It’s Halloween, so what else could we do but write about what might scare the markets? We know from the financial media, measures of investor sentiment, and mutual fund outflows from equities and into bonds that investor nervousness is widespread. Some concerns are related to the presidential election, now just eight days away. Other concerns are related to the age of the bull market, discomfort with central bank actions, Brexit, and China’s debt problems; and there are certainly others. This week, in the spirit of Halloween, we discuss what might scare markets.