This is a live blog. Check back for updates.

4:01 pm: Dow drops more than 200 points

The Dow dropped about 227 points, posting its first losing week in three, as investors fled risk assets amid the intensifying fears around the deadly coronavirus. The S&P 500 dipped 1%, while the Nasdaq fell 1.7% to suffer its worst day since Jan. 27 as big tech led the broad market decline. Amazon, Apple and Alphabet all traded more than 2% lower, and Microsoft dropped 3.1%. The growing coronavirus worries reignited appetite for safe-haven assets, as investors pushed 30-year Treasury yield to an all-time low. — Li

3:19 pm: S&P 500 forward PE ratio hits highest level in nearly 18 years

Data compiled by FactSet showed S&P 500 traded at 19 times 12-month forward earnings as of Wednesday. That's the P/E's highest level since May 23, 2002, according to the data. That number is well above recent trends, eclipsing five, 10, 15 and 20-year averages. —Imbert

2:44 pm: Final hour of trading: Stocks head for first weekly decline in three

Heading into the final hour of trading, the major averages were all headed for their first weekly decline in three. The Dow traded more than 200 points lower, while the S&P 500 and Nasdaq both fell more than 1%. Traders also loaded up on U.S. bonds, pushing the 30-year rate to a record low. —Imbert

1:21 pm: Bonds are 'screaming' at the stock market right now

"As yields plummet, the bond market's screaming ever louder at the increasing disconnect between its outlook for the economy and that of the stock market, which has been signaling increased optimism for growth stocks," said Alec Young, managing director of global markets research at FTSE Russell. "It's more than just the coronavirus. The most recent downturn in bond yields started before mid-January, when coronavirus headlines first broke out. It's all about a gut check today." —Chang

1:13 pm: 10 S&P 500 stocks hit record highs, Exxon and Marathon Oil reach 52-week lows

12:57 pm: Declining NYSE stocks are double those rising

Around two stocks at the New York Stock Exchange are falling for every advancer as the broader stock market heads for its first weekly decline in three. About 1,800 NYSE-listed stocks were trading lower while around 950 advanced. —Imbert

11:46 am: Markets at midday: Stocks head for losing week on resurfacing coronavirus fears

The major stock averages were down around midday as resurfacing fears over the coronavirus and its economic impact dented sentiment. The Dow traded about 200 points lower, or 0.7%. The S&P 500 slid 0.8% while the Nasdaq was down 1.2%. —Imbert

11:39 am: Market sees rate cuts ahead despite Fed denials

Federal Reserve officials have been consistent in saying they don't see additional rate cuts this year, but the markets don't believe them. Traders on Friday, in fact, were pricing in a 60% chance of a reduction by June, up from about 50% just a day ago. They're also assigning a 63% probability to a second cut before the end of the year. That comes amid fears that the coronavirus could exact greater economic damage than Fed officials are estimating. No fewer than three central bank leaders appeared on CNBC over the past two days, each saying they think the virus's impact will be short-lived and Fed policy is in the right place considering broader economic conditions. —Cox

10:56 am: Zero-fee trading behind Tesla, Virgin Galactic 'parabolic moves'?

Wells Fargo equity strategists said that they "are fascinated by the parabolic moves" recently by Virgin Galactic and Tesla. The firm said in a note that "one theory we think has some merit is that the seeds for these moves were planted in October when online brokers cut commissions to zero. At the time few people predicted any real macro ripple from this change." Both stocks are among the most popular on the trading platforms of Fidelity, TD Ameritrade, SoFi and Robinhood, CNBC reported on Wednesday. —Sheetz

10:49 am: China doubles count of new virus cases for Wednesday in revision

Chinese officials have revised the number of new coronavirus cases in the Hubei province on Feb. 19 to 775 from 349, according to Reuters. The U.S. stock market fell further after the news, with the Dow Jones Industrial Average down more 300 points, or roughly 1.1%. — Pound

10:24 am: LatAm currencies get hit as coronavirus fears rise

The Brazilian real, Mexican and Chilean pesos all fell against the U.S. dollar as forex traders dumped riskier currencies in favor of safer ones such as the greenback. The dollar hit a record high against the Brazilian real, reaching 4.4064, before pulling back from that level. Meanwhile, the Mexican peso fell more than 1% against the U.S. currency, hitting its lowest level against the dollar since Dec. 13. The Chilean peso, meanwhile, fell to its weakest level since Nov. 29 against the dollar. —Imbert, Francolla

