The S&P 500 climbed 0.7% in midday trading to 2,733.15.
The Dow Jones Industrial Average jumped 1.3% to 25,023.16.
The Nasdaq increased 0.7% to 7,534.22.
The yield on a 10-year Treasury bond was flat at 3.07%.
The price of gold was down 0.2% to $1,289.
Alteryx Inc. (NYSE: AYX) in Irvine was up 5.4% to $32.51 and a $2 billion market cap. A KeyBanc analyst upgraded the shares of the analytics software maker today.
Endologix Inc. (Nasdaq: ELGX) in Irvine climbed 4.8% to $5.20 and a $437 million market cap on moderate volume. Shares of the maker of medical devices to treat abdominal aortic aneurysms are up 38% since a 52-week low in February.