The S&P 500 was up 0.4% in midday trading to 2,107.72.
The Dow Jones Industrial Average was up 0.4% to 18,043.85.
The Nasdaq was up 0.7% to 5,108.07.
The yield on a 10-year Treasury bond was down 1% to 2.4%.
The price of gold was down 0.1% to $1,154.
Newport Beach-based Clean Energy Fuels Corp. was up 10% to $6.78 and a $613 million market cap. The natural gas fueling station operator said last week it was on track to build 36 station this year and shares have climbed 30% in the five trading sessions.
Anaheim-based Willdan Group Inc. was up 5.6% to $11.09 and an $87 million market cap. The engineering and technical services consultant said it signed a $7.5 million contract with a Southern California utility to help small businesses reduce energy use.