10:17 am: Service sector PMI hits lowest level since 2013

The IHS Markit services purchasing manager's index dipped into contraction territory for February. The flash PMI reading came in at 49.4, a 76-month low and down from 53.4 in January.The flash PMI for manufacturing also declined to 50.6 from a final reading of 51.9 in January, but stayed above the key 50.0 level that separates contraction and expansion. Both readings were well below expectations, according to Dow Jones. —Pound

10:11 am: January home sales beat estimates

Existing home sales declined in January 1.3% in January, but the annualized rate of 5.46 million homes still came in above expectations. Economists polled by Dow Jones projected a gain of 5.34 million. The better-than-expected sales data follows strong reports for housing starts and building permits earlier in the week. The housing sector is one reason that BNY Mellon Investment Management expects an uptick in U.S. growth by the middle of the year, said Alicia Levine, the group's chief strategist. "If you look at the housing data over the last week or so, the housing data has been really good, much stronger than expected," Levine said before Friday's sales data was released. "And that tends to pull things up like construction and manufacturing and all the industries that are associated with it." —Pound

9:59 am: Dropbox surges 16% after earnings beat

Shares of Dropbox jumped more than 16% after the cloud file-storage company posted better-than-expected quarterly numbers. Dropbox posted a profit of 16 cents a share on revenue of $446 million. Analysts expected earnings of 14 cents per share on sales of $443 million, according to Refinitiv. The company also announced a $600 million buyback. —Imbert

9:56 am: 30-year Treasury bond yield hits all-time low

The yield on the benchmark 30-year Treasury bond fell to an all-time low under 1.9% as of about 9:40 a.m. ET. The historic lows for the 30-year came as investors grew more nervous about the economic fallout from the coronavirus. The Friday bid for U.S. debt came as the Dow Jones Industrial Average fell more than 250 points in a market-wide pivot away from riskier assets. — Franck

9:41 am: Deere earnings pop 8% on strong earnings

Deere shares jumped about 8% after the construction equipment maker reported earnings per share and revenue that easily beat analyst expectations. The company posted a profit of $1.63 per share on revenue of $6.53 billion. Analysts polled by Refinitiv expected earnings of $1.25 per share on sales of $6.409 billion. CEO John May said fiscal first-quarter results showed "early signs of stabilization" in the U.S. farm sector. —Imbert

9:31 am: Dow falls more than 100 points at the open

Amid the lingering fears about the coronavirus, the Dow fell about 120 points to start Friday's session, on pace to post its first weekly loss in three weeks. The S&P 500 dipped 0.5%, while the Nasdaq Composite dropped 0.4%. The so-called FANG stocks are all in the red at the open. — Li

9:23 am: Citi Private Bank CIO: 'Rush to safety' could end badly for investors when coronavirus outbreak abates

David Bailin, chief investment officer at Citi Private Bank, told CNBC on Friday that investors could get burned in a "rush to safety" due to coronavirus concerns. Gold, treasuries, utilities stocks and growth stocks "actually are going to turn out to be dangerous places in the market to be ... when we get over the hump of the coronavirus," Bailin said in a "Squawk Box" interview. "We think those are going to turn out to be places where the market is overvalued, and we'll actually see reversals." Bailin said he's "constructive" on the overall market. However, he advises investors to pick their spots because, in his view, the S&P 500 is "fully priced." —Belvedere

8:33 am: Hedge funds are crowding into a few stocks

Goldman Sachs notes that "the typical hedge fund now carries 69% of its long portfolio in its top 10 positions, up from 55% in 2005." Top favorites of the hedge fund crowd include Amazon and Microsoft, according to a Goldman note. The firm also points out that all investors are crowding into the biggest stocks and that could be worrisome. "In the S&P 500, the 10 largest companies account for 25% of market cap, nearing the 27% share reached at the peak of the Tech Bubble in 2000," the Goldman note stated. —Melloy

8:19 am: JPMorgan technical analyst calls for a market setback, says 'short-term systematic sell signals' triggered

The U.S. stock market could be subjected to near-term headwinds as a slew of "systematic sell signals" are tripped up, JPMorgan technical analyst Jason Hunter said in a note to clients. Hunter noted that as the S&P 500 hit record highs, it did so with "much less momentum and weaker internals." Hunter also pointed to how narrow the leadership in the market has been, noting: "With only a select group of stocks powering the rally … multiple momentum and internal divergences provide technical signals that increase the probability for a short-term setback." —Imbert

8:17 am: Here are Friday's biggest analyst calls of the day

7:58 am: Stocks set to fall as coronavirus cases spike