The Dow Jones industrial average rose about 10 points to 13,343 at 10:30 a.m. EDT. The Standard & Poor's 500 fell a fraction of a point to 1,436. The Nasdaq composite was up one at 3,115.
The Fed wraps up a two-day policy meeting around noon. Many investors think it will announce a third round of bond-buying to lower long-term interest rates, get people to borrow and spend more and push investors into stocks.
But the Fed may decide to take smaller steps to stimulate the economy, disappointing investors. It could decide to just extend its pledge to hold short-term interest rates near zero.
Investors are also worried about turmoil in the Middle East. Protesters stormed the U.S. Embassy compound in Yemen's capital Thursday, and there was violence around the U.S. mission in Cairo. The U.S. ambassador to Libya was killed Tuesday.
The Labor Department reported Thursday that the number of people seeking unemployment benefits jumped last week to the highest level in two months, though the figures were skewed in part by Hurricane Isaac.
The figures come after a disappointing jobs report last week. Employers added only 96,000 jobs in August, far below the average 226,000 a month added in the January-March quarter.
The government also said Thursday that wholesale prices rose 1.7 percent in August, the most in three years. They were driven up by higher costs for gas and food. Removing the impact of energy and food, however, the increase in prices has been mild.
The Dow rose to a four-year high Wednesday after Germany's highest court rejected calls to block the creation of Europe's rescue fund for indebted governments.
The attacks in the Middle East have pushed crude prices higher. Oil was up $1.12, or 1.1 percent, at $98.13 on the New York Mercantile Exchange.