Jittery investors dump stocks

Stocks tumbled Tuesday morning, as jittery investors dumped shares ahead of the start of the G8 summit and the second-quarter corporate reporting period.

The Dow Jones industrial average (INDU) lost 80 points, or 1% roughly 90 minutes into the session. The S&P 500 (SPX) index lost 8 points, or 0.9% and the Nasdaq (COMP) fell 18 points, or 1%.

Stocks were mixed Monday as investors drifted back in after the long holiday weekend. Stocks have been inching lower since mid-June as a three-month stock market rally has lost steam.

The S&P 500 spiked 40% on bets that the economy is stabilizing, but a recent bout of mixed news has stalled the advance, culminating with last week's weaker-than-expected June jobs report.

Economic news due later this week includes readings on retail sales, the job market, import and export prices and consumer sentiment.

Investors are also primed for the start of the second-quarter reporting period, which unofficially kicks off after the close Wednesday with Dow component Alcoa. The aluminum maker is expected to post a loss of 37 cents per share, according to Thomson Reuters estimates. Alcoa earned 65 cents a year ago.

However, most quarterly financial reports are due out later in the month. Market participants will be looking to see not only that companies beat forecasts, but that they provide an encouraging outlook for future quarters.

Also in focus: The G8 summit of the world's leading industrialized nations, beginning Wednesday in L'Aquila, Italy. President Obama is expected to speak about the economic outlook. Leaders of Japan, Britain, France, Italy, Germany, Canada and Russia will also speak.
0:00 /1:12The G8's new guest list

Bonds: Treasury prices rose, lowering the yield on the benchmark 10-year note to 3.51% from 3.52% late Thursday. Bond markets were closed Friday. Treasury prices and yields move in opposite directions.

Other markets: In global trade, Asian markets tumbled and European markets were mixed in the afternoon.

Energy prices tumbled, with U.S. light crude oil for August delivery falling 97 cents to $63.08 a barrel on the New York Mercantile Exchange.

In currency trading, the dollar fell versus the euro and the yen.

COMEX gold for August delivery fell 80 cents to $923.50 an ounce.

Market breadth was negative and volume was light. On the New York Stock Exchange, decliners beat advancers five to two on volume of 250 million shares. On the Nasdaq, losers topped winners three to two on volume of 580 million shares.