The number of U.S. exchange-traded funds has nearly tripled in the past 10 years. One particular aspect of ETFs has reached “the highest ever” level — and if history is a guide, investors should take note.
The number of U.S. exchange-traded funds has nearly tripled in the past 10 years. One particular aspect of ETFs has reached “the highest ever” level — and if history is a guide, investors should take note.