Futures for the Dow Jones industrial average, the S&P 500 and the Nasdaq 100 fall 0.5-0.6 percent, pointing to a weaker start for Wall Street on Tuesday.

Investors continued to worry there is not sufficient evidence of economic recovery to justify a 52 percent surge in the S&P stock market from the March low.

The FTSEurofirst 300 <.FTEU3> index of top European shares was down 1.1 percent at 961.64 points, reversing earlier gains.

The Institute of Supply Management's manufacturing index, due at 1400 GMT (10 a.m. EDT), is expected to have moved into positive territory in August for the first time since the recession began.

Forecasts of the 78 economists polled by Reuters gave a reading of 50.5, up from 48.9 in July. A reading below 50 points to contraction while a reading above 50 points to expansion.

Pending home sales probably rose 2.0 percent in July, down from June's 3.6 percent.

Michelle Meyer, an economist at Barclays Capital in New York, said she expected pending home sales to show a fall of 1 percent after a 16.5 percent surge over the prior five months.

Our forecast reflects the historical volatility of the data - there have never been more than five months of consecutive gains, she said. Construction spending is expected to be flat after a rise of 0.3 percent rise in June.

There are no major U.S. companies due to report earnings.

U.S. shares closed lower on Monday, as concerns about the global economy's health weighed on Wall Street following a sell-off in Chinese equities.

Bank of America is offering to repay part of the U.S. government bailout money, starting with the $20 billion it received in January to help with the acquisition of Merrill Lynch & Co, the Wall Street Journal reported on its website late on Monday.

Internet auction and services company EBay Inc has reached a deal to sell its online telephony unit Skype to a group of private investors, the New York Times said, citing two people briefed on its plans.

(Reporting by Brian Gorman; Editing by Dan Lalor)

Citigroup Investment