The S&P 500 was up 0.4% in midday trading to 1,986.78.
The Dow Jones Industrial Average was up 0.2% to 16,988.11.
The NASDAQ was up 0.4% to 4,667.62.
The yield on a 10-year Treasury bond was up 3% to 1.89%.
The price of gold was down 0.5% to $1,257.
Orange County natural gas companies were up as oil prices approached $40 a barrel and natural gas futures rose.
Newport Beach-based Clean Energy Fuels Corp., which builds and operates natural gas fueling stations, was up 15% to $3.46 and a $313 million market cap. Lake Forest-based Quantum Fuel Systems Technologies Worldwide Inc., a manufacturer of natural gas fuel storage tanks, was up 8% to 80 cents and a $22 million market cap. Both companies traded shares by midday at a rate above their 90-day averages.