U.S. stocks seen opening flat Tuesday

At 4:36 a.m. ET, Nasdaq and S&P were higher, with a comparison to fair value pointing to a flat opening for Wall Street.

Stocks have been trading in volatile fashion ahead of the Fed's meeting on Sept. 18. Investors are expecting the central bank to lower rates by at least a quarter of a percentage point, but are also hoping for as much as a half percentage point cut.

Attention will be focused on a speech Bernanke is due to give Tuesday in Berlin. As usual, investors will be on the lookout for any hints about what the Fed intends to do with interest rates next week. Last month, Bernanke the central bank is prepared to cut rates to protect the broader economy from the impact of the global credit crunch.

A disappointing employment report issued last week raised worries that the problems in the housing and financial markets are spreading to the rest of the economy.

On the economic front, the July trade balance report is due at 8:30 a.m. ET. The trade gap is expected to have widened to $59.0 billion from $58.1 billion in the previous month, according to a consensus of economists surveyed by Briefing.com.

Shares in Asia closed mostly higher Tuesday, while major indexes in Europe were higher in early trading.