Average auction prices for Volkswagen's beleaguered diesel vehicles have dropped nearly 16 percent in the four weeks since the emissions issue, according to Kelley Blue Book.
Also, the car valuation and information site said that new-car shopping activity for the vehicles have dropped on KBB.com by 2.4 percent.
In addition, the average auction price for the brand's gasoline-powered vehicles declined by 2.9 percent, Kelley said.
Tim Fleming, of Kelley Blue Book, said that some auctions are still holding off on selling the affected Volkswagen inventory.
"While Volkswagen diesel auction prices are in decline, we could see larger fluctuations depending on how this inventory is handled," he said in a statement.