Average used-car values fell £18 to £5,784 in July as demand remained largely stable, with a relatively varied mixture of cars available for sale, according to British Car Auctions.
Year-on-year values fell for the third consecutive month, down £244 - the largest drop seen this year - compared with unprecedented highs witnessed 12 months ago.
However, values are ahead of those recorded two years ago, figures byBritish Car Auctions show.
Average fleet values dropped £276 or 3.7% last month, while premium fleet values were down 3.8%.
However, nearly-new values climbed 6.6% to £20,039 in July, according to figures.
BCA communications director Tony Gannon said: "Prices have continued to be under some pressure in July, especially in the fleet and lease sector, but sales volumes have held up well in the month, and demand is there for vehicles that are valued in line with their condition and market expectations.
"Although we have not experienced seasonal patterns in the market for some time, we are seeing them now and should expect these to continue over the rest of this year."
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