ReutersRepublican presidential candidate Donald Trump speaks on the USS Iowa in San Pedro, Los Angeles, California, United States September 15, 2015.

Stocks stumbled Friday after the Trump administration slapped China with hefty tariffs on billions of dollars worth of Chinese goods, prompting retaliation and stoking a trade battle between the world's largest economies. Crude oil slid ahead of next week's meeting among oil-supply-cutting countries. The dollar and Treasury yields struggled to find direction.

Here's the scoreboard:

2,778.01 −4.48 (-0.16%)

And a look at the upcoming economic calendar:

• European Central Bank President Mario Draghi speaks.
• Housing data and central bank meeting minutes are out in Australia.