Even as home prices climb, four out of 10 homeowners here still owe more on mortgages than their homes are worth, making Tampa Bay the most underwater area in the country.

Still, the local situation is improving, with the share of home loans that are underwater dropping from 48 percent to 41 percent over the last year, new CoreLogic data show.

About 255,000 homeowners here are underwater because they took on debt during the housing boom with inflated home purchases or home equity loans, or saw their home values plunge during the bust.

About 38 percent of Florida's 4 million homes with mortgages are underwater, the second highest rate behind Nevada. The Miami area had the second highest rate of underwater homeowners, at 40 percent.

But as home prices have risen, the share of underwater home loans here has fallen 10 percentage points since late 2010, when more than 340,000 were underwater.

The numbers released Wednesday come from the first three months of the year, and price gains in the months since have likely improved the situation.

Rising home values could free more homeowners to sell, easing tight housing supplies and smoothing out big gains in home prices.

"The impressive home price gains of 2012 and the beginning of 2013 have had a big impact on the distribution of residential home equity," CoreLogic chief economist Mark Fleming said in a statement.

"We expect that the pent-up supply that falling negative equity releases will moderate price gains in many of the fast-appreciating markets this spring."

Drew Harwell can be reached at dharwell@tampabay.com or (727) 893-8252.