Stocks are at their lowest level since July (SPY, SPX, DJI, IXIC)

Thomson Reuters

Stocks were lower in trading on Tuesday, and the S&P 500 declined to its lowest level since July.

October was the worst month for the market since January, and the S&P 500 trimmed its year-to-date gain to 3% from about 6%. An uneven start to the third-quarter earnings season rocked the share prices of some big companies on the major indexes that reported last month.

Next Tuesday's presidential election also looms, though many investors are not making big trading decisions ahead of the vote. The Mexican peso, which has been considered a proxy for election sentiment, fell after a new poll showed Donald Trump leading Hillary Clinton by a point.

At 2:23 p.m. ET, the Dow is down 187 points (1.03%), the S&P 500 is down 26 points (1.25%), and the Nasdaq 100 is down 70 points (1.37%).Thomson ReutersThe economic data released earlier on Tuesday was mixed. The ISM's manufacturing purchasing managers' index came in at 51.9 for October, beating expectations. But construction spending fell unexpectedly, dropping 0.4%.

The Federal Reserve is meeting in Washington on Tuesday and Wednesday. Wall Street is looking forward to a statement on Wednesday confirming that the Fed is likely to raise interest rates at its December meeting.

Fed fund futures reflected a 69% chance that the Fed would raise its benchmark rate next month and a 19% probability for a move this week.

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