"People are overreacting a little bit," said Gene Goldman, head of research at Cetera Financial Group. "It goes back to the fundamentals, the economy is improving."
The Dow's drop Thursday—which knocked the average down 2.3 percent to 14,758.32—was its biggest since November 2011. It comes just three weeks after the blue-chip index reached an all-time high of 15,409. The index has lost 560 points in the past two days, wiping out its gains from May and June
The S&P 500 lost 40.74 points, or 2.5 percent, to 1,588.19. It also reached a record high last month, peaking at 1,669. The Nasdaq composite fell 78.57 points, or 2.3 percent, to 3,364.63.
Small-company stocks fell more than the rest of the market Thursday, a sign that investors are aggressively reducing risk. The Russell 2000 index, which includes such stocks, slumped 25.98 points, or 2.6 percent, to 960.52. The index closed at a record high of 999.99 points Tuesday.
The yield on the 10-year Treasury note rose to 2.42 percent, from 2.35 percent Wednesday. The yield, which rises as the price of the note falls, surged 0.16 percentage point Wednesday after the Fed's comments. As recently as May 3, it was 1.63 percent.
A Fed policy statement and comments from Chairman Ben Bernanke started the selling in stocks and bonds Wednesday.
Bernanke said that the Fed expects to scale back its massive bond-buying program later this year and end it entirely by mid-2014 if the economy continues to improve.
The bank has been buying $85 billion a month in Treasury and mortgage bonds, a program that has made borrowing cheap for consumers and business. It has also helped boost the stock market.
Alec Young, a global equity strategist at S&P Capital IQ, said investors weren't expecting Bernanke to say the program could end so quickly, and are adjusting their portfolios in anticipation of higher U.S. interest rates.
"What we're seeing is a pretty significant sea-change in investor strategy," Young said
For much of the year, the stock market rose with barely an interruption. The S&P 500 climbed for seven months straight from November 2012 through May. Investors, fearful of missing out on the rally, pounced on any dips and pushed markets to record highs. On Thursday, those opportunistic buyers were absent. Nobody wanted to stand in the way of the market's slide.
As investors sold stocks, they likely put the proceeds in cash "for fear the deterioration will continue," said Quincy Krosby, a market strategist at Prudential Financial.
The sharp increase in bond yields prompted investors to sell homebuilders, whose business could be hurt if the pace of home buying slows down. Those stocks fell Thursday even though the National Association of Realtors said U.S. sales of previously occupied homes last month topped 5 million at an annual rate for the first time in 3 1/2 years.
PulteGroup plunged $1.89, or 9.1 percent, to $18.87. D.R. Horton fell $2.13, also 9.1 percent, to $21.31.
(Read More: Fed Shakes Global Markets as Interest Rates Rise)