While most of America seemed content to stay put in 2008 (provided they could move), more than one in four people (27.7 percent) living in renter-occupied housing units lived in a different residence than they had occupied in 2007, according to the U.S. Census Bureau. And in owner-occupied housing units, the moving rate was 5.4 percent, making renters more than five times more likely to move. The reason for this volatility: the economy. As many industry execs fear, people are moving in with relatives and friends or sizing down.

“A lot of units have been emptying in my own market, and I don’t think it’s people moving up into homes,” says Nicholas Michael Ingle, director of capital markets for Hendricks & Partners, a broker based in Phoenix. “I would say it’s people seeking more affordable living situations, whether it’s people doubling up, moving home, or moving from As to Bs.”

While it’s likely that there have been some move-downs from Class A projects to Class B communities, another spin would be that dropping rents have moved Class B developments into the affordability range for some previous Class C renters who still have their jobs, adds Greg Willett, vice president of research and analysis for Carrollton, Texas-based M/PF YieldStar.