One in four Maryland borrowers owes more on the mortgage than the home is worth, according to new estimates.

One in four Maryland borrowers owes more on the mortgage than the home is worth, according to new estimates. (Getty Images)

One in four Maryland borrowers owed more on his or her home than it was worth at the start of this year, according to CoreLogic's newest estimates -- a lot of people, but not quite as many as the company thinks were underwater last year.

The real estate data firm put the tally at just over 335,000, down from 365,000 in the final three months of last year and the lowest figure since the summer of 2010.

Maryland ranked 9th among states with the highest levels of negative equity. Here's the top 10:

1. Nevada (61 percent of borrowers underwater)

2. Florida (45 percent)

3. Arizona (43 percent)

4. Georgia (37 percent)

5. Michigan (36 percent)

6. California (31 percent)

7. Illinois (28 percent)

8. Idaho (26 percent)

9. Maryland (25 percent)

10. Ohio (25 percent -- or, more exactly, 24.6 percent to Maryland's 24.8 percent)

You can see that negative equity remains huge, at least by CoreLogic's estimates, in the big bubble-and-bust states of Nevada, Florida and Arizona. At the other extreme are states like Alaska and North Dakota, both at about 6 percent.

CoreLogic believes the Baltimore metro area's negative-equity problem isn't as bad as the state's as a whole, estimating that just under 20 percent of borrowers in the city and its surrounding counties are underwater on their mortgages. That's about 126,000 in all, down from 136,000 during the last three months of last year.

For the sharp-eyed readers wondering why the figure for last quarter is higher than originally reported: CoreLogic changed the way it measures negative equity and updated past figures accordingly.

To estimate negative equity, you have to estimate a home's value first. (That's the part CoreLogic recently started doing differently.) You also need some way to get at what's owed -- whether by looking at the original loan balance and calculating the current amount by assuming payment on schedule, or by getting the actual balance.

So as you might expect, different companies have different best guesses. Real estate site Zillow estimates significantly higher negative equity across the country than CoreLogic does. It puts the underwater crowd in the Baltimore metro area at 31 percent at the beginning of this year. (Here's a map.)

Whatever its extent, negative equity is part of the reason buyers are seeing fewer options on the market. If you owe more than your home is worth, you can't sell -- not unless you bring a lot of cash to the settlement table or persuade your lender to approve a short sale.

Zillow wrote a paper about this phenomenon last month, subtitling it, "Why the Bottom Won't Be as Boring as We Expected."

"Our emerging hypothesis is that, instead of a long, flat bottom with price appreciation constrained by weak demand and elevated foreclosures, we might end up in an environment in which constrained supply (due to negative equity), together with robust demand from investors and first-time home buyers (not weighed down by negative equity), combine to create cycles of home value spikes followed by cooling periods," the company wrote.

What Zillow predicts: Not enough supply leads to higher prices, putting some underwater homeowners on the right side of the water line again, so they try to sell, "thus creating additional supply which tempers price appreciation."

Beyond that, there's the question of how many foreclosed homes will end up on the market and how fast. Hard stuff to predict -- accurately, anyway.

Got a housing news tip or experience to share? (Or just want to tell me something?) Email me at jhopkins@baltsun.com.