What happens if investors become fearful?

With the stock market reversing course on Wednesday, going from up near 10 points on the S&P 500 to down more than 14 in early afternoon trading, what drives the market’s increasingly schizophrenic movements could be more than just the excuse du jour.

Today’s market decline is being pegged on some sources.

CNBC is reporting that the Trump administration is considering ramping up a trade war with China, imposing investment restrictions, indefinite tariffs and potentially restrictions on Chinese travelers. Concerns are that China may retaliate on US companies, notably Boeing, which was down near 3% at...