U.S. stocks rose for a second straight session on Tuesday as investors bet Democratic candidate Hillary Clinton would win the U.S. presidential election.

Wall Street sees the former secretary of state as a status quo candidate lending stability to the markets, while Republican candidate Donald Trump's stances on foreign policy, trade and immigration are less certain.

Data company VoteCastr, which is providing real-time election information through news outlets, including Slate, showed Clinton with an early lead among voters in Florida, a must-win state for Trump.

Several investors said VoteCastr's data pushed stock prices higher, although many questioned its accuracy.

Clinton has a 90 percent chance of defeating Trump, according to the final Reuters/Ipsos States of the Nation poll released on Monday.

"The market's betting that a Clinton victory will lift the cloud of uncertainty we've been facing the last two weeks," said Michael James, managing director of equity trading at Wedbush Securities in Los Angeles. "We're basically back to where we were last week. The market had gotten oversold."

After starting the session at a slight loss, the Dow Jones industrial average ended up 0.4 percent at 18,332.43 points and the S&P 500 gained 0.38 percent to 2,139.53 points. The Nasdaq Composite added 0.53 percent to 5,193.49 points.

The CBOE Volatility index, dubbed Wall Street's "fear gauge," reversed an early increase and dipped 0.9 percent after having notched its biggest one-day drop since late June on Monday.

The iShares MSCI Mexico Capped ETF, known of late as the "Trump ETF," climbed 1.75 percent. The ETF is viewed as a barometer of Trump's chances of winning the election since his policies are considered negative for Mexico.

Clinton was on track to win 303 votes in the electoral college to Trump's 235, clearing the 270 needed for victory. She also leads Trump by about 44 percent to 39 percent in the popular vote, according to the Reuters/Ipsos poll.

The S&P 500 has surged 2.6 percent since the FBI said on Sunday it would not press criminal charges against Clinton over her use of a private email server, an announcement seen as improving her chances at the polls.

Shares of Smith & Wesson Holding rose 2.15 percent. Its sales have benefited in the past from fears among gun owners of increased gun control.

Aetna <AET.N> and Anthem jumped more than 2.7 percent. Both health insurers have gained from the Affordable Care Act, which Clinton has vowed to extend.

Advancing issues outnumbered declining ones on the NYSE by a 1.32-to-1 ratio; on Nasdaq, a 1.21-to-1 ratio favored advancers.

The S&P 500 posted 22 new 52-week highs and three new lows; the Nasdaq Composite recorded 60 new highs and 86 new lows.

About 7.0 billion shares changed hands on U.S. exchanges, above the 6.7 billion daily average over the last 20 sessions.