Used-vehicle retention values fell 1.2% in August

The August retention index moved lower

Black Book's September 3 release puts its seasonally adjusted U.S. Used Vehicle Retention Index at 144.3 for August 2026. That is 1.7 points, or 1.2%, below July's 146.0 reading and 1.5% below the August 2025 reading of 146.5.

The company says the index declined for a third consecutive month while used-vehicle values remained roughly 30% above 2019. Both statements describe Black Book's proprietary wholesale benchmark, not the price of every used vehicle or a government inflation measure.

What the index measures

Black Book calculates the index from its published Wholesale Average values for two- to six-year-old vehicles as a percentage of original typically equipped MSRP. It weights the data by registration volume and adjusts for seasonality, age, mileage, and condition.

That construction differs from Cox Automotive's Manheim Used Vehicle Value Index, which MyFavi currently covers through its separate mid-August release. It also differs from the Bureau of Labor Statistics used-cars-and-trucks consumer index. The benchmarks can move differently because they use different data, populations, timing, and methods.

What sellers can take from the decline

A lower national retention index suggests softer wholesale conditions across the vehicles represented in Black Book's data, but it does not dictate a specific trade-in or private-sale value. Local supply, model demand, mileage, condition, title history, equipment, and maintenance records still matter.

• Check several current local listings and valuation sources for the same year, trim, mileage, and condition.
• Separate a dealer's trade-in offer from the negotiated price of the replacement vehicle.
• Document service history, equipment, tires, cosmetic condition, and known defects before requesting offers.

What buyers can take from the index

The monthly decline is a reason to refresh comparisons, not proof that every asking price should fall 1.2%. Retail sellers may acquire inventory at different times and have different reconditioning, transport, and carrying costs.

• Compare the out-the-door price across similar vehicles instead of relying on the national index alone.
• Review the title and vehicle history, then arrange an independent pre-purchase inspection.
• Compare APR, term, amount financed, and total payments separately from the vehicle price.