STAMFORD, Conn. -

Used-vehicle values in May added to the string of historically lofty prices, according to RVI Group, but the used market is likely poised for slowdown.

RVI is forecasting a 2.2-percent drop in used prices from current levels for the rest of 2011, officials said in the latest RVI Risk Outlook.

This would be a change from what has been the dominant trend through 2010 and 2011.

For every month of 2010 and each of the first five months of this year, wholesale values have moved forward.

In May, specifically, the RVI Used Car Price Index was 1.402, up 1.5 percent month-over-month and up 16.5 percent year-over-year.

In an interview with Auto Remarketing on Monday, RVI’s Wayne Westring attributed the surge to two factors, the first being the decline in used supply. He stressed that another “big part” has been new-vehicle prices, which were up 1.1 percent month-over-month in May and 3.5 percent year-over-year.

“They basically raise the ceiling for used-car prices,” he explained to Auto Remarketing. “Those two things are contributing to used-car prices going up.”

But this surge isn’t likely to last. The full-year used index level for 2011 is expected to be down 1.7 percent from where it is right now, according to RVI.

Westring boiled this down to a number of factors.

For starters, the economy hasn’t recovered like it was initially expected to. The consumer outlook is low and unemployment is high.

“It’s not as healthy as we thought it would be right now,” he said of the economy.

Moreover, gas prices have skyrocketed as well. While consumers might be used to this because of the gas-price spike of 2008, they may not have been ready for the costs in other segments to go up like they have, Westring noted.

“They’re being squeezed by other prices going up,” Westring said, giving food prices as an example. “Every other market seems to be going up because of gas prices.

Breaking down RVI’s analysis by segment, small pickups (down 0.7 percent) were the only segment listed by RVI to show a month-over-month decrease in May. Prices in all other segments climbed, with sub-compacts (up 4.2 percent) showing the largest increase.

Each of the segments saw their values increase year-over-year, with subcompacts (up 43.4 percent), compacts (up 30.4 percent) and sports cars (up 26.5 percent) leading the charge.

Other segments to increase above the industry average of 16.5 percent were small and midsize sedans (each up 24.8 percent), sporty coupes (up 20.8 percent), full-size sedans (up 20.6 percent) and small pickups (up 18.4 percent).

Full-size pickups (up 2.6 percent) and full-size SUVs (up 2.8 percent) were the only segments not to see double-digit price gains on a year-over-year basis.