When it comes to weak home sales data, the blame usually falls on skittish consumers, too afraid to commit to such a big purchase in a still-shaky economic environment.
Not this time.
Sales of previously owned homes fell 1.5 percent in May, according to the National Association of Realtors, but this time economists blamed a tightening supply of homes for sale.
"The slight pullback in monthly home sales is more likely due to supply constraints rather than softening demand," said Lawrence Yun, NAR chief economist, in a statement. "The normal seasonal upturn in inventory did not occur this spring."
At the current sales pace, total housing inventory fell to just under 2.5 million homes, according to NAR, more than 20 percent below levels last year and down from a record high 4 million unsold properties recorded in July 2007.
Markets in the West have been particularly crippled by a lack of homes for sale, with Realtors in those states clamoring for faster foreclosure processing to get more properties on the market sooner.
"They have more buyers than available property," Yun added, a phenomenon that has fueled bidding wars and super-quick sales in some of the nation's hottest markets.
But even with supply issues crimping sales, numbers were still almost 10 percent above levels seen a year ago, making May the 11th consecutive month of year-over-year gains. Still, economists foresee a continued tightening of supply in coming months.
[Read: Housing Starts Slump in May.]
"The trend in our view will remain tilted toward a gradual receding in the stock of properties as demand for housing continues to firm," Michael Gapen of Barclays wrote in a note to clients.
More evidence that home prices are stabilizing was also embedded in the NAR report. Median existing-home prices rose almost 8 percent to about $183,000 in May, marking the third consecutive month of year-over-year gains. Economists attribute much of the improvement in prices to fewer distressed home sales, which tend to bring deep discounts.
Investors also made up a smaller proportion of sales in May, giving credence to the notion that more traditional buyers are re-entering the market.
Meg Handley is a business reporter for U.S. News & World Report. You can reach her at email@example.com and follow her on Twitter.