It was one of the wildest weeks on Wall Street ever and the worst stock performance since the financial crisis. Here's what happened:

4:40 pm: Former White House economic advisor Gary Cohn says US needs to help workers

Gary Cohn, the former White House economic advisor and Goldman Sachs executive, told CNBC that the U.S. needs to quickly come to the aid of its labor force: "We need to bailout American workers right now." Cohn said the U.S. is "in recession," adding that "we've got a big issue on our hands." - Sheetz

4:34 pm: S&P 500 bear market deepens

4:20 pm: Dow at lowest point since December 2016

The Dow's close at 19,173 points marked its lowest level since December 2, 2016. In just this past week the Dow lost more than 4,000 points, making this its worst weekly point loss ever. On a percentage basis, March is set to be the worst month since September 1931 as the Dow has dropped more than 24%. Finally, all 11 sectors in the S&P 500 are now more than 20% below their respective 52-week highs, a drop that analysts define as a bear market. - Sheetz, Francolla

4:00 pm: Wall Street's worst week since 2008

The Dow Jones Industrial Average finished trading on Friday down 913 points, a drop of 4.55%, as U.S. markets concluded the worst week since 2008. Despite rallying earlier in the day, all three major indexes closed negative, with the S&P 500 and Nasdaq Composite down 4.3% and 3.8%, respectively. - Sheetz

3:55 pm: Valuation is 'completely out the window,' Charles Schwab strategist says

Charles Schwab chief investment strategist Liz Ann Sonders said on "Closing Bell" that the market won't bottom until the growth of coronavirus cases starts to flatten out and said that traditional valuation metrics do not make sense in this environment. "I think valuation is completely out of the window because we have the numerator and denominator completely imploding. What's unique about this particular crisis is that instead of just guiding down .... most of them that are most hit by this are simply withdrawing guidance," Sonders said. Sanders said she is telling clients to consider re-balancing their portfolios more frequently if possible. — Pound

3:54 pm: Crude suffers its worst week since 1991

The U.S. West Texas Intermediate crude dropped 11% Friday to $22.43 per barrel, posting its worst week since January 1991. It was also oil's fourth straight down week. So far this month, WTI is down nearly 44%, on pace for its worst month ever since the inception of the contract in 1983. -- Francolla, Li

3:20 pm: "Quad witching" may add more market volatility at close

Friday coincides with a quarter-end event, known as "quad witching" because it happens four times a year, when options and futures on indexes and individual stocks expire. This will add another source of volatility to the market, which has been swinging wildly in the ongoing coronavirus pandemic. Quadruple witching usually sees a surge in trading volumes. — Li, Sheetz

3:10 pm: Clearing firm Ronin Capital unable to meet capital requirements at CME, sources say

In yet another a sign that the turmoil in financial markets is putting extreme stress on some firms, one of the CME Group's direct clearing firms, Chicago-based Ronin Capital, was unable to meet its capital requirements on Friday, sources told CNBC's Scott Wapner. The move forced the exchange to step in and invoke its emergency protocols to auction off the portfolios. The CME Group's Chairman and CEO told CNBC Ronin isn't allowed to have outside clients so there were no customers harmed in the process. – Wapner, Melloy

3:07 pm: Oil drops 10%, giving back some of Thursday's surge

Oil fell on Friday, one day after U.S. West Texas Intermediate crude rallied more than 23% for its single best day on record. WTI shed 10.7%, or $2.69, to settle at $22.53 Friday. International benchmark Brent crude fell 5.23%, or $1.49, to settle at $26.98 per barrel. Oil is getting hit on the demand side from the coronavirus-induced travel slowdown, just as a price war has broken out between Saudi Arabia and Russia. The current OPEC+ production cuts expire at the end of the month, meaning nations will soon be allowed to pump as much as they please. Saudi Arabia has said that it plans to increase its production to a record 12.3 million barrels per day. As tensions between the two countries escalate, President Donald Trump said Thursday that the U.S. would get involved "at the appropriate time." WTI has shed 48% this month, putting it on track for its worst month in history. – Stevens

3:00 pm: Final hour of trading: Stocks tumble, Dow heads for worst week since 2008

With roughly one hour left in the trading session, Dow was on pace for its worst weekly performance since financial crisis of 2008. The 30-stock average traded 700 points lower, or over 3%. The Dow was also down more than 15% this week. The S&P 500 and Nasdaq have also lost 3.2% and 2.3%, respectively. — Imbert

