The S&P 500 fell 0.7% to 3,222.32 in midday trading Friday.
The Dow Jones Industrial Average was off 1.1% to 26,023.31, while the Nasdaq was down 0.2% to 10,570.76.
Crude oil slipped 0.2% to $39.84.
Gold rose 1.1% to $1,988.80.
The yield on a 10-year Treasury bond was up 1.3% to 0.55%.
NextGen (Nasdaq: NXGN) shares popped 13.6% to $14.24, a day after reporting better-than-expected results for its fiscal first quarter ended June 30. The Irvine-based medical software maker had a recent market cap of $950.3 million.
Shares of Costa Mesa-based El Pollo Loco Holdings Inc. (Nasdaq: LOCO) ran up 9.2% to $18.76 for a market cap of $659.3 million. The grilled chicken chain yesterday reported second quarter results that beat analysts’ earnings and revenue consensus estimates.