New York (CNN Business) US stocks again sold off sharply on Thursday as worries about coronavirus mounted. The S&P 500 posted its worst day since August 18, 2011, and the three main indexes fell into correction territory. Stocks are on track for their worst week since the financial crisis.

Thedropped 1,191 points, or 4.4% in its worst one-day point drop in history. The index has fallen more than 10% below its most-recent peak, putting it in correction.

Theclosed down 4.4% and finished the day below the 3,000 point mark. The index is also in correction territory.

All three indexes are on track for their worst week since the fall of 2008, the midst of the financial crisis.

FTSE 100 UKX In the United Kingdom, thealso fell into correction territory Thursday . This is the market's first correction since December 2018.

Stocks still aren't all that close to a bear market, which is defined as 20% or more below the most recent peak. The S&P 500 is 12% below its peak.

Global equities have been selling off around the world all week as investors fret about the spread of the virus. In the United States, stocks spent all of Thursday in the red, despite a short-lived rebound around midday during which the S&P and the Nasdaq briefly emerged from correction.

"The game has changed with Italy and also with the new case in California," said Keith Buchanan, portfolio manager at GLOBALT Investments, in reference to the latest coronavirus cases.

That said, investors would do well to remember that a "10% pullback after the kind of run US equities have been having is not the worst scenario," Buchanan said.

Still, safe haven investments like bonds are up on Thursday and the 10-year US Treasury yield fell to a new all-time below 1.28%. Bond yields and prices move in opposition to each other.

In the energy space, US oil prices fell yet again as investors worries about a drop in demand. US oil futures settled down 3.4% at $47.09 a barrel.

Worries about the coronavirus outbreak mounted this week, with the US Centers for Disease Control and Prevention saying it expects cases in the United States to rise. The virus has now infected more than 82,000 people worldwide, with the vast majority of cases in China.

Microsoft MSFT announced that late Wednesday. Goldman Sachs GS Corporations continue to warn that they won't meet their first quarter earnings targets.said in a report Thursday that it now thinks US companies will generate zero earnings in 2020.

"What's even more disconcerting is that the news headlines haven't been all that bad yet," said Paul Hickey of Bespoke Investment Group. "Right now, it's the fear of what could happen that's driving the markets rather than what is actually happening."