The S&P 500 was down 0.1% in midday trading to 2,295.14.

The Dow Jones Industrial Average was up 0.1% to 20,085.20.

The NASDAQ was down 0.1% to 5,650.34.

The yield on a 10-year Treasury bond fell 0.4% to 2.51%.

The price of gold fell 0.7% to $1,191.90.

HEALTHCARE

Irvine-based Aerie Pharmaceuticals Inc. was up 2% to $42.00 and a $1.4 billion market cap on moderate volume. The clinical-stage pharmaceutical company is developing a drug to lower internal eye pressure.

Quality Systems Inc. in Irvine was up 5% to $14.49 and an $900 million market cap. The maker of software for medical practice management reported earnings of $10.5 million on revenue of $127.9 million for its recent quarter. The earnings and revenue figures beat analysts’ expectations.

TECHNOLOGY

Costa Mesa-based TTM Technologies Inc. was down 2.9% to $14.72 and a $1.5 billion market cap on moderate volume.