The Black Book Used Vehicle Retention Index is calculated using Black Book’s published Wholesale Average value on two- to six-year-old used vehicles, as percent of original typically-equipped MSRP. Black Book’s Wholesale Average is a benchmark value for used vehicles selling in the wholesale auctions with the vehicle quality in Average condition. The index is weighted based on used vehicle registration volume and adjusted for vehicle age, mileage, condition, and inflation (MSRP).

Aggregated from daily vehicle value updates, and captured throughout hundreds of wholesale physical and online auto auctions across the country, the Black Book Used Vehicle Retention Index represents data across all regions of the U.S. The Index is based on a comprehensive list of vehicles included in the Black Book wholesale database, and includes no bias toward any brand, auction or region, ensuring a more accurate reporting of the used vehicle market.