The S&P 500 was down 0.5% to 2,097.40 in midday trading.

The Dow Jones Industrial Average was down 0.6% to 18,095.36 and the Nasdaq was down 0.3% to 4,967.02.

The yield on a 10-year Treasury bond rose 0.1% to 2.12%

The price of gold fell 0.3% to $1,201.

RETAIL

Huntington Beach-based Quiksilver Inc. was down 8.5% to $1.82 and a $311.5 million market cap. The surf apparel manufacturer said it would delay its quarterly earnings release scheduled for tomorrow because of a “revenue cut-off issue.” The company said it didn’t expect changes to previous financial results or its future guidance, and would provide an update later this month.

HEALTHCARE

Irvine-based AtheroNova Inc. was down another 26% to less than two cents a share and a market cap below $200,000. Shares in the company fell by more than half yesterday after it filed for bankruptcy protection.