WASHINGTON — Signs are emerging that the U.S. housing market's long slump is likely to fester through the summer, and the real estate market might not recover for at least another year.

The latest report, the National Association of Realtors' pending home sales index, slipped 4.7 percent in May to the third-lowest reading on record. The decline "suggests we are not out of the woods by any means," said Lawrence Yun, chief economist for the trade group.

The bad news came as the regulator for Fannie Mae and Freddie Mac tried to reassure investors that an accounting rule change wouldn't force the government-chartered mortgage finance companies to raise tens of billions of dollars in capital to offset losses.

With more negative data about the housing market continuing to emerge as the economy weakens and job losses accelerate, economists are reluctant to say the worst is over.

"Even if housing market activity does manage to bottom out later this year, it is likely that any recovery would be exceedingly slow," Jeffrey Lacker, president of the Federal Reserve Bank of Richmond, said in a speech in Washington.

While home sales are likely to fall to their lowest point late this year or early next year, any recovery is likely to be weak through at least 2010, said Mark Vitner, senior economist with Wachovia Corp.

Meanwhile, prices shouldn't hit bottom for another year at the earliest, Vitner said, since the housing market is glutted with unsold new homes and foreclosed properties.

Making matters worse, rates on 30-year mortgages have been above 6 percent since late May, leading to a steep decline in new applications.

The NAR's seasonally adjusted index of pending sales for existing homes fell 4.7 percent to 84.7 from an upwardly revised April reading of 88.9. The index was down 14 percent from May 2007. Sales are considered pending when the seller has accepted an offer but the deal has not closed. Wall Street economists surveyed by Thomson/IFR had predicted a reading of 87.

The index, which sank to a record low of 83 in March, stood at 98.5 in May 2007. A reading of 100 is equal to the average level of sales activity in 2001, when the index was started.

Pending sales fell around the U.S., sinking the most in the South and the least in the West.

Despite the negative numbers, "the worst of the hemorrhaging is behind us" and a modest recovery is likely to take shape next year, said Bernard Baumohl, managing director of Economic Outlook Group.

Homeowners shouldn't get too excited, though, as Baumohl predicted median prices will post year-over-year gains of no more than 6 percent by next year.

By the NAR measurement, prices nationwide were down 6.3 percent in May, falling faster in big cities. The Standard & Poor's/Case-Shiller home price index of 20 cities fell by 15.3 percent in April compared with a year before, dropping prices to their lowest levels since August 2004.

Meanwhile, shares of Fannie Mae, officially Federal National Mortgage Corp., and Freddie Mac, or Federal Home Loan Mortgage Corp., stabilized Tuesday, a day after plunging to early 1990s levels on worries they might need billions of dollars in new capital if a new accounting rule is put into effect.

Fannie Mae shares rose $1.88, or 11.9 percent, to $17.62 Tuesday, a day after plunging more than 16 percent. Freddie Mac shares rose $1.55, or 13 percent, to $13.46 after sliding nearly 18 percent on Monday.

Although the government is widely expected to stand behind Fannie and Freddie's debt should the companies be unable to meet their obligations, shareholders' interests are not protected.

"The shareholders are the ones who are at huge risk here ... they could potentially get wiped out," said Nigel Gault, chief U.S. economist at Global Insight.

Highlighting those risks, shares of mortgage lender IndyMac Bancorp Inc. plummeted to an all-time low of 34 cents Tuesday morning before recovering slightly. On Monday, the mortgage lender said it stopped accepting new loan submissions in its main mortgage lending divisions and plans to slash more than half its work force.

As the housing market and broader economy continue to sag, Senate lawmakers appeared on track to approve, possibly by the end of the week, a rescue plan designed to save hundreds of thousands of homeowners from foreclosure.

But it was uncertain whether lawmakers would reach a deal with the White House, which is balking at key portions of the bill, particularly $3.9 billion included for buying and fixing up foreclosed properties. Democrats argue the money is key to preventing neighborhood blight, but most Republicans call it a bailout for lenders who helped cause the mortgage mess.