Shortly after noon, the Dow Jones industrial average was down 28 points at 15,265, a drop of 0.2 percent.
The Standard & Poor's 500 index was down five points at 1,645, a slip of 0.3 percent.
The market is headed for its first weekly loss in five weeks. Anxiety over the Federal Reserve's bond-buying program was the main culprit. Some investors are concerned that the Fed will scale back its effort to support the economy sooner than they expected.
The S&P 500, widely used by mutual funds as a proxy for the stock market, is down 1.7 percent for the week. It's still up 15 percent so far this year.
Marty Leclerc, the managing partner of Barrack Yard Advisors, an investment firm in Bryn Mawr, Pennsylvania, said the weekly drop wasn't cause for concern. Even market rallies have to take the occasional break.
"It's up like a rocket blast this year," he said of the stock market. "For there to be a little bit of a pullback is perfectly understandable."
Sears plunged 17 percent after the department-store chain reported a steep quarterly loss and slumping sales after the market closed Thursday. Sears lost $9.72 to $48.64.
Procter & Gamble surged 4 percent. The household-products giant said late Thursday that it's bringing back its former CEO, A.G. Lafley, to run the company. The world's largest consumer-products maker, whose brands include Tide and Crest, is trying to increase sales in the face of tough competition. P&G rose $3 to $81.70.
The Nasdaq composite sank 11 points, or 0.3 percent, to 3,448. Nine of the 10 industry groups in the S&P 500 dropped.
Stocks fell Friday despite an encouraging report on U.S. manufacturing. The government said orders for long-lasting manufactured goods rebounded in April, helped by demand for aircraft and stronger business investment. The report suggests economic growth may hold steady this spring.
In the market for U.S. government bonds, the yield on the 10-year Treasury note slipped to 2.01 percent from 2.02 percent late Thursday.
The price of crude oil fell 66 cents to $93.59 a barrel. Gold slipped $4 to $1,387 an ounce.
Trading was light ahead of the long weekend. U.S. financial markets will be closed Monday for Memorial Day.
Among other stocks in the news Friday:
— Intuitive Surgical gained 5 percent after a jury decided in favor of the maker of robotic medical equipment in the first of many suits filed against the company. The plaintiffs argued that Intuitive was negligent in training doctors to use its equipment. Intuitive's stock rose $24.08 to $502.54.
— Titan Machinery plunged 9 percent. The company, which deals in agricultural and construction equipment, said late Thursday that weaker revenue will lead it to a wider quarterly loss than it had expected. Titan's stock lost $2.04 to $20.47.