The S&P 500 was down 0.6% in midday trading to 2,065.06
The Dow Jones Industrial Average was down 0.8% to 17,585.68.
The Nasdaq was down 0.1% to 5,097.78.
The yield on a 10-year Treasury bond was down 0.4% to 2.22%.
The price of gold was down 0.1% to $1,074.
Irvine-based Impac Mortgage Holdings Inc. was down 7% to $18.28 and a $189 million market cap on above-average volume.
Irvine-based ChromaDex Corp. was down 8% to $1.17 and a $128 million market cap on high volume.