Stocks south of the border rode the crest of higher oil prices and piled more gains on top of last week's record performances.
The Dow Jones Industrials leaped 246.88 points to greet noon at 28,177.21
The S&P 500 strengthened 24.23 points from Friday's all-time high, at 3,421.39.
The NASDAQ Composite added 62.98 points to Friday's all-time peak, at 11,374.78.
Shares of airlines and cruise operators gained amid the coronavirus treatment developments. United Airlines rose by more than 7% along with Delta and American. Carnival gained 7.2%. Norwegian Cruise Line picked up 8.2%, and Royal Caribbean advanced 3.7%.
Earlier in the session, shares of Big Tech companies such as Apple and Microsoft led the market gains. However, they rolled over in late-morning trading.
Monday's early gains come as the number of new coronavirus cases continues to decline in the U.S. Since spiking by more than 64,000 cases, the number of new daily infections in the U.S. has not topped 49,000, according to Johns Hopkins University. On Sunday, there were less than 37,000 new confirmed cases.
On Sunday, the U.S. Food and Drug Administration issued an emergency use authorization of convalescent plasma for hospitalized COVID-19 patients, a treatment that uses blood plasma donated by people who've recovered from the virus.
President Donald Trump said at a news conference Sunday that the plasma treatment cuts the mortality rate by 35%.
The Trump administration is also considering fast-tracking an experimental coronavirus vaccine developed in the U.K. for use in the United States ahead of the nation's upcoming presidential election, according to a Financial Times report.
Shares of airlines and cruise operators gained amid the coronavirus treatment developments. United Airlines rose by more than 1% along with Delta and Southwest. Carnival gained more than 2%. Norwegian Cruise Line and Royal Caribbean advanced 1.3% each.
A seemingly unstoppable rally in major technology shares last week pushed the S&P 500 to levels above its previous record set before the pandemic. The broad equity benchmark posted its fourth straight positive week and closed at a fresh record on Friday.
Apple jumped more than 8% last week ahead of its four-for-one stock split, bringing its 2020 gains to nearly 70%. Those gains continued on Monday.
Prices for the 10-Year Treasury sagged, raising yields to 0.65% from Friday's 0.63%. Treasury prices and yields move in opposite directions.
Oil prices strengthened 26 cents to $42.60 U.S. a barrel.
Gold prices slumped $8.20 to $1,938.80 U.S. an ounce.