The S&P 500 was down 0.2% in midday trading to 2,728.24.
The Dow Jones Industrial Average declined 0.3% to 24,811.23.
The Nasdaq dropped 0.1% to 7,421.74.
The yield on a 10-year Treasury bond fell 0.7% to 2.98%.
The price of gold was up 1.2% to $1,305.
Glaukos Corp. (NYSE: GKOS) in San Clemente was up 2% to $35.66 and a $1.2 billion market cap. It makes medical devices to treat glaucoma.
Quality Systems Inc. (Nasdaq: QSII) in Irvine was up 2.2% to $14.95 and a $953 million market cap. It makes software to manage medical and dental practices.
ChromaDex Corp. (Nasdaq: CDXC) in Irvine was down 4.2% to $3.67 and a $201 million market cap. It makes nutritional ingredients and products.
Youth fashion retailer Tilly’s Inc. (NYSE: TLYS) in Irvine was up 2.8% to $11.99 and a $349 million market cap.