US Treasury yields have defied their traditional safe-haven role during geopolitical turmoil, climbing toward 4.5 per cent even as the S&P 500 plunged nearly 8 per cent after US strikes on Iran. This unusual market behavior reflects growing inflation concerns as oil prices remain elevated, prompting investors to demand higher yields despite heightened global uncertainty.

Jim Reid at Deutsche Bank suggests the conflict could drive increased fiscal spending on defense and energy independence, putting further pressure on bonds relative to equities. NYU Stern researchers Viral Acharya and Toomas Laarits have documented a significant decline in the convenience yield for long-dated Treasuries since last spring's tariff war chaos, causing these securities to behave more like stocks and eroding their traditional hedging properties.

The implications are profound for both investors and the US government. If Treasuries continue losing their special status as the world's premier safe asset, portfolio construction strategies may need fundamental revision, and the government could face higher borrowing costs. The shift suggests markets are increasingly pricing in persistent inflation risks and structural changes to global financial dynamics.