BIS chief Pablo Hernandez warned that the surge in debt-financed artificial intelligence spending could jeopardize financial stability if expected returns fail to materialize. He noted that the five biggest tech firms plan to allocate over $1 trillion to AI projects in 2025‑2026, with worldwide AI investment projected to reach $3‑$4 trillion by 2030. Hernandez drew parallels to past speculative booms — such as the 1830s canal mania, the 1840s British railway frenzy, the 1920s electrification wave and the late‑1990s dot‑com bubble — emphasizing that each eventually corrected with broad economic repercussions. He highlighted that chipmakers, hyperscalers and AI firms are intertwined through financing structures that are often opaque and hard to value, leaving the system vulnerable if profit expectations fall short. A downturn in heavily concentrated AI equities could curb consumer spending and, given the outsized weight of U.S. stocks in global markets, transmit the shock worldwide. While acknowledging AI’s genuine productivity gains in areas like coding, consulting and professional writing, Hernandez stressed that the ultimate economic impact will hinge on how widely those benefits are shared and whether policymakers invest in skills, infrastructure and competition. He added that AI does not alter central banks’ mandates, though it may complicate the interpretation and monitoring of the global economy.