Stocks headed for weak open

NEW YORK (CNNMoney.com) -- U.S. stocks were headed for weak open Friday, as Federal Reserve Chairman Ben Bernanke defended the central bank's plan to spur economic growth, in an early morning speech in Germany.

Dow Jones industrial average (INDU), S&P 500 (SPX) and Nasdaq (COMP) futures were all lower ahead of the opening bell. Futures measure current index values against perceived future performance.

With no economic data or major corporate reports on the agenda for Friday, investors are backing away from Thursday's rally, said Art Hogan, chief market strategist at Jefferies & Co.

Stocks rallied Thursday, with all three major indexes gaining 1.5%, as worries about Ireland's debt woes eased and GM's newly issued stock rallied on its first day of trading.

"I think the futures market right now is really just representing a day-after affect," Hogan said. "We have a bit of a hangover after a rally yesterday."

He said that if there hadn't been such a strong rally yesterday, Wall Street would likely a strong gains Friday, on the back of recent signs of stability: Irish officials becoming more amenable to receiving aid from the International Monetary Fund and the Central Bank of China raising its reserve requirement ratio.

Economy: The Central Bank of China raised the banks' reserve requirement ratio by 50 basis point, or half a percentage point. That's the fifth time this year that the central bank has raised the reserves that banks are required to keep in their vaults.

In his speech, Bernanke defended the Fed asset-buying plan, saying the strategy has worked in the past and could help reduce unemployment in the United States. He also argued that nations need to work together to correct global imbalances, as the world economy recovers at an uneven pace.

On Thursday, officials in Dublin signaled that Ireland is open to accepting aid from the IMF and European Central Bank to shore up its troubled banking sector.

World markets: European stocks were lower in morning trading. Britain's FTSE 100 lost 0.9%, the DAX in Germany fell 0.1% and France's CAC 40 slid 0.5%.

Asian markets ended the session mixed. The Shanghai Composite gained 0.8% and Japan's Nikkei rose 0.1%, while the Hang Seng in Hong Kong lost 0.1%.

Companies: Dell (DELL, Fortune 500) could be among the stocks to watch, after the personal computer maker reported late Thursday that booming sales to businesses sharply lifted its profit last quarter. Dell shares were up in premarket trading.

General Motors raised $20.1 billion in an initial public offering late Wednesday, with shares debuting on the NYSE Thursday. Shares of GM (GM) closed at $34.19 on Thursday, up nearly 4% from the $33-a-share offering price. The stock was flat in premaket trading.

Currencies and commodities: The dollar weakened against the euro, the Japanese yen and the British pound.

Oil for December delivery gained 3 cents to $81.88 a barrel.

Gold futures for December delivery rose $3 to $1,356 an ounce.

Bonds: The price on the benchmark 10-year U.S. Treasury increased, pushing the yield down to 2.89% from 2.90% late Thursday.