The S&P 500 was up 0.1% in midday trading to 2,576.70.
The Dow Jones Industrial Average rose 0.1% to 23,397.22.
The NASDAQ fell 0.4% to 6,698.00.
The yield on a 10-year Treasury bond declined 0.8% to 2.36%.
The price of gold climbed 0.5% to $1,277/
Clean Energy Fuels Corp. (Nasdaq: CLNE) was up 2.8% to $2.41 and a $365 million market cap. The operator of natural gas fueling stations announced new or expanded fueling contracts with USPS contract trucking firms in four states. Clean Energy now has deals with 15 such firms.
William Lyon Homes (NYSE: WLH) was up 3.7% to $28.77 and a $920 million market cap. Shares in the home builder and developer have risen about 15% in two days since a positively received quarterly report yesterday.
Willdan Group Inc. (Nasdaq: WLDN) was down 3.4% to $29.05 and a $254 million market cap. The engineering services firm plans to release quarterly results tomorrow.