U.S. President Donald Trump declares the coronavirus pandemic a national emergency as Vice President Mike Pence and Health and Human Services Secretary Alex Azar listen during a news conference in the Rose Garden of the White House in Washington, March 13, 2020. Jonathan Ernst | Reuters

President Donald Trump praised the Friday rebound in stocks, which came amid an ongoing bear market stemming from the coronavirus crisis and a day after the worst decline since the 1987 Black Monday market crash. "Biggest stock market rise in history yesterday!" Trump tweeted Saturday morning. Tweet The S&P 500, the U.S. stock market benchmark, jumped 9.2% on Friday, its biggest climb since October 2008 in the wake of the financial crisis. The Dow Jones Industrial Average jumped 9.4%, also for its biggest gain since October 2008. Its 1,985-point rise was its biggest point gain ever. The bounce in stocks follows a 10% plunge in the Dow of 2,352.60 points. Thursday's drop was its worst percentage decline since the 1987 crash and its biggest point decline ever. On Thursday, the S&P 500 plunged 9.5% and entered an official bear market, down more than 20% from its high.

Friday's rebound accelerated during Trump's press conference from the White House Rose Garden, where he declared the coronavirus pandemic a national emergency and announced greater availability of testing coming next week. Trump also took other steps the market appeared to like, including announcing the purchase of oil for the strategic petroleum reserve. That move sparked a late Friday turnaround in oil prices. Collapsing commodity prices have hit energy stocks hard and added to the stock market pain. Despite Friday's bounce, most investors were not ready to declare the bottom is in for the stock market amid this unfolding pandemic, which JPMorgan believes will cause U.S. GDP growth to be negative for the next two quarters.