The S&P 500 was up 0.4% in midday trading to 2,889.45.

The Dow Jones Industrial Average was up 0.5% to 25,997.84.

The Nasdaq was up 0.5% to 7,966.84.

The yield on a 10-year Treasury bond rose 1.1% to 2.97%.

The price of gold was 0.1% higher to $1,201.

HEALTHCARE

ChromaDex (Nasdaq: CDXC) fell 8% to $3.52 and a $193 million market cap. Shares of the Irvine-based maker of ingredients for nutritional supplements are down about 20% since Sept. 6, the day before the SEC charged billionaire investor Phillip Frost and associates with “pump and dump” stock promotion schemes. Frost has about a 6% stake in Chromadex and the company last year appointed Steven Rubin, an executive of Miami-based The Frost Group LLC, to its board. A ChromaDex spokesperson said via email the company isn't one of the companies in the SEC allegations.

MANUFACTURING

Irvine-based Pro-Dex Inc. (Nasdaq: PDEX) rose 5.8% to $10 and a $43 million market cap. Trading volume in the thinly-exchanged contract manufacturer is more than double its daily average. It hit a 52-week high of $11 on Sept. 6.