Investors signaled strongly on Thursday they're still not ready to return to equities.

The Dow Jones Industrial Average shed 1,033 points, or 4.15%, to snag its second-biggest single day point decline in history. It's biggest single-day decline was also this week, on Monday, Feb. 5. The blue-chip index is now in correction territory, down more than 2,700 points from its high of 26,616 set on Jan. 26.

The S&P 500 fell 3.75% to break below its 100-day moving average and close under the important 2,700-point threshold. The Nasdaq tumbled 3.9%, as well.

Here are three reasons why the stock market continues to nosedive this week.

Volatility Skyrockets

Volatility up, stocks down is the new trade in town. The Cboe Volatility Index shot higher 23% by the close of trading Thursday. In the past five days, the index, commonly regarded as Wall Street's fear gauge, has skyrocketed 154%.

Bond Yields Surge

Also throwing investors off stocks was the surge in bond yields again Thursday. Bond yields continue to trade near multi-year highs. The U.S. 10-year Treasury note yield rallied close to 2.9% in early trading -- the yield's four-year high is 2.885%. By the closing bell, the note was yielding about 2.83%.

Earnings Not Enough

A number of big-name companies reported earnings beats on Thursday, but it wasn't enough to squash the general markets concerns ripping through Wall Street. Tesla Inc. (TSLA) shares fell despite the company's narrower-than-expected loss. T-Mobile US Inc. (TMUS) shares were also down despite an earnings beat. The same took place for both CVS Health Corp. (CVS) and Twenty-First Century Fox Inc. (FOXA) .

When solid earnings don't send stocks higher, it's often not a good sign of things to come.

Don't give up totally on the market. 

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