2:38 pm: Hit to globalization will hurt recovery, Edward Jones strategist says

Edward Jones investment strategist Nela Richardson said on "Power Lunch" that the global impact of the coronavirus pandemic will prevent a sharp snapback for U.S. economy. "We are an economy fueled by globalization, and for all intents and purposes there has been a sudden stop in that flow of trade and people across borders. So that's going to amplify the time to recovery," Richardson said. — Pound

1:53 pm: Fed says it will increase mortgage bond buys

The Federal Reserve is adding to its planned mortgage purchases amid a rise in rates for home loans. As part of a broad scope of bond purchases, the central bank said Friday afternoon that it was adding $15 billion to the $32 billion in mortgage-backed securities (MBS) it had already planned. In addition, the Fed said it is committed to buying $100 billion in MBS next week. – Cox

1:20 pm: Fed extends $1 trillion daily repo operations to the rest of March

The Federal Reserve Bank of New York announced it will further extend its daily repurchase agreement operations (also known as "repo") to $1 trillion for the rest of March. Previously the Fed had said it would conduct the increased repos through this week. Repos are when banks submit high-quality collateral, such as Treasurys, in exchange for reserves from the Fed. Banks then use the money to fund their short-term operations. - Sheetz

12:31 pm: Goldman sees unprecedented stop in economic activity, with 2nd quarter GDP contracting 24%

Economists have been ratcheting down their economic forecasts, but none more than those at Goldman Sachs, who now see second quarter GDP contracting by 24%. The Goldman economists expect the economy to trough in the second quarter, after a first quarter contraction of 6%. By the third quarter, they see a rebound of 12% and fourth quarter growth of 10%. But they also see GDP declining 3.8% for the year and unemployment reaching 9%. Just five days ago, the economists had expected a 5% decline in the second quarter and a flat first quarter, but they said the sudden shutdown of large parts of the economy due to the virus is hitting the economy hard in the first and second quarter. Bank of America expects a 12% decline in the second quarter. - Domm

12:19 pm: Stock losses accelerate

Stock losses accelerated around midday as the White House held a press briefing on the coronavirus. The Dow fell 141 points for a loss of 0.7%, while the S&P and Nasdaq were down 1.4% and 0.4%, respectively. - Stevens

11:26 am: Cuomo toughens NY restrictions

Governor Cuomo said that 100% of the state's workforce must stay at home, except for essential personnel. Stocks were trending lower before the Cuomo announcement and fell into the red as the headline hit. Investors may be worrying about just how economically disruptive the coronavirus may be. - Melloy

11:14 am: The Fed adds municipal bonds to its asset purchases

The Federal Reserve said Friday it would extend its asset purchase program into short-term municipal bonds. Thus far, the central bank has limited its efforts to Treasurys and mortgage-backed securities in an effort to keep liquidty flowing through the system and to stabilize credit markets. The announcement sent the iShares National Muni Bond ETF surging, last up 1.5%. – Cox, Li

11:05 am: Stocks hardest hit by coronavirus bounce back

Entertainment and travel stocks like MGM Resorts, United Airlines, Carnival Corporation and Hilton rose 10% or more in trading. Shares of these companies have been battered in recent weeks, as the global coronavirus pandemic has sharply decreased travel and discretionary spending. - Sheetz

10:55 am: Bitcoin on pace for best week since June

Bitcoin on Coinbase surged more than 18% this week, on pace for its best week since June 28th when the crypocurrency gained 24.38%. Meanwhile, bitcoin futures (MAR) are up 25% this week, on track for their best week ever since the inception of the contract in December 2017. - Francolla, Li

10:35 am: Wall Street's fear gauge falls below 60



The Cboe Volatility Index, Wall Street's preferred fear gauge, fell to its lowest level in a week, breaking below 60. It was last down 12.4 points, or 17%, at 59.62. Earlier this week, the VIX surged above 80 and breached its 2008 financial crisis high. — Imbert

10:30 am: "Quadruple witching" makes Friday's market a wild card



Friday coincided with a quarter-end event called "quadruple witching," when options and futures on indexes and indiv idual stocks expire. This adds another source of volatility to the market's roller-coaster ride amid the coronavirus uncertainty. "Given the recent outsized level of volatility we've seen on almost every day, this expiration could easily be a wild one," said Matt Maley, chief market strategist at Miller Tabak. The Dow and the S&P 500 have been swinging between losses and gains during Friday's morning trading. Quadruple witching usually sees a surge in trading volumes. Just about an hour into Friday's session, the SPDR S&P 500 ETF Trust (SPY) has already traded more than 50 million shares, according to FactSet. — Li

10:15 am: Treasury Secretary Mnuchin postpones tax filing deadline to July 15



Treasury Secretary Steven Mnuchin said Friday that the IRS will postpone Tax Day to July 15 from April 15 in an effort to blunt the impact of the coronavirus. Mnuchin added that, at President Donald Trump's direction, all taxpayers and business will have this additional time to "file and make payments without interest or penalties." — Franck tweet

10:06 am: Analysts upgrade flurry of stocks as Wall Street pauses steep selling

Analysts upgraded a slew of stocks in Friday's calls of the day as investors hope for signs of a market turnaround. Wells Fargo upgraded Uber to overweight from equal weight.

JPMorgan upgraded Oracle to overweight from neutral.

Bank of America upgraded Nike to buy from neutral.

Piper Sandler upgraded Gilead to overweight from neutral.

JPMorgan upgraded Tyson Foods to overweight from neutral.

Citi upgraded Lululemon, Ulta, and Ross to buy from neutral.

KeyBanc upgraded Dollar Tree to overweight from sector weight.

Deutsche Bank upgraded UnitedHealthcare to buy from hold.

Bank of America upgraded Cardinal Health to buy from underperform.

Wells Fargo upgraded Snap to overweight from equal weight.

Guggenheim upgraded Pepsi, Monster, Constellation Brands, and Molson Coors to buy from neutral.

Mizuho upgraded Lam Research to buy from neutral.

Bank of America upgraded Colgate-Palmolive to buy from neutral. — Bloom

9:45 am: Dow, S&P 500 reverse gains to trade slightly lower, Nasdaq up 0.5%

The Dow and S&P 500 traded slightly lower 10 minutes after the opening bell, but the Nasdaq Composite rose 0.5% as Microsoft, Amazon, Apple, and Facebook all gained. Some stocks that had taken outsized beatings amid coronavirus headlines bounced on Friday with MGM Resorts up 18%, Wynn Resorts up 9.7%, Carnival up 7.3% and Hilton Worldwide up 5.8%. UnitedHealth led the Dow higher while Goldman Sachs had the largest negative impact on the 30-stock index. — Franck

9:31 am: Stocks open in the green, Dow up 100 points

U.S. stocks attempted a two-day rally on Friday, with all three major averages opening in positive territory. The Dow Jones Industrial Average rose about 140 points at the open. The S&P 500 rose 0.85% and the Nasdaq jumped 1.5%. — Fitzgerald

9:08 am: Sports retailers Lululemon & Nike gain after upgrades

Shares of Lululemon and Nike rose 5% and 1% respectively during premarket trading on Friday after bullish calls from Street analysts. Citi upgraded Lululemon to a buy, saying the company should fare better than most retailers amid the coronavirus outbreak given the brand's strong e-commerce business. "Looking beyond near-term disruptions, LULU is a standout in retail and we do not believe their long-term earnings power is at risk. They have a solid balance sheet and their business is likely to rebound strongly on the other side," Citi said. Shares of Lululemon have shed 41% in the last month. When it comes to Nike, Bank of America said the company is poised to continue growing market share. The firm upgraded Nike to a buy rating, citing strength in both footwear and apparel. "We believe NKE remains the key brand that wholesale customers shift orders to in times of distress and should also benefit from its superior sourcing capabilities, with a vertically integrated supply chain and more consolidated supplier base," the firm said. Bank of America did, however, reduce its EPS estimates for the company, and lowered its target to $85 from $105. The new target is 20% above where the stock currently trades. Shares of Nike have lost 30% this year. — Stevens

8:53 am: Uber jumps 9% as Wells Fargo upgrades stock to overweight, says stock can double

Shares of Uber jumped more than 9% during Friday's premarket trading after Wells Fargo upgraded the stock to an overweight rating. The firm said that after the stock's 45% decline since early February, shares are "attractively priced." "We think Uber's value remains tied to growth trends that will play out long after coronavirus-driven disruptions have subsided," the firm said, adding that consumers' shift from car ownership to ridesharing should continue to benefit the company. Wells Fargo's $41 target is 100% above where the stock currently trades. — Stevens

8:46 am: Roller coaster stretch for stocks

Stocks have whipsawed over the past two weeks, as uncertainty around the coronavirus worried investors. Thursday's gain of 0.5% was the smallest move for the S&P 500 in at least the past nine trading days. — Fitzgerald

8:05 am: Stocks hardest hit on coronavirus shutdown worries bouncing

Many battered travel companies were rebounding sharply in premarket trading Friday. United Airlines and American Airlines climbed 12% and 6%, respectively, after tanking 65% and 45% in March alone due to diminished demand for travel amid the coronavirus outbreak. Casinos MGM Resorts and Wynn Resorts rose 13% and 10%, respectively in premarket trading, while Marriott and Hilton also traded up more than 5% each. Many of these casinos and hotels were forced to shut down amid the pandemic. The travel and tourism industry is seeking $150 billion in financial aid, with the U.S. airline industry asking government aid of more than $50 billion. — Li

7:59 am: If the S&P closes positive today it would be the first 2 consecutive days of gains in more than a month

If the S&P closes positive today it would be its first 2 consecutive days of gains in more than a month, back to Feb 12 and its 3-day win streak If the Dow closes positive today it would be its first 2 consecutive days of gains in more than a month, back to Feb 6 and its 4-day win streak If the Nasdaq closes positive today it would be its first 2 consecutive days of gains in a month, back to Feb 19 and its 3-day win streak The Russell 2,000 closes positive today it would be its first 2 consecutive days of gains in a month, back to Feb 20 and its 2-day win streak — Francolla, Fitzgerald

7:41 am: GOP senators face questions over stock sales before market plunge

Republican Senators Richard Burr of North Carolina and Kelly Loeffler of Georgia are facing questions over their decision to sell large equity holdings before global markets began a historic plunge thanks to the spread of the novel coronavirus. Burr, chairman of the Senate Intelligence Committee, sold somewhere between $630,000 and $1.7 million worth of stock while Loeffler disclosed a string of sales that began on Jan. 24, the same day her committee hosted a private briefing about the virus. In the three weeks after Jan. 24, Loeffler and her husband, Jeffrey Sprecher, sold shares worth between $1.25 million and $3.1 million, according to government records. Sprecher is chairman of the New York Stock Exchange and chairman and CEO of its holding company International Exchange. — Franck, Wilkie

7:40 am: Coronavirus update: Global death toll tops 10,000, California issues stay home order

The global death toll from the coronavirus pandemic has risen above 10,000, according to data from Johns Hopkins University. On Thursday, Italy overtook China to be the world's deadliest hot spot with 3,405 deaths registered. Meanwhile, California Gov. Gavin Newsom on Thursday issued a statewide order for all residents to "stay at home" amid a coronavirus outbreak. The stay home order is in place till further notice. — Li

7:37 am: Oil prices extend gains, bouncing 5%

Oil extended gains on Friday, one day after surging more than 23% in its best day on record. U.S. West Texas Intermediate crude jumped 4.6% to $26.39 per barrel, while international benchmark Brent crude gained 3.4%. Traders are hoping that stimulus measures announced worldwide will help curb the economic slowdown caused by the coronavirus. Recent gains notwithstanding, WTI is still on track for its worst month on record. — Stevens

7:35 am: Tech stocks jumping again

Shares of technology companies such as Microsoft and Nvidia, up more than 4% each, climbed in premarket trading. The rise came as the tech-heavy Nasdaq Composite headed for its second day gains, with Nasdaq-100 futures jumping almost 5%. The five "FAANG" stocks -- Facebook, Apple, Amazon, Netflix and Google-parent Alphabet— all rose as well. —Sheetz

7:34 am: Dollar weakens after soaring this week

The dollar index fell on Friday, weakening 0.6% to 102.16 after central bank actions. Still, the U.S. dollar is up about 3.5% this week against a basket of currencies as investors seek safety and liquidity in the world's reverse currency. At its three-year peak of nearly 103 hit overnight, the dollar was up more than 5%, its biggest weekly gain since October 2008. A strong dollar is difficult for U.S. exporters during this time of economic uncertainty. A weaker dollar makes it cheaper for people overseas to buy U.S.-made products, which helps U.S. companies. — Fitzgerald

7:10 am: Stocks set to rise, Nasdaq futures hit 'limit up'