The S&P 500 rose 0.38% to 1,404 in midday trading Wednesday.
The Nasdaq was up 0.43% to 2,981, while the Dow Jones Industrial Average was up 0.60% to 12,955.
The yield on a 10-year treasury bond fell 1.64% to 1.62%.
The price of gold was off 1.5% to $1,716 per ounce.
Shares of Irvine-based healthcare software maker Quality Systems Inc. rose about 3% to $19 for a market value of $1.1 billion. Quality Systems subsidiary NextGen Healthcare Information Systems LLC said it has partnered with medical coding company Aviacode to offer NextGen customers access to Aviacode’s web-based coding system.
Newport Beach specialty chemicals maker American Vanguard Corp. fell about 3% to $33 for a market value of $935 million.
Santa Ana-based circuit board maker TTM Technologies Inc. rose about 3% to $9 for a market value of $714 million.