With the new car market set to deliver yet another record year, the used car supply network is on the verge of being choked.
"Supply is finally starting to outstrip demand," says WiseBuyer's editor Nic Barfield.
"The net result is further downward pressure on used values as the market tries to contend and adjust."
However, with so much stock slushing about, buyers can afford to be fussy about specification, colour, mileage and condition.
"There's no pleasure in compromise, and many motorists are now able to refuse second-best," adds Barfield.
Apart from top condition diesel engined superminis and family cars, used values are following an almost universal downward pattern.
Some Alfa, Fiat, Ford, Vauxhall, Nissan, Rover and Toyota models have shed up to 5% in recent weeks. Other heavy fallers include the Citroen Berlingo, Chrysler PT Cruiser, Peugeot's 306 and its replacement 307 and the old shaped Astra and Vectra duo from Vauxhall.