Benchmarks fell in Asia, with South Korea’s Kospi dropping nearly 4% after the tariff rate for the U.S. ally was set at 15%. The U.S. dollar weakened against the Japanese yen, trading at more than 150

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.