One indicator of wholesale used-vehicle prices fell again in October to mark five straight months of decreases.

Cox Automotive said Monday that its Manheim Used Vehicle Value Index — a measurement of wholesale used-vehicle prices Manheim puts together by tracking vehicles sold at its U.S. auctions and applying statistical analysis to those numbers — fell 2.2 percent in October from September. That follows a substantial decline in August and another decline in September.

Wholesale prices were down 10.6 percent at the end of October compared with the year-earlier period. Those numbers are adjusted for mix, mileage and seasonality. On a nonadjusted basis, the Manheim Index declined 2.1 percent from its September level, with prices down 9.3 percent year over year.

Retail prices fell 9 percent in October from September, and they were down 13 percent from the same time last year, according to Cox. Sales were down 32 percent compared with October 2019, the worst monthly comparison so far this year, Cox said.

Cox estimated used-vehicle retail supply was at 49 days at the end of October. That’s down from 52 days at the end of September, but up from 40 days at the end of October 2021. Wholesale supply ended October at 28 days, unchanged from the end of September but higher than 20 days at the end of October 2021.

Average wholesale prices for 3-year-old vehicles, the largest model year cohort at Manheim’s auctions, fell 2.2 percent in October from September.

Black Book’s Used Vehicle Retention Index also decreased, this time for the fourth-straight month.

The index dropped to 174.3 points in October, down 2.2 points or 1.2 percent from its September level, Black Book said Thursday. That was 3.3 percent below its October 2021 level but up 52 percent above March 2020, before the COVID-19 pandemic.

Black Book typically observes the highest decreases of wholesale prices in the fourth quarter, Black Book Chief Data Science Officer Alex Yurchenko said in a news release.

“This year will not be an exception, and we expect the declines in the next two months to match the historically high rates typically observed at the end of the year,” Yurchenko said. “We are also starting to see used retail prices decrease, although not as steeply as wholesale prices.”