The Standard & Poor's 500 Index declined for the fourth time in five sessions, as biotechnology shares tumbled while media companies sold off on disappointing results from Viacom Inc. and Twenty-First Century Fox Inc.
The S&P 500 lost 0.8 percent to 2,083.79 at 4 p.m. in New York, falling below its average prices during the past 50 and 100 days.
Media shares were battered for a second day, with quarterly earnings at CBS and Fox marked by shrinking U.S. ad sales and profits propped up by stock buybacks. Viacom, owner of MTV, Nickelodeon and Comedy Central, posted a third-quarter revenue decline that was wider than analysts had forecast.
Media stocks have been the darlings of the U.S. bull market that began 6 1/2 years ago. Since global equities bottomed in March 2009, the 15-member S&P 500 Media Industry Index has risen 464 percent, second only to automakers. Within the gauge, CBS and Tegna Inc. -- up more than 15 fold over the period -- are among companies with the 20 biggest gains.
About 85 percent of S&P 500 members have released earnings figures, with three-quarters beating profit estimates and half topping sales projections. Analysts now call for a 2.8 percent drop in second-quarter earnings, shallower than July 10 estimates for a 6.4 percent fall.
Along with corporate earnings, investors are also watching economic reports to gauge when the Fed will increase interest rates. A report today showed jobless claims rose by 3,000 to 270,000, hovering near four-decade lows as employers hold on to more workers in response to increased demand following a slump in early 2015.
Friday's monthly payroll data will be parsed for indications on the likelihood of a September rate increase, with a particular interest in any signs of stronger wage growth. The government's report is projected to show employers took on 225,000 workers last month, while the jobless rate held at a seven-year low of 5.3 percent.
The S&P 500 snapped a three-day losing streak Wednesday amid better-than-expected earnings from technology companies. The gauge is coming off its best monthly gain since February, and closed Thursday 2.2 percent below its record set in May.