<p>Economies thrown into renewed turmoil as AI debt, Iran war and soaring government bond yields fuel alarm</p><p>At the height of the summer, the mood was optimistic in the world’s financial capitals. Powered by the <a href="https://www.theguardian.com/technology/artificialintelligenceai">AI revolution</a>, the US stock market had rallied to a <a href="https://www.theguardian.com/business/2026/aug/04/stock-market-records-ai-profits-oil-prices-ease">fresh all-time high</a>, as investors bet the