There are more factors adding to the downtrodden U.S. housing markets and related shares and exchange traded funds (ETFs) than one may think, but there’s also more and more good news appearing, too.

The most recent good news first: New housing starts and permits have risen for the second straight month in June. Starts climbed 3.6%, reports Reuters.

And now the bad news.

According to new research from the University of Chicago’s Booth School of Business and Northwestern University’s Kellogg School of Management, a study found that 26% of foreclosures are actually calculated and strategic, thanks to “negative equity.”

The decision to bail out of loans by owners who actually have the money to make the payments but can’t handle the negative equity they’re carrying caused by local property value declines are causing people to simply mail their house keys back tot he lender, reports Kenneth Harney for The Los Angeles Times. In certain parts of California and Nevada, more than half of all households have negative equity right now.

Real estate investment trusts (REITS) also face potholes ahead.

• SPDR S&P Homebuilders (XHB): up 3.5% year-to-date

• iShares Dow Jones US Home Construction (ITB): up 4.6% year-to-date

For more stories about real estate, visit our real estate category.

Tags: Asset Class ETFs, Homebuilders, ITB, Real Estate, Sector ETFs, XHB