Corelogic reports that 10.9 million, or 22.7 percent, of all residential properties with a mortgage were in negative equity at the end of the first quarter of 2011, down slightly from 11.1 million, or 23.1 percent, in the fourth quarter. An additional 2.4 million borrowers had less than five percent equity, referred to as near-negative equity, in the first quarter. Together, negative equity and near-negative equity mortgages accounted for 27.7 percent of all residential properties with a mortgage nationwide. In the fourth quarter, these two categories stood at 27.9 percent.  Negative equity, often referred to as "underwater" or "upside down," means that borrowers owe more on their mortgages than their homes are worth. Negative equity can occur because of a decline in value, an increase in mortgage debt or a combination of both.

"Many borrowers in negative equity are still able and willing to make their mortgage payments. Those in negative equity and impacted by an income shock of some kind, such as a job loss, divorce, or death, are much more likely to be at risk of foreclosure or a short sale.The current economic indicators point to slow yet positive economic growth, which will slowly reduce the risk of borrowers experiencing income shocks," said Mark Fleming, chief economist with CoreLogic. "Yet the existence of negative equity for the foreseeable future will weigh on the housing market recovery by holding back sale and refinance activity."

For a chart of underwater properties by State, click here.