Why markets really are less certain than they used to be

Market commentators and investors often exaggerate the uniqueness of their times. History counts no fewer than four “Black Mondays”—echoing the “Black Thursday” that sparked the 1929 Wall Street crash, which heralded the Great Depression—even though the 1987 and 2015 editions rapidly proved unremarkable. Many other days once doused in dark paint have been forgotten. The 25-year period to 2007 looks so boring, in hindsight, that it is dubbed the “Great Moderation”. The ensuing financial crisis did rock markets, but the pattern of hyped but transitory shocks soon resumed—remember the taper tantrum of 2013?