[NEW YORK] US stocks headed lower Tuesday as Alcoa began third-quarter earnings season with a disappointing report.
Alcoa slumped 7.9 per cent after earnings of 32 cents per share missed analyst expectations by a penny.
Analysts also cited a disappointing forecast for the aluminum specialist's value-added businesses, which will be renamed "Arconic" when the company splits in two on November 1.
About 10 minutes into trade, the Dow Jones Industrial Average stood at 18,263.33, down 0.4 per cent.
The broad-based S&P 500 lost 0.4 per cent at 2,154.92, while the tech-rich Nasdaq Composite Index shed 0.3 per cent to 5,312.16.
Apple jumped 2.1 per cent as rival Samsung Electronics scrapped production of its Note 7 smartphones following problems with exploding batteries.