The S&P 500 was up 0.5% in midday trading to 2,186.88.

The Dow Jones Industrial Average was up 0.7% to 18,629.54.

The NASDAQ was up 0.6% to 5,233.02.

The yield on a 10-year Treasury bond was up 3% to 1.55%.

The price of gold was up 0.4% to $1,349.

HEALTHCARE

Irvine-based ChromaDex Corp. was up 3.6% to $4.38 and a $166 million market cap. The ingredients maker is scheduled to report results after markets close today.

RETAIL

Irvine-based Boot Barn Holdings Inc. was up 5.3% to $11.09 and a $292 million market cap on moderate volume. The company operates a chain of western wear stores.