The S&P 500 rose 0.39% to 1,769.89 in afternoon trading Wednesday.
The Dow Jones Industrial Average was up 0.72% to 15,730.92, while the Nasdaq was off 0.26% to 3,929.68.
The yield on a 10-year Treasury bond was down 0.75% to 2.64%.
The price of gold rose 0.69% to $1,317.10 per ounce.
Newport Beach chipmaker Mindspeed Technologies Inc. surged about 68% to $5, a day after the company said it would be sold for $272 million to Massachusetts competitor M/A-COM Technology Solutions Holdings Inc. Mindspeed had a recent market value of $216.95 million.
Aliso Viejo-based chipmaker Microsemi Corp. shares were up about 4% to $25.08 for a market value of $2.34 billion. The company is expected to report its fourth-quarter and full-year earnings on Thursday.
Lake Forest-based Quantum Fuel Systems Technologies Worldwide Inc. shares were up about 12% to $4.65 for a market value of $69.54 million. The company said Monday it inked $3.2 million in new orders for Arizona-based ZHRO Solutions LLC. Quantum Fuel's shares have risen about 44% since the start of the year.