Wall Street’s concern and confusion surrounding the coronavirus was in full view Friday, as the Dow’s 1,200-point opening volley deflated, erasing most gains, by lunchtime. Then the blue chip index got its second wind after President Trump declared a state of emergency over the pandemic.

The Dow Jones industrial average shot up nearly 2,000 points, about 10 percent. The Standard & Poor’s 500 and Nasdaq also surged more than 9 percent. It was Wall Street’s biggest rally since 2008.

Friday’s moves were in line with the hyperactive trading on display all week. S&P 500 futures spiked 5 percent, triggering the New York Stock Exchange’s “limit up” brake that’s designed to temper excessive optimism and ensure orderly trading at the open. On Thursday, Wall Street’s had its worst trading day since the 1987 crash. The brutal sell-off came even as central banks around the world moved to shore up the economy against coronavirus fallout, which has battered global markets for weeks and disrupted many facets of daily life.

“The day-to-day volatility is a sign that investors don’t know what to do,” David Donabedian, chief investment officer of CIBC Private Wealth Management, wrote in commentary Friday.“ People are casting about so the period of extraordinary volatility is probably not over. Until we see more calm in the market, and better news on the path of COVID-19, a sustained recovery in markets is unlikely.”

Emergency action by the Federal Reserve to free up $1.5 trillion to smooth operations of the massive U.S. Treasury market and an Oval Office speech from President Trump outlining the beginning of the White House’s response to the U.S. outbreak sent investors into complete panic Wednesday, resulting in a jaw-dropping 10 percent decline for the Dow and the week’s second forced halt to trading.

Wall Street’s stunning meltdown over the past month has erased most of the stock market gains since Trump’s surprise election in November 2016. At its Feb. 12 peak, the Dow had climbed more than 61 percent; by Thursday’s close, that number had been shaved to roughly 11 percent.

“The coronavirus likely tips us into a recession because we were hit with a one-two punch from the virus,” said Dan Niles of AlphaOne Capital Partners, a San Francisco hedge fund. “It is both demand and supply destruction, unlike 9/11 or the tech bubble bursting, which was just demand.”

Asian markets were gutted by losses Friday, with Japan’s Nikkei 225 shedding more than 6 percent, while Hong Kong’s Hang Seng Index closed down about 1.1 percent. But European markets shared in the rebound after one of their worst days in history, boosted by intervention plans from the European Central Bank. The benchmark Stoxx 600 index was up 4.4 percent in midday trading. Earlier this week, the World Health Organization designated the coronavirus a global pandemic. The disease has sickened more than 135,000 worldwide and killed nearly 5,000. And after months of edging closer, the coronavirus has taken root throughout the United States and upended daily life for the foreseeable future.