On May 15, 2026, a divergence that had been building for weeks reached a visible breaking point. US benchmark 10-year Treasury yields hit their highest level in approximately a year, two days after the government sold 30-year bonds at the highest yield since 2007. Brent crude climbed 3.37% on the same day to $109.30 per barrel. The Nasdaq fell 1.54%. One day earlier, the Dow Jones Industrial Average had reclaimed the 50,000 mark for the first time, and the S&P 500 had briefly traded above 7,500.
The contradiction is stark. Stock markets surged back to record highs in the month-and-a-half since the Iran conflict's most acute phase in late March, driven by AI-linked earnings momentum from technology companies. Bond markets, meanwhile, have been pricing in a grimmer trajectory — one where the Fed is forced to keep rates elevated longer than previously expected, or potentially raise them, to contain energy-driven inflation. US 10-year real yields (inflation-adjusted TIPS) hit 2.083%, reinforcing the view that the Fed can afford to stay on hold and that the bond selloff may have further to run.
Goldman Sachs data showed hedge funds had bought a record $86 billion in stocks over five sessions in mid-May, driven mainly by systematic, trend-following strategies. The surge was described as among the fastest on record, fuelled partly by easing geopolitical tensions from the Trump-Xi summit and partly by AI earnings momentum. Goldman estimated funds could add another $70 billion if momentum continued. Yet many institutional investors were simultaneously raising flags about the disconnect between equity valuations and underlying economic fundamentals.
The Financial Stability Board issued a separate warning: the Middle East conflict is creating significant global financial instability through stretched asset valuations, high leverage in parts of the non-bank financial sector, and liquidity mismatches. These vulnerabilities, the FSB noted, could amplify future shocks and threaten sovereign bond markets, private credit, and broader financial stability if conditions worsen. For investors, the message from bond markets is a cold shower on the equity rally's temperature.
