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.
On Wednesday, financial shares sparked a broad rally, sending stocks to multi-year highs and marking the second straight winning day for the Dow.
Credit rating agencies Standard & Poor's and Moodys issued a warning on U.S. credit, citing mounting debt, according to The Wall Street Journal. Meanwhile, Spain held a successful auction of government debt.
Eurozone jitters have led to choppy trading this week, but markets are still trending higher.
"Stocks are slightly overbought right now so we might have a nominal pullback in the short-term," said said Chip Brian, chief executive of MySmartrend.com, which analyzes over 6,000 stocks in real time.
"But the uptrend will continue once the European debt crisis du jour simmers out and people realize that, while there's been issues with Spain, Greece, Portugal and Italy, no one's toppled," he added.
Economy: After a light start to the week, investors face a full day of economic reports Thursday.
The Department of Labor released its weekly jobless claims report before the opening bell. The government said that the number of Americans filing new claims for unemployment climbed to 445,000 last week.
This was much higher than forecast of 415,000 claims.
The government also said that continuing claims -- a measure of Americans who have been receiving benefits for a week or more -- fell to 3.8 million. This was lower than the forecast of 4.08 million.
The Producer Price Index, a measure of wholesale inflation, rose 1.1% in December, according to the Commerce Department. This was higher than the expected increase of 0.8%.
The Commerce Department said the trade balance was practically unchanged at $38.3 billion. This was better than expected. The trade balance was expected to have widened to $41.0 billion in November.
In the afternoon, Federal Reserve Chairman Ben Bernanke will speak at the Federal Deposit Insurance Corporation's forum on small business lending.
World markets: European stocks were mixed in morning trading, despite a Spanish auction of government bonds that was met with solid demand. The nation rose the $3.9 billion (3 billion euros) as hoped. But the results had little impact on markets because the results were widely expected, said Brian.
"The bond auctions in Spain went pretty well, but there still seems to be concern about other countries," he said. "I think it's a good thing that each of the countries in the eurozone are trying to seek their own footing instead of waving their hands in the air and saying 'save us'!"
Britain's FTSE 100 lost 0.3% and the DAX in Germany slipped 0.1%, while France's CAC 40 rose 0.5%.
Asian markets ended the session higher. The Shanghai Composite ticked up 0.2%, the Hang Seng in Hong Kong rose 0.5% and Japan's Nikkei gained 0.7%.
Companies: Share of Marathon Oil (MRO, Fortune 500) surged 11% in pre-market trading on news reports that it will split into two separate companies.
Shares of Williams Sonoma (WSM) gained 1% in pre-market trading after the company boosted its fourth-quarter earnings and sales guidance following strong holiday sales.
After the closing bell, Intel (INTC, Fortune 500) is expected to report a quarterly profit of 53 cents per share -- versus 40 cents a year ago.