The S&P 500 was down 0.10% to 1,753.39 in afternoon trading Wednesday.
The Dow Jones Industrial Average rose 0.04% to 15,451.73, while the Nasdaq fell 0.31% to 4,018.97.
The yield on a 10-year Treasury bond was up 1.71% to 2.67%.
The price of gold rose 0.36% to $1,255.70 per ounce.
Irvine-based heart valve maker Edwards Lifesciences Corp. rose about 2% to $67.12 after the company said its Sapien XT heart valve received European approval for use with certain procedures. Edwards had a recent market value of $7.34 billion.
Newport Beach-based Clean Energy Fuels Corp. was off about 11% to $10.29, trading on unusually high volume of about three times its average. Clean Energy had a recent market value of $91.49 million.
Santa Ana for-profit school operator Corinthian Colleges Inc. was off about 7% to $1.31 for a market value of $114.03 million. The company reported results for its December quarter and a higher-than-expected decline in new student enrollment. Corinthian had a recent market value of $114.03 million.
Foothill Ranch-based teen and contemporary retailer Wet Seal Inc. slipped about 7% to $2 for a market value of $169.44 million. The company said this week that Mindy Meads resigned from the board to focus on her duties as chief executive of retailer Calypso St. Barth.