NEW YORK — Dejected investors sent stocks plunging yesterday, hurtling the Dow Jones industrials down more than 340 points after retailers and the government added to a mountain of bad economic news and devastated hopes for a late-year recovery.

The market was already nervous as it waited for the government to release its August employment report today. So news from the nation's major retailers that shoppers curtailed their spending last month due to higher gas and food prices came as a heavy blow.

Wal-Mart Stores Inc., the world's largest retailer, beat expectations because of its big discounts, but many teen retailers and luxury chains did poorly, a sign that consumers are spending mostly on essentials and putting discretionary buying on hold.

Meanwhile, the Labor Department said new applications for unemployment insurance rose by 15,000 last week from the previous week. That missed expectations for a fourth-straight week of declines, heightening worries that the average American — already feeling the effects of the weak housing market — will have even less means to spend.

Furthermore, if the job market keeps deteriorating, it is tough for Wall Street to see a rebound in sight for the economy's biggest culprit: the tumbling housing market.

The numbers released yesterday were a sign that despite some upbeat reports over the past month, the economy remains deeply troubled. Investors are not expecting any promising news in the August jobs report, particularly after the ADP National Employment Report said that private sector employment decreased in August by 33,000. Economists are predicting the government will report the eighth straight monthly payrolls drop, and a rise in the unemployment rate.

The Dow fell 344.65, or 2.99 percent, to 11,188.23. It was the worst drop for the blue-chip index since June 26, when it fell more than 358 points, or 3.03 percent.

Broader indexes also tumbled. The Standard & Poor's 500 index fell 38.15, or 2.99 percent, to 1,236.83, and the Nasdaq composite index dropped 74.69, or 3.20 percent, to 2,259.04.

All three indexes moved back into bear market territory, defined as a 20 percent drop from a recent peak. The indexes were at highs, including a record 14,198.09 for the Dow, last October.