According to the National Association of Motor Auctions (NAMA) average selling values decreased -0.6% from £5,392 to £5,361 in July.
Its monthly car auction data report also revealed that first time conversion rates increased by 3.8% to 79.2% from June - the rate was also up 3.2% on July 2016.
Louise Wallis, Head of NAMA commented, “It is positive to see that auction activity strengthened further in July.
“First time conversion rates were just below where they were in January at 79.2% - coming in significantly better than the same period last year.
“Increased demand from trade buyers led to hammer prices bouncing back from where they were over the last quarter, with strong prices achieved for stock in the best conditions.
“We anticipate the market to remain stable and look forward to seeing what the coming months bring.”
The report also showed that average mileage went up by 1.3% to 64,916.