If you’re asking how are used car prices determined, the short answer is supply and demand. Wholesale auction prices are the benchmark dealers watch, and mileage, vehicle type and the wider economy push them up or down.
This explainer belongs to the wider topic of automotive business.
| Item | Value |
|---|---|
| Manheim Used Vehicle Value Index, mid-August 2026 | 207.4 index points |
| Change in adjusted wholesale prices, first half of August versus July | Down 1.2% |
| Compact cars, year over year | Up 2.2% |
| EV Index, year over year | Up 5% |
| Wholesale days’ supply, Aug. 15 | 27.7 days |
These figures come from Cox Automotive’s mid-August 2026 Manheim report. They change with every release, so check the source before you rely on them.
Where does a used car’s price start?
Most retail price tags trace back to the wholesale market, where dealers buy cars at auction. The Manheim Used Vehicle Value Index tracks those prices in the US, and WardsAuto describes it as a single measure of used-vehicle wholesale price changes, weighted for a changing mix of segments and mileage.
The index is built to strip out noise. It adjusts for three things:
- The mix of vehicle segments being sold.
- The mileage of the cars in that mix.
- Normal seasonal swings in the market.
The same WardsAuto report says the index is calculated against a starting point where January 1997 equals 100. The September 2025 reading corresponded to an average used-vehicle value of $18,937 at auction, and the Manheim auction firm is itself a Cox Automotive company.
In Cox Automotive’s mid-August 2026 report, the index fell to 207.4, a 1.2% decrease from July. The official measure is reported on the fifth business day of each month, so a mid-month figure is a read on direction rather than a final number.
Why does supply matter so much?
Supply is the first lever. In its September 2025 coverage, WardsAuto quoted Cox Automotive’s Jeremy Robb saying wholesale values had continued to defy gravity a bit, as the industry suffered from lower used-vehicle inventory and increased demand for affordable vehicles.
The recent past shows how far supply can swing prices. According to the same WardsAuto report, the index moved like this:
- It averaged 152.9 over the 12 months before March 2020.
- It rose from 2020 on, prompted by the pandemic and new-vehicle shortages.
- It peaked at 257.7 in December 2021 and January 2022.
- It swung lower from September 2022 as new-vehicle supplies recovered, with a recent low of 196.1 in June 2024.
Dealer stock is the other half of the supply picture. Days’ supply estimates how long a given inventory would last at the current monthly sales rate if it were not replenished, per WardsAuto.
In the mid-August 2026 data, Cox Automotive put wholesale days’ supply at 27.7 days on Aug. 15, which was 2.6 days higher than a year earlier. New-car supply also feeds the used market through trade-ins, and if you want background on how carmakers team up, the guide on what does a joint venture mean in the auto industry is a useful companion.
How do demand, fuel prices and affordability change prices?
Demand follows what buyers can afford and what it costs to run a car. Cox Automotive noted that the national average gas price was $4.06 a gallon as of Aug. 17, up from roughly $3.14 a year earlier. Used EVs have benefited, with values up 5% year over year even as the pace of gains cooled.
Segments move at different speeds. In the same report, compact cars were the strongest performer at plus 2.2% year over year, while luxury had narrowed to a 0.7% gain. Midsize cars, SUVs and pickups were softer, which Cox Automotive linked to a rotation toward value.
New-car prices push on used-car prices too. A WardsAuto report published on Oct. 17, 2025 said Cox Automotive’s forecast put tariff-driven new-vehicle price increases at 4% to 6% for the following year, and as much as 8%. It added that higher new-car prices tend to drive shoppers to the used market, which in turn drives up used-vehicle prices.
Incentives matter as well. According to Trading Economics, Cox Automotive’s chief economist said the EV tax credit ended in September 2025, and used EV values then fell by 3% in October.
Fresh used-EV supply is a counterweight. Cox Automotive’s August 2026 commentary said off-lease EV supply continues to build and gives buyers more choice.
What do age, mileage and the calendar do to a price?
Older cars often hold their value better than newer ones when budgets are tight. Trading Economics reported that in the August 2026 data, younger vehicle cohorts saw greater depreciation, while nine- and 10-year-old vehicles stayed about six percentage points above their long-term averages.
Seasonality is the other quiet driver. Cox Automotive said the long-term average monthly move in non-adjusted values is typically an increase of 0.1% for the full month of August.
Some months are simply weaker. In its Trading Economics summary, Cox Automotive’s chief economist said October is generally the weakest month of the year.
How do the economy and recent swings fit in?
Broader conditions can overpower the seasonal pattern. Trading Economics reported that the index fell 1.1% month over month in September 2026, its third consecutive decline. Cox Automotive’s chief economist pointed to the conflict in the Middle East, diesel prices at record highs and rapidly climbing interest rates.
The same summary shows the index increased 0.5% in October 2026, the first rise in four months. A single reading does not make a trend, but it shows how quickly direction can change.
Pent-up demand also plays a role. In the October 2025 WardsAuto report, Cox Automotive’s chief economist said the market was constrained by supply and supported by substantial pent-up demand from nearly five years of constrained new-vehicle production.
Production depends on factories and the people who staff them. For background on the labour side of the industry, see the guide on what does the UAW do.
How does an auction price become a sticker price?
Dealers buy used cars from several places, and the source affects their costs. WardsAuto reported that publicly traded, franchised new-car dealer groups say auction cars are more expensive to buy for resale than trade-ins, purchases from their own service lanes or purchases off the street.
When you look at a listing, you can read it against the forces above. A simple way to do that:
- Compare cars of the same model, trim, age and mileage rather than headline prices.
- Check whether the vehicle’s segment is rising or falling in the latest wholesale data.
- Allow for the season, since some months are typically softer than others.
- Look at fuel prices and new-car prices, because both can shift shopper demand.
Wholesale data is a guide, not a price list. Retail asking prices also reflect each dealer’s own costs and condition of the specific car.
Frequently asked questions
Is the Manheim index the price I would pay at a dealer?
Show answer
No. It tracks wholesale prices at dealer-only auctions, according to WardsAuto. Retail prices add dealer costs and reflect the individual car.
How often is the index updated?
Show answer
Cox Automotive says the official measure is reported on the fifth business day of each month. It also publishes mid-month trend reports.
Why are EVs and compact cars gaining while SUVs and pickups fall?
Show answer
In the mid-August 2026 report, Cox Automotive tied the pattern to affordability and higher gas prices. Compact cars and EVs showed gains, while SUVs and pickups posted declines in wholesale prices against the previous year.
Do used car prices only go up?
Show answer
No. WardsAuto reported that a rise in the index followed 26 consecutive months of declines from a peak of 257.7 in January 2022.
