Matt Levine’s Money Stuff: Everything Is an ETF Now

Autocallable ETF

There is a market for insurance against stock market crashes. Most investors are more or less long the stock market — they own diversified portfolios of stocks — and some of them worry that they will lose money if the stock market goes down. They would like to buy long-term black-swan-type insurance against a disastrous market crash.

But who wants to sell that insurance? Well, Warren Buffett, occasionally. But in general, this sort of insurance is not that appealing for the seller: The trade is “you get paid a little bit each year when times are good, but you ...