Exchange-traded funds (ETFs)

"I don't think passive investing itself is a bad thing, and especially with ETFs. My main concern is whether investors are counting on their ETFs to be highly liquid, and whether they might be disappointed.

"If you found a buyer of a high-yield bond ETF, and you said, 'Why did you buy that?' He's going to say, 'The great thing is, I can get out any time.' But ... at what price?"