Investors turned cautious Tuesday ahead of the end of the quarter and before the 1st presidential debate between President Trump and Joe Biden.

The Dow shed 131 points. The S&P 500 dipped 16 points. The Nasdaq lost 32 points.

Hugh Johnson of Hugh Johnson Advisors says the only way to sum up Tuesday's action:

"We've probably come too far too fast. We probably have a valuation problem, not just technology stocks, but also the general market. And everybody's sort of a little bit skittish now looking for perhaps the second leg to drop or us to have a further correction in the stock market. So general skittishness and, of course, the ongoing concerns about the election that's coming up."

Not even word of potential progress in Washington's debate over a new stimulus package was enough to move investors off the sideline. Speaker of the House Nancy Pelosi said she hopes there could be a deal this week with the White House after the Democrat's unveiled a new $2.2 trillion relief package. The proposed aid comes just days before airline layoffs are set to go into effect. There are hopes airlines could get a second bailout. It was still a down day for the group though. JetBlue was the biggest loser - falling more than 4 percent.

One other piece of promising news that went overlooked: U.S. consumer confidence surged by the most in 17 years. The September jump was a surprise given the ongoing health crisis and high unemployment.