The percentage of homes in "negative equity," in which the owner owes more than the house is worth, was mixed in Northern Colorado in the fourth quarter, according to data released by CoreLogic.

In Greeley, 35.6 percent of all residential properties with a mortgage were in negative equity territory in the  quarter, down from 38.1 percent in the third quarter.

In the Fort Collins-Loveland metropolitan statistical area, the percentage of homes under water increased from 7.6 percent to 8 percent.

Statewide, 21 percent of homes are under water in quarter, while 22.8 percent of all residential properties with a mortgage were in negative equity across the nation, compared with 22.1 percent in the third quarter of 2011.

"The negative equity share is back to the same level as Q3 2009, which is when we began reporting negative equity using this methodology," said Mark Fleming, chief economist for CoreLogic. "The high level of negative equity and the inability to pay is the 'double trigger' of default, and the reason we have such a significant foreclosure pipeline."