Governments issue bonds when taxes do not cover spending. Buyers get principal and interest unless the state defaults, so these are treated as the safest asset and their yield anchors every other rate, from mortgages to corporate debt. When a foreign central bank dumps them, the issuing country's long-term rates get pushed up.
Awaiting gradingOn July 31 the New York Fed sold euros to buy yenScore on the Fed's H.4.1 released August 6 (as of August 5): dollars borrowed by foreign monetary authorities against Treasuries moving off zero counts as the FIMA route opening, staying at zero counts as the original expectation missing.
HitThe market didn't lose $900 billion to the Iran war on July 23. It lost $797 billion to AI-capex fearsBy July 29, 2026 the AI-capex-driven selloff had deepened rather than recovered: the Nasdaq 100 fell into correction territory (down over 10% from its June record) and the VanEck semiconductor ETF dropped for a fourth straight session, confirming AI-capex fears -- not the Iran war -- kept driving the market, as the original piece had argued.