The S&P 500 was up 0.8% in midday trading to 2,924.84.
The Dow Jones Industrial Average rose 1% to 26,229.82.
The Nasdaq climbed 0.9% to 8,020.82.
The yield on a 10-year Treasury bond was unchanged at 1.56%.
The price of gold was flat at $1,516 an ounce.
The price of oil was also flat at $56.13 a barrel.
Alteryx Inc. (NYSE: AYX) in Irvine was up 4.6% to $141.75 and a $9.2 billion market cap. Shares in the data analytics software maker are up 74% since early June.
Emerald Expositions Events Inc. (NYSE: EYX) rose 3.3% to $9.77 and a $704 million market cap. The San Juan Capistrano trade show producer and media firm has seen it shares fall about 40% since June. Moody’s this month noted Emerald’s B1 rating is “constrained by its highly cyclical business” but its credit is backed by its variety of trade show offerings and “free cash flow due to limited required capital” spending.