The housing market continues to deteriorate. Thursday's report on May pending home sales was down 30% from the prior month and nearly 16% vs. a year ago. The market weakness spans the country. Sales in the Northeast, Midwest and South fell more than 30%, the bright spot, the West, only fell 21%. The news comes after last week's record low new home sales in May, which plummeted nearly 33%. Experts say the expiration of the new homebuyer tax credit is to blame for the sudden market softness. Unfortunately, the market could get worse and prices could fall further, says Richard Suttmeier of ValuEngine.com. High unemployment and struggling community banks are two main causes. Saddled with bad housing and construction loans, local banks will continue to restrict lending. Plus, the failure of the Obama administration's mortgage modification program means a steady flow of short sales. People are going to be surprised when they see there have been short sales, which negatively impact appraisals in the local community, says Suttmeier. How low can prices go? Using the S&P/Case-Shiller index as his guide, Suttmeier suggests homes across the country could lose half their value. If it gets back, like stocks, back to the 1999-2000 levels, thats another 50% down in home prices, he says.