Mid-size SUVs from the 2010 to 2014 model years recorded the highest depreciation in August, slipping 3 percent from July to $18,650, while compact pickups increased in value during the month, according to Black Book.

Overall, vehicles depreciated 1.6 percent in August to $15,969 and 12 percent year-over-year. Cars depreciated 2.1 percent, while trucks depreciated 1.3 percent.

Mid-size SUVs such as the Audi Q7, Buick Enclave, GMC Acadia, Chevrolet Traverse and Mazda CX-9 also fell 15.4 percent year-over-year. Other categories that slumped in August included full-size cars (down 2.6 percent), prestige luxury cars (2.5 percent), entry-level cars (2.4 percent), sporty cars (2.3 percent), and entry mid-size cars (2.3 percent).

Compact pickups such as the Toyota Tacoma increased 0.4 percent in value to $19,524 and showed the slightest depreciation year-over-year of 3.1 percent. The arrival of the redesigned 2016 Tacoma later this month doesn't appear to have affected the residual value of these trucks. Full-size SUVs also recorded a positive month, increasing 0.2 percent to $26,670.

Other truck categories showed relative strength and depreciated only slightly, including full-size passenger vans (down 0.4 percent), passenger minivans (0.5 percent), and full-size pickups (0.8 percent).