “But once those incentives ended and inflation continued to squeeze consumers, demand slowed in October, putting added pressure on the used market.”

Meanwhile, Cox Automotive’s Manheim Used Vehicle Value Index came in at 202.9, which is down 2.0% month-over-month drop, when adjusted for mix, mileage and seasonality, and steady with a year ago.

Unadjusted, prices fell 3.7% month-over-month and were up 0.2% from October 2024, “giving back some of the strength observed throughout most of this year,” Cox said.

“Trends get a little spooky in October for the wholesale markets, typically showing us the highest levels of depreciation in the year — and this year was no exception,” Cox Automotive deputy chief economist Jeremy Robb said in an analysis.

“It’s typical to see higher declines for values in October, as dealers slow down ahead of winter, and the new model year mix grows in retail inventory — both of which can put pressure on values,” Robb said. “At the end of October, roughly 49% of all new vehicles on dealers’ lots were MY26s, and that’s higher than we usually see. When coupled with wholesale values that had declined very little so far this year, you can get more volatility.”

Throughout the month, used-vehicle retail sales gained momentum, however, leading to tighter inventory, Robb said. This resulted in less depreciation than usual by the month’s last week, he said.

“With tighter days’ supply and solid demand, we may see lower depreciation trends for the rest of Q4,” Robb said. “Consumers should see higher tax refunds next year and as more dealers catch wind of that, we could expect more demand at wholesale and retail earlier than usual next year.”