LAWRENCEVILLE, Ga. -

Just like the temperatures outside, Black Book is expecting used-vehicle values to cool for the remainder of the year.

On Tuesday, Black Book released its Used Vehicle Retention Index for September, which came in at 115.9. The reading marked a 0.6% decrease from August, when it was 116.6.

“The used market held up pretty well during summer when traditionally, the values have declined,” Black Book executive vice president of operations Anil Goyal said in a news release.

“However, we are now starting to see that the market strength is waning. We expect the index to continue to drop in the remaining months of the year,” Goyal continued.

The Black Book Used Vehicle Retention Index is calculated using its published wholesale average value on 2- to 6-year-old used vehicles as a percent of original typically-equipped MSRP. It is weighted based on registration volume and adjusted for seasonality, vehicle age, mileage and condition.

The index dates to January 2005 when Black Book published a benchmark index value of 100.0 for the market. During 2008, the index dropped by 14.1% while during 2016, the index fell by just 6.4%.

During 2011, the index rose strongly from 113.3 to 123.0 by the end of the year as the economy picked up steam and used vehicle values rose higher. It continued to remain relatively stable, rising slightly until May of 2014 when it hit a peak of 128.1.

 To obtain a copy of the latest Black Book Wholesale Value Index, go to this website.