During the real estate bubble, financial gurus touted home ownership as a solid investment.

As some of those investments have gone sour, some homeowners have done the once unthinkable: They've given up homes they can afford, but which have turned out to be bad investments.

"It's becoming more of a business decision," said Jon Maddux, co-founder of You Walk Away, LLC.

Based in Carlsbad, You Walk Away serves customers who have decided to walk away from mortgages. You Walk Away (www.youwalkaway.com, 877-878-9255) also partners with a company that advises customers who want to conduct "short sales," or sell their homes for less than the value of the mortgage.

Whether called "walking away" or "strategic default," this phenomenon unnerves investors and the federal government. They condemn strategic default as bad for the homeowner's credit, the neighborhood and the economy. Short sales don't get the same condemnation, because they are conducted with the lender's approval.

"We know from experience that foreclosures and vacancies drive down the property values of everyone else in the neighborhood. Thus, strategic defaulters, in effect, deplete the personal wealth of their neighbors," Don Bisenius, a Freddie Mac executive vice president, wrote on the government-backed lender's website in a May 3 article.

The opposing view holds that strategic defaulters are simply making rational economic decisions, just as wealthy investors and large companies do every day. The contract spells out the penalties for default. If you're willing to accept the consequences of breaking the contract, go for it.

Bad credit, at least for a time, is one of those consequences.

Walking away means foreclosure. Foreclosure means a big drop on your credit scores, which means you'll be paying higher interest rates on other debt, such as credit cards. You'll have to make prompt payments on your other bills for a considerable time to make up for that default.

On the positive side, you should be able to save money by renting. During the real estate boom, the monthly cost of mortgages in many markets such as San Diego County increased far more than did rents.

Those considering walking away should consider how long they are prepared to rent a similar home, the taxes and homeowners fees they'd save by defaulting, and how long it would take to recover their equity if they don't default, wrote Brent White, an economist at the University of Arizona, in a paper titled "Underwater and Not Walking Away."

White suggests that homeowners considering strategic default should shed their emotions and just add up the numbers and see if they make sense.

"There are, of course, costs to foreclosure other than temporarily poor credit. These include moving costs and possible transportation costs if one is required to live further from work or school," White wrote. "But again, these costs are minimal when compared to the savings of shedding a home that is hundreds of thousands of dollars underwater."

The feeling of a moral obligation to pay remains as strong as ever, and may be even getting stronger, White wrote in another paper published this month, "Walking Away: The Emotional Drivers of Strategic Default."

Three recent studies have found more than 80 percent of those surveyed opposed walking away on moral grounds, White said. Even if people have financial problems, paying the mortgage is considered a duty, not an option.

However, that rationale doesn't apply here, wrote Henry Blodget, a former research analyst barred from the securities industry because of fraud, in a Jan. 14 article.

"When you borrow money from a friend at no interest, for example, and you promise that friend that you will give him or her every penny back, THAT is a moral obligation to pay," Blodgett wrote. "In this case, your friend did not lend you money to make a profit. Your friend loaned you money to help you out ---- with no collateral or contract other than your promise to pay."

Call staff writer Bradley J. Fikes at 760-739-6641. Read his blogs at bizblogs.nctimes.com.