Wall Street reversed course on Thursday — twice — with the Dow Jones Industrial Average shedding 611 points, only to erase those losses in a dramatic final hour of trading that saw the blue-chip index soar into positive territory.

The tech sector had led a morning pullback, after a report that President Donald Trump may ban American companies from using telecommunications equipment built by Chinese tech giants Huawei and ZTE, a move that would threaten the fragile cease-fire between the world's two largest economies.

Dow stalwarts Exxon, Boeing, and Caterpillar also fell, with shares down by more than 1.5 percent each.

But the market rallied just minutes before the closing bell, with the Dow surging upwards to close 250 points higher, or 1.1 percent. The S&P 500 closed 0.85 percent higher, having fallen to 2.8 percent at its session low. The Nasdaq Composite index swung from a loss of 3.3 percent to close up by 0.4 percent.

Thursday's wild swing of almost 900 points on the Dow follows a historic surge of almost 1,100 points on Wednesday, when it rallied by 1,086 points to close at 22,878, the biggest upside move since March 2009.

The continuation of a partial government shutdown is still weighing heavily on markets, with investors nervous about turmoil in the White House and tension between Trump and the Federal Reserve, which announced last week that it plans to continue to raise rates at a steady pace through at least 2019.

Trump has repeatedly rebuked Fed Chairman Jerome Powell for hiking the central bank's benchmark lending rate, saying in October, "I have a hot economy going. Every time we do something great, he raises the interest rates." Reports that Trump intended to fire Powell contributed to record losses on Wall Street on Christmas Eve, ramping up anxiety among Washington-weary traders.

Although December is usually a quiet month for markets, this year has been the worst December for U.S. stocks since 1931. But Wall Street is hoping for one final surge: Since 1950, markets have rallied every year during the last five days of December.