The Dow Jones Industrial Average soared more than 1,100 points, or 4.5%, on hopes for more stimulus measures from around the globe to fight the virus outbreak.
Health care companies led the gains after Joe Biden solidified his contender status for the Democratic presidential nomination. Investors see him as a more business-friendly alternative to Bernie Sanders.
Congressional leaders agreed on an $8.3 billion bill to battle the new coronravirus, and investors are anticipating that more central banks will follow the Federal Reserve's lead in cutting rates.
The S&P 500 jumped 4.2% and the Nasdaq rose 3.8%. The yield on the 10-year Treasury rose slightly.