Viewers of “The Big Short”, a film released in 2015, based on a book by Michael Lewis, might remember the travails of investors who sought to short-sell American housing debt in the run-up to the collapse of Lehman Brothers. A growing number of investors now fear that America could be in for a jolt of a similar type, if not scale. And it could emerge, they think, from private markets and unlisted corners of the tech industry.Explore moreOpinionColumnsButtonwoodStocksFinance & economicsThe Econom...