U.S. stock index futures fell on Wednesday a day after the Dow posted its seventh consecutive advance in weak trading volume that could signal the rally is wilting.

The market's attention will turn to Washington as Federal Reserve Chairman Ben Bernanke testifies before a House committee on the economy. Last week Bernanke said the recovery still needs help from the Fed despite signs of improvement.

Investors want to see the balance he's going to have between policies to promote growth and employment and the recent fear of inflation in commodities, said Rick Meckler, president of investment firm LibertyView Capital Management in New York.

Bernanke is scheduled to appear before the House Budget Committee beginning at 10 a.m.

Earnings will also be in the spotlight. Dow components Coca Cola Co and Cisco Systems Inc are expected to post results later Wednesday.

It will be interesting to see how Coke is being affected by food inflation, Meckler said.

Cisco hasn't participated in a phenomenal tech rally, he said. If they can make clear they are back on track, the stock can jump forward.

Blue-chip Walt Disney Co reported after the bell on Tuesday a stronger-than-expected 54 percent surge in profit. Its shares jumped 4.7 percent to $43.10.

S&P 500 futures fell 3.7 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures dropped 23 points and Nasdaq 100 futures lost 6.5 points.

The S&P 500 faces strong resistance in the 1,324-1,333 area, with the upper limit coinciding with a 100 percent advance from the lows hit in March 2009. Short-term technical support for the benchmark kicks in at 1,313.

The London Stock Exchange is to buy the Toronto Stock Exchange operator TMX in an all-share deal to create a major center for trading in mining shares if likely political opposition in Canada can be overcome.

On Tuesday U.S. stocks hit fresh multiyear highs after strong sales by McDonald's boosted optimism on consumer spending.

(Reporting by Rodrigo Campos; Editing by Kenneth Barry)

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