Used vehicle values from the 2010 to 2014 model years fell 0.5% in May from April levels with cars showing a slightly higher depreciation rate than trucks, according to Black Book.

The average price of commercial vehicle transactions of cars fell 1% to $11,326, while trucks fell 0.2% to $18,001. Overall sales values averaged $14,432, which was a 16.6% decline in value from a year ago.

Four vehicle categories increased in value from April, including sub-compact luxury CUVs (0.3% to $16,801), sporty cars (0.2% to $14,050), full-size pickups (0.1% to $22,149), and full-size cars (0.1% to $12,940). Minivans were flat at $15,206.

Meanwhile, six vehicle categories declined at least 1% from April, including sub-compact cars (2.4% to $6,683), compact vans (2.2% to $10,017), compact cars (1.6% to $8,070), luxury cars (1.6% to $20,153), prestige luxury cars (1.5% to $35,160), and mid-size cars ($9,496).

"Now that summer is quickly approaching, it is not surprising to see in-demand segments such as sporty cars and sub-compact luxury utilities see better demand and retention at the auctions currently," said Anil Goyal, senior vice president of automotive valuation and analytics. "We anticipate that this summer will see its usual pattern of higher depreciation settling in for most cars and even slightly higher patterns for certain truck segments due to higher volume."