High used-vehicle prices at dealer-only auctions continue to “defy gravity a bit” due to lower inventory and demand for affordable vehicles, according to auction firm Manheim, a Cox Automotive company.

The rate of increase is smaller than it was a few years ago, but the net effect is that the publicly traded, franchised new-car dealer groups report that auction cars are more expensive to purchase for resale compared with trade-ins, purchases from their own service lanes or purchases off the street. 

The just-published Manheim Used Vehicle Value Index for August is 207.4. That’s an increase of 1.7% vs. a year ago but even with July 2025. The August Manheim Index corresponds to a seasonally adjusted, average used-vehicle value of $18,974 at auction.

More Stable – Relatively

The Manheim Index is a single measure designed to track used-vehicle wholesale price changes – weighted for a changing mix of product segments and mileage – and seasonally adjusted. The index is calculated relative to a starting point, where January 1997 equals 100.

“Changes in wholesale values have continued to defy gravity a bit this year, as the industry suffers from lower used-vehicle inventory levels and increased demand from consumers for affordable vehicles,” Jeremy Robb, deputy chief economist for Cox Automotive, says in a news release.

The Manheim index has been stabilizing most of this year compared with a roughly two-year increase starting in 2020, which was prompted by the pandemic and new-vehicle shortages.

That was followed by a roughly two-year swing lower, starting in September 2022, as new-vehicle supplies recovered hand-in-hand with increased trade-in volumes.

The big swings did not cancel each other out, however, and the index remains considerably higher than before the pandemic. For the 12 months before March 2020, the index average was 152.9.

By comparison, the latest peak – in December 2021 and January 2022 – is 257.7. The recent low is 196.1, in June 2024.

High Demand, Low Supply

Based on data from Cox Automotive’s vAuto, combined used-vehicle sales at new-car dealerships and independent used-car dealerships were up in August by an estimated 9% vs. August 2024.

Data from vAuto also estimates a 42-day supply of used autos at new- and used-car dealerships, down from 46 days at the end of July and 44 days in August 2024.

Days’ supply estimates how long a given inventory would last at the current monthly sales rate if it were not replenished.