Bets against exchange-traded funds have hit multiyear highs as some investors question whether this industry—which grew rapidly in the bull market—could handle sudden redemptions in a downturn. Investors are shorting the shares of some ETFs that buy securities like high-yield debt, which may be hard to sell if markets turned suddenly, a fear stoked by increased volatility this year.

Source: Wall Street Journal March 21, 2018 10:18 UTC