But there is a non-statistical basis for concern: an ominous parallel with the financial environment that prevailed in the weeks leading up to the October 1987 stock-market crash. On that day — Black Monday — the Dow Jones Industrial Average dropped 22.6% in a single session.

U.S. President Donald Trump's new tariff rates of up to 41% on U.S. imports from dozens of countries have drawn expressions of relief from some countries that negotiated a deal or managed to whittle t