Apartment vacancy rates for the second quarter of 2007 varied widely depending on the specific submarket and data source, said the National Multi Housing Council in its August Market Trends report. The U.S. Census Bureau reported a 10.1 percent vacancy rate for all rental apartments compared to a 4.9 percent rate reported by M/PF Yieldstar for investment-grade properties. The Census data represents a 0.6 percentage point improvement from the first quarter, while Yieldstar's results show a 0.1 percentage point decline since the first quarter of 2007.

Meanwhile, the National Association of Realtors reported last month that—despite anecdotal evidence of the impact of both the single-family and condo shadow markets—multifamily vacancy rates are likely to stay steady at 5.9 percent this year and ease to 5.6 percent by the end of 2008. NAR expects average rents to increase 2.9 percent this year and 3.8 percent in 2008, down slightly from a 4.1 percent increase in 2006.

According to NAR, the areas with the lowest apartment vacancy rates (2.7 percent or less) include Northern New Jersey, Salt Lake City, Philadelphia, Pittsburgh, Los Angeles, Minneapolis, and Nashville.