Leveraged funds, including those focused on single stocks, have exploded in number and popularity in recent years. The op-ed piece followed disastrous episodes of South Korean leveraged ETFs crashing as chip-maker stocks fell. Newer restrictions in that country have reportedly driven at least some traders to use US leveraged products. That could also include a point-of-sale message showing how a leveraged fund’s returns can diverge from those of individual stocks. “They’re probably inappropriate for retail investors, but they’re being heavily marketed to retail investors,” he said.