The S&P 500 was down 0.4% in midday trading to 2,159.13.
The Dow Jones Industrial Average was down 0.1% to 18,519.56.
The NASDAQ was down 0.5% to 5,030.40.
The yield on a 10-year Treasury bond was down 2.3% to 1.55%.
The price of gold was up 0.3% to $1,333.
Foothill Ranch-based Kaiser Aluminum Corp. was down 5% to $88.97 and a $1.6 billion market cap. The metals manufacturer is scheduled to report earnings tomorrow after markets close. Kaiser competitor Aloca Inc. in New York earlier this month reported declining profits due to oversupply in the raw aluminum market.
Irvine-based Lantronix Inc. was up 7% to $1.23 and a $19 million market cap on high volume. The computer networking products maker had traded about 170,000 shares by midday, compared with a 90-day average of about 13,000.