NEW YORK (AP) — Good news about the U.S. economy wasn't enough to sustain an early rise in the stock market Tuesday.

Stocks were edging lower by early afternoon. Encouraging news about the housing market and trade had nudged indexes higher in the early going.

Jim Paulsen, chief investment strategist at Wells Capital Management in Minneapolis, said it's likely that traders are looking ahead to Friday, when the Labor Department releases its closely watched jobs survey. That report, he said, could help determine what the Federal Reserve will do next.

"You gotta believe that people are getting ready for the end of the week," Paulsen said.

A strong report on Friday would normally send the stock market up. This time around, investors are also trying to guess when the Federal Reserve may start pulling back its support for the economy.

The market has turned volatile in the last two weeks as traders parse statements from Federal Reserve officials in an effort to anticipate when the central bank will reduce its $85 billion in monthly bond purchases. That has helped keep bond prices high and the yield, or interest, they pay low. The Fed's goal is to stimulate the economy by encouraging borrowing and investing with low interest rates.

Many investors expect long-term interest rates to rise when the Fed eases back on its bond purchases, which would have many repercussions for markets. More investors would likely be tempted to buy bonds instead of stocks once bond yields rise.

The current yield of 2.13 percent on the benchmark 10-year Treasury note is extremely low by historical standards. It's also nearly identical to the average dividend payment of 2.14 percent for stocks in the S&P 500.

The Dow Jones industrial average was down 33 points at 15,221 as of 12:20 p.m. It was up as much as 51 points in the first hour of trading, then turned lower shortly before 11 a.m.

The Standard & Poor's 500 index was down four points to 1,636, a decrease of 0.3 percent. Energy companies fell the most of the 10 industry groups in the index, 0.7 percent.

The Nasdaq composite was off three points at 3,461, a decrease of 0.1 percent.

Real estate data provider CoreLogic reported that home prices jumped 12 percent in April from a year earlier, the biggest gain since February 2006.

The government reported that the country's trade deficit in April was narrower than economists had expected.

General Motors gained 2 percent on news that the company will be added to the S&P 500 index on Thursday, replacing H.J. Heinz Co. The ketchup maker's acquisition is getting bought by Warren Buffett's Berkshire Hathaway and the private equity firm 3G Capital. GM was up 75 cents to an even $35.17.

Dollar General slumped 8 percent, the biggest drop in the S&P 500. The discount-store chain cut its earnings and revenue forecast for the year ahead because it expects sales to slow. Dollar General's stock dropped $4.06 to $49.48.

SAIC dropped 1 percent, or 13 cents, to $14.75. The security and communications technology company posted a 31 percent drop in quarterly earnings late Monday, as government spending cuts crimped SAIC's revenue.

Salesforce.com announced plans buy the marketing software company ExactTarget for $2.3 billion. Salesforce fell 3 percent, or $1.13, to $39.91. ExactTarget jumped 52 percent, or $11.61, to $33.71.

The price of crude oil rose 72 cents to $94.17 a barrel and gold fell $14 to $1,397 an ounce.