Values of used convertible cars failed to climb to their usual seasonal highs this summer, and could fall below the seasonal norm during the coming months, according to EurotaxGlass’s, publisher of Glass’s Guide to Used Car Values.

“This has been the worst year in living memory for used convertible values,” said Adrian Rushmore, managing editor at EurotaxGlass’s.

“In previous years, asking prices for most second-hand convertibles increased during the spring and early summer in response to an uplift in consumer demand. For example, from May to July last year convertible values rose by up to 10%. By contrast, a combination of factors has led values to remain static at best during the peak buying months of 2007.”

Rushmore cites a number of reasons for 2007’s lacklustre convertible market. “Following an all-time high of 116,000 new convertible registrations in 2004 - almost 20% up on 2003 - a substantial number of additional used three-year-old examples will have reached the used market during 2007. These additional volumes will have played a significant role in subduing prices of second-hand models.”

“In addition, since 2003 sales of new convertibles have consistently exceeded 100,000 units, leading to increased volumes of younger cars being available for sale, again keeping prices in check.”

This situation has developed against the backdrop of growing numbers of new drop-top models being offered by manufacturers: in 2003 there were 377 convertible models available new, and this number increased to 531 by 2006, a rise of over 40%.

The final issue affecting convertible values has been the poor weather experienced throughout the UK this summer, which has done nothing to raise the level of demand in this segment.

“Dealers report that retail demand for second-hand convertibles has been much the same as in recent years,” adds Rushmore. “But the increase in supply of cars over the last few years has meant that buyers of these models now have a greater choice than ever. Consequently we have not seen the seasonal price hikes which have become an established feature of the market.

“Looking ahead, we do not expect values to drop away to the extent they have previously done at the end of summer. That said, they will still fall and could reach new lows in the autumn, though we do not predict a price crash. What seems clear is that price rises of up to 10 per cent during the spring and early summer are now a thing of the past,” Rushmore said.