NEW YORK (AP) — Stocks plunged again Thursday, and for the second time in four days the Dow Jones industrial average sank more than 1,000 points.

The two best-known stock market indexes, the Dow and the Standard & Poor’s 500, have dropped 10 percent from their all-time highs, set Jan. 26. That means they are in what is known on Wall Street as a “correction,” their first in almost two years. Stocks fell further and further as the day wore on and suffered their fifth loss in the last six days. Many of the companies that led the market’s gains over the last year have struggled badly in the last week. Those included technology companies, banks, and retailers and travel companies and homebuilders.