The S&P 500 was up 0.8% in midday trading to 2,039.04.
The Dow Jones Industrial Average was up 0.8% to 17,385.57.
The Nasdaq was up 0.4% to 4,949.51.
The yield on a 10-year Treasury bond was down 0.7% to 2.26%.
The price of gold was up 0.3% to $1,084.
Irvine-based Sabra Health Care REIT Inc. was down 1.2% to $18.96 and a $1.2 billion market cap. Analysts at Stifel Nicolaus downgraded shares in the health facilities operator to “hold.”
Newport Beach Alliance Healthcare Services Inc. was down 13.2% to $7.96 and an $84 million market cap. The operator of radiology and oncology clinics had traded shares at about double its average by midday.
Irvine-based Netlist Inc. was up 16.7% to 59 cents and a $30 million market cap. The storage products maker said a federal appeals court “upheld the validity of all claims” in a patent dispute with Westlake Village-based Inphi Corp.
Irvine-based Boot Barn Holdings Inc. was down 10.3% to $9.89 and a $261 million market cap on above-average share volume. The western wear retailer reported disappointing quarterly numbers last week and its share price has fallen by one-third over the last four sessions.