They swarmed the distressed housing market, buying thousands of foreclosed properties and pushing prices higher faster than anyone expected. Now investors are pulling back, dissuaded by the higher prices they themselves brought about.

"Perhaps the numbers aren't working out," said Lawrence Yun, chief economist of the National Association of Realtors, which reported that just 15 percent of June sales were by investors. That is the lowest share since the association began tracking this cohort in October 2008.