The Yen's Hidden Backstop: FIMA, Dollar Creation and the Treasury Market

Japan's 2026 yen intervention was enormous, but Federal Reