STOCKS TUMBLE: Here's what you need to know

Stocks tumbled on Tuesday, with the S&P 500 touching its lowest level since July.

October was the worst month for the market since January, and the S&P 500 shaved its year-to-date gain to 3% from about 6%. The beginning of the third-quarter earnings season punctured the share prices of several companies on the major indices.

And in case you might not have been paying attention, we are now just a week away from the US presidential election. Although, as Business Insider's Akin Oyedele noted, many investors are not making big trading decisions ahead of the vote.

But first, the scoreboard:

• Dow: 18,038.71, -103.71,(-0.57%)
• S&P 500: 2,110.97, -13.89, (-0.72%)
• Nasdaq: 5,152.48, -36.39, (-0.70%)
• WTI crude oil: $46.83, -$0.03, (-0.06%)

1. The Mexican peso tumbled after the latest Washington Post/ABC News poll released showed Republican nominee Donald Trump leading Democratic nominee Hillary Clinton by 1 point. The currency was down by 1.9% at 19.2161 per dollar around 3:30 p.m. ET.
2. Investors reportedly pulled money from Jeff Gundlach's main fund for the first time since January 2014. According to Jennifer Ablan at Reuters, Gundlach's main fund - the DoubleLine Total Return Bond Fund - had a net outflow of $33.2 million in the month of October. According to Ablan, this is the first net outflow for the fund since January 2014.
3. The 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%.
4. Auto sales trounced expectations. According to Autodata, sales rose at a seasonally adjusted annual rate of 18.29 million. Analysts had estimated that total vehicle sales rose at a rate of 17.6 million, according to Bloomberg, little changed from last month.
5. Wall Street is standing by for confirmation from the Fed. The Federal Open Market Committee will conclude its two-day policy meeting in Washington on Wednesday. And in its statement afterward, market participants want to be convinced that the committee will raise its benchmark interest rate in December.
6. Tronc crashed by nearly 19% after Gannett terminated buyout talks. Gannett Media, owner of newspapers such as USA Today, has ended its pursuit of Tronc, the publisher of newspapers such as the LA Times and Chicago Tribune according to a statement from Gannett.
7. US gasoline futures spiked over 11% after Colonial Pipeline Co shut down its main gasoline and distillates pipelines after an explosion and fire in Shelby, Alabama, killed a worker. The incident was the second time in two months the company had to close the crucial supply line to the US East Coast.
8. US Treasurys got slammed ahead of the Fed's latest policy decision. Tuesday's selling has yields up nearly 5 basis points at the long end of the curve, and at their highest levels since the end of May.

Additionally:

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The US dollar tumbled.