S&P rose 0.8% to 3,470.16 in midday trading.
The Dow Jones Industrial Average was up 0.1% to 28,266.26, while the Nasdaq jumped 1.5% to 11,636.55.
Crude oil was flat at $43.35 a barrel.
Gold increased 1.5% to $1,952 an ounce.
The yield on a 10-year Treasury rose 4.3% to 0.705%.
Shares of Alteryx Inc. (NYSE: AYX) jumped 9.3% to $119.17 and a $7.9 billion market cap. Volume of 3.9 million shares was twice the normal daily average. It’s the biggest increase since the shares sank 28% Aug. 7 after the Irvine data analytics software maker warned of “significant headwinds” to the company’s business in the coming quarters.
San Clemente-based Glaukos Corp. (NYSE: GKOS) jumped 6.1% to $43.19 and a $1.9 billion market cap. Shares of the glaucoma drug and device maker are up about 85% since their 52-week low in March.