* Bernanke offers no clues on steps to boost growth
* New jobless claims rise; July trade gap narrows
* Stocks down: Dow 0.8., S&P 0.9 pct, Nasdaq 0.7
* For up-to-the-minute market news see [STXNEWS/US] (Updates to mid-afternoon)
By Edward Krudy
NEW YORK, Sept 8 (Reuters) - U.S. stocks fell further on Thursday after Federal Reserve Chairman Ben Bernanke said the central bank would spare no effort to boost the economy but gave no details of steps policymakers might take.
Indexes seesawed between modest gains and losses for most of the day but headed to session lows shortly after the comments, although trading was volatile and volume was light.
Banks were the biggest decliners after sharp gains on Wednesday. The KBW Bank Index <.BKX> was down nearly 2.5 percent.
"The Fed hasn't come out with more options or tools that the market wants or was expecting," said Tim Ghriskey, chief investment officer of Solaris Asset Management in Bedford Hills, New York. "The market was disappointed because this wasn't a game changer."
Bernanke's closely watched speech comes not quite two weeks ahead of the Fed's next scheduled policy meeting, on Sept. 20-21.
Trade was also cautious ahead of a speech by U.S. President Barack Obama calling for urgent steps to spur the economy and create jobs. Obama, who is to speak at 7 p.m. EDT (2300 GMT), is expected to lay out a $300 billion plan to include tax cuts for the middle class and businesses and new infrastructure spending. [ID:nN1E7870HE]
The Dow Jones industrial average <.DJI> dropped 94.07 points, or 0.82 percent, to 11,320.79. The Standard & Poor's 500 Index <.SPX> fell 10.83 points, or 0.90 percent, to 1,187.79. The Nasdaq Composite Index <.IXIC> lost 17.75 points, or 0.70 percent, to 2,531.19.
Among bank shares, JPMorgan
On the upside, Yahoo shares
Shares of SanDisk Corp
Earlier, data from the Labor Department showed weekly jobless claims rose to 414,000 from an upwardly revised 412,000 in the prior week.
Separately, the government said the U.S. trade deficit narrowed considerably in July, a positive signal for economic growth in the third quarter after a sluggish first half. [ID:nN1E7870A9] (Reporting by Edward Krudy; Editing by Leslie Adler)