The S&P 500 was down 0.7% in midday trading to 2,146.53.
The Dow Jones Industrial Average was down 0.7% to 18,124.04.
The NASDAQ was down 0.4% to 5,278.58.
The yield on a 10-year Treasury bond rose 3.6% to 1.68%.
The price of gold fell 3.1% to $1,273.
Irvine-based Biolase Inc. was down 14% to $1.48 and an $87 million market cap on high volume. The dental laser maker had traded shares by midday at a rate double its 90-day average. Biolase’s share price more than doubled in the last 90 days but are down 20% from that peak over the last two weeks.
Costa Mesa-based Cerebain Biotech Corp. was up 15% to 83 cents and a $5.5 million market cap on higher-than-average volume. The company is working on drugs and medical devices to treat Alzheimer’s disease.