Stocks down again at midday

NEW YORK -- Stocks are down again on Wall Street, this time because of the prospect of weaker earnings for Alcoa and Chevron.

Just before the lunch hour, the Dow Jones industrial average is down 67 points at 13,406. The Standard & Poor's 500 index is down three at 1,437. And the Nasdaq composite index is off three at 3,061.

This would be the third down day in a row for the Dow and the fourth for the S&P.

Alcoa, the aluminum company, beat Wall Street earnings estimates on Tuesday night but cut its demand expectation for the year, mostly because of a slowdown in China. Chevron says slumping oil prices and production will hurt its earnings.