Wall Street was on track to open lower on Monday, adding to last week`s losses on rising uncertainty over a U.S. tax reform deal.
Senate Republicans have unveiled a new tax plan that differs from the House of Representatives` version and there are few signs of a compromise.
Hopes of lower taxes, one of President Donald Trump`s main campaign promises, have helped drive the S&P 500 up 20 percent since the 2016 presidential election.
"We`re entering a period of uncertainty, until the tax bill is either passed or till we have more details," said Peter Cardillo, chief market economist at First Standard Financial in New York.
"Any disappointment on corporate tax deductions will probably set the stage for the market to pull back."
The S&P 500 and the Dow ended the week lower on Friday for the first time in nine weeks.
With third-quarter earnings season on its last leg, investors are closely tracking developments around the tax bill as well as economic data to make their bets.
With the Federal Reserve`s policy meeting a month away, Philadelphia Fed President Patrick Harker said that he expected to back an interest rate hike next month despite caution over low inflation.
Harker said he expected the Fed to raise rates three times next year as long as inflation remains on track.
At 8:29 a.m. ET (1229 GMT), Dow e-minis were down 81 points, or 0.35 percent, with 32,366 contracts changing hands.
S&P 500 e-minis were down 7 points, or 0.27 percent, with 206,155 contracts traded.
Nasdaq 100 e-minis were down 22.25 points, or 0.35 percent, on volume of 36,498 contracts.
General Electric was up 1.32 percent premarket after the industrial conglomerate said it would halve its quarterly dividend, which is expected to save about $4 billion in cash annually.
Toymaker Mattel jumped about 23 percent after a report that rival Hasbro has made an approach to acquire the company. Hasbro rose 3.3 percent.
JD.com rose nearly 4 percent as China`s second largest e-commerce firm reported revenue that beat estimates, as the firm attracted more shoppers.
(This article has not been edited by Zeebiz editorial team and is auto-generated from an agency feed.)