The S&P 500 was up 0.26% to 1,849.96 in afternoon trading Thursday.
The Dow Jones Industrial Average rose 0.26% to 16,240.58, and the Nasdaq rose 0.38% to 4,308.51.
The yield on a 10-year Treasury bond fell 1.16% to 2.64%.
The price of gold was up 0.47% to $1,334.20 per ounce.
Anaheim drug maker Questcor Pharmaceuticals Inc. was off about 8% to $68.41 following the release of a negative report by short seller Citron Research related to Questcor's core H.P. Acthar Gel drug. The company had a recent market value of $4.03 billion.
Irvine-based TRI Pointe Homes Inc. was up about 5% to $19.33 after reporting better-than-expected fourth-quarter results before market opening Thursday. The homebuilder had a recent market value of $610.77 million.