A global reshuffling in stock-market hierarchy is underway, with artificial intelligence redrawing the pecking order of equity markets and propelling Taiwan and South Korea past several long-established Western bourses. Taiwan has overtaken Canada to become the world's sixth-largest stock market, while South Korea has leapfrogged the U.K. into eighth place, according to HSBC data tracking global equity-market capitalization rankings. It's the latest demonstration of how the AI boom is