Maggie Medved was stuck with her Phoenix house for two years after the market crash wiped out the equity in the property. Last year, as prices in the area rose by the most in the U.S., she and her partner were finally able to sell the 3-bedroom 1950’s style home and move to a larger place.

“We were counting the days for when we could move,” said Medved, 40, who trains employees for weight loss company Jenny Craig Inc. “We definitely knew it was a waiting game because it would’ve been financial suicide if we had sold earlier.”

Medved was among the 12 million borrowers in the U.S. who at the peak of the real-estate downturn owed more on their mortgages than their houses were worth, blocking them from moving or saving money by taking advantage of the lowest borrowing costs on record to refinance. As prices recovered, the number of underwater borrowers fell by almost 4 million last year to 7 million, according to JPMorgan Chase & Co., and could drop to 4 million within 2 years.

The housing market is rebounding faster than anyone thought possible, according to Blackstone Group LP’s global head of real estate Jonathan Gray, as the Federal Reserve buys mortgage bonds to keep rates near record lows and investors sop up a diminishing supply of properties for sale. Housing construction could boost U.S. gross domestic product by 0.4 percentage point and home price appreciation may add another 0.2 percentage point, Bank of America Corp.’s senior economist Michelle Meyer forecasts.

‘Appreciating Asset’

“It supports household wealth, consumer confidence and can generate greater credit creation,” Meyer said. “If prices are rising, homeowners believe that they will once again have an appreciating asset. It’s a very big change in how they think about their wealth and their balance sheets.”

Medved’s Phoenix home was on the market for two days before it sold for $85,000, just shy of the price paid in 1998. She and her partner Wendy Thomas bought a larger property with a pool for $210,000 in Glendale, about 10 minutes away.

“We’d outgrown the house and the neighborhood took a turn we didn’t like,” Medved said. “Almost 12 years later we were in the hole $30,000. We couldn’t take that much of a loss and needed to stay regardless of what the neighborhood had become.”

Arizona’s capital city is leading the U.S. in price appreciation, surging 22 percent in the 12 months through October, according to an S&P/Case-Shiller index, which had the biggest year-over-year advance since May 2010. Eighteen of the 20 cities in the index showed increases from a year earlier.

Even with the gains, Phoenix prices were down about 45 percent through November from their 2006 peak, according to Zillow Inc. Nationally, prices peaked in May 2007, according to the real-estate website, and are down 19 percent.