The S&P 500 was up 0.6% in midday trading to 2,016.90.
The Dow Jones Industrial Average was up 0.5% to 17,214.01
The NASDAQ was up 0.7% to 4.957.91.
The yield on a 10-year Treasury bond was down 0.4% to 2.19%.
The price of gold was up 1.4% to $1,080.
Newport Beach-based natural gas fueling station operator Clean Energy Fuels Corp. was down 3.7% to $3.36 and a $304 million market cap as oil prices hit an 11-year low.
Santa Ana-based collectibles authenticator Collectors Universe Inc. was up 3.8% to $16.41 and a $145 million market cap on above-average volume.