There's a new theory in town.
Renowned economist Robert Shiller's new book suggests investors may be able to predict and prepare for economic events by tracking popular stories.
Applying the theory might have been a challenge last week. There were so many stories with potential to move markets and affect the economy it was difficult to guess which would be the most influential.
In the end, on-again-off-again trade negotiations provided the spark that drove markets lower. Barron's explained:
"The S&P 500 would have finished flat for the week - except it decided to drop 0.5 percent after reports that China had canceled a visit to Montana hit the newswires...That's not what we would have expected, given all of the week's excitement. Saudi Arabia's oil infrastructure was attacked. The Federal Reserve cut interest rates by a quarter-point. U.S. money markets went crazy and forced the Fed to intervene, setting off comparisons to the collapse of Lehman Brothers in 2008. And, yet, a Montana junket was the ultimate determinant of whether the market finished up or down."
On Saturday, reports from U.S. trade representatives and China's state-run news agency emphasized trade discussions were 'constructive' and 'productive' and would continue in October, reported The New York Times.
Last week, Federal Reserve Chair Jerome Powell mentioned trade wars 20 times in his news conference, reported The Wall Street Journal. "Other geopolitical risks figured less prominently or not at all. Mr. Powell mentioned Brexit once, and tensions in Hong Kong and Saudi Arabia didn't come up."
The Fed chair emphasized the Fed is using the tools at its disposal to support demand and counteract economic weakness. However, it has no way to resolve trade issues. He pointed out uncertainty about trade has reduced business investment across the United States and could hurt economic growth.
Until an agreement is reached, stories told about U.S.-China trade issues are likely to remain influential.
