House prices may still have a long way to fall.

More on the Case-Shiller numbers from the International Herald Tribune

Across much of the nation, home values are dropping — even those backed by solid mortgages — and banks are repossessing more every day. Most experts say the dive won't hit bottom for another year and only after excess inventory is sharply reduced and credit markets improve.

More government intervention may be needed, too, if the free market system doesn't work quick enough.

"The housing value crisis is spreading and deepening," said David Abromowitz, a senior fellow at the Center for American Progress. "It has gone way beyond subprime borrowers stretched too far with bad loans and now has clearly extended into the housing markets more broadly."

U.S. home prices dropped 8.9 percent in the final quarter of 2007 compared with a year ago, according to the Standard & Poor's/Case-Shiller home price index released Tuesday. That marked the steepest decline in the index's 20-year history.