The problem is financing. Although government stimulus programs have spurred some home buying activity in the lower-priced market, would-be buyers of more expensive homes are strapped for credit. In most markets including Miami, Fannie Mae considers loans for homes above $420,000 or so to be “jumbo loans” that typically have higher interest rates. As sales of these homes are tight, home prices are hit–but prices are slower to budge.

“The high-end market is going down more than the overall market, but sellers in that market don’t necessarily see themselves as being different from other sellers,” says Miller. “So it’s causing the spread between the ask price and contract price to widen.”

In Orlando, the most overpriced large metro by our measures, homes are listed at 43% higher than what they sell for–a median $202,381.

“The demand in Orlando is really only for the least expensive properties,” says Mike Simonsen, CEO of Altos Research. “The market as a whole is overpriced, in that people are not buying on the high end, they’re buying on the entry level.”

Underwater Can Become Overpriced

But that doesn’t mean that cheaper homes are moving faster in all markets. The 23% of American homeowners who owe more on their homes than what they are worth would be unable to pay back their loans if they budged on their asking price. Most have no choice but to wait out the market even though values continue to drop.

“The people selling now are the people that have to sell,” says Miller. “Some sellers simply can’t adapt to the market. Maybe they bought a year ago and now they’re underwater. They will wait.”

Take Phoenix, the No. 12 most overpriced city, where 64% of homeowners are underwater, according to Zillow.com’s most recent Negative Equity Report. In that metro, homes are listed for 22% more than when they are sold, among the highest spread of all the cities we surveyed. Homeowners there simply can’t afford to drop their prices.

Some of the cities that were ranked most overpriced, like Chicago and San Antonio, had about average discrepancies between asking price and sale prices. By the strictest definition, they aren’t tremendously overpriced. But red flags fly for other, more subtle signs that their list prices may be out of whack.

In the largely healthy Chicago metro, rampant overbuilding in suburbs like Naperville has kept homes on the market for an average of six months–sellers aren’t pricing them to move fast. In San Antonio, 42% of homes have knocked asking prices down, a sign that the market disagrees with sellers on their initial price.

“There’s the straight list-to-absorbed price ratio, but a lot of metros are in this common range of about 115%,” says Simonsen. “So then you have to look at other factors, like how many homes have price reductions.”

Las Vegas, a market that has yet to emerge from the wreckage of the foreclosure crisis–one in every 68 homes was in foreclosure in October, according to RealtyTrac–is among the least overpriced large metro, a fact that may seem surprising. But although its housing market may take a long time to recover, homes are listed at a median $168,161, far lower than most large metros, suggesting that sellers have gotten pragmatic about pricing. And government initiatives like the first-time home buyer tax credit have spurred demand among budget buyers.

“In Las Vegas, it looks like homeowners are pricing homes to clear the market,” says Delores Conway, a visiting real estate economist at the Simon School at the University of Rochester. “And it’s because there’s financing available at the low end.”

Sellers don’t necessarily cling to optimistic asking prices out of stubbornness or cluelessness. Many can’t change their price–either because they’re trapped in a slow-moving high-end market, or because their homes are underwater, and selling at a loss isn’t an option.

“People don’t have negotiating power,” says Miller. “They’re not being greedy, but they just can’t be as flexible as the market demands.”

America’s Top 5 Most Overpriced Markets

1. Orlando-Kissimmee, FL Metro Area

2. Miami-Fort Lauderdale-Pompano Beach, FL Metro Area

3. Jacksonville, FL Metro Area

4. Baltimore-Towson, MD Metro Area

5. Chicago-Naperville-Joliet, IL-IN-WI Metro Area

Click here to see the full list of Where U.S. Homes are Most Overpriced.

Francesca Levy, Forbes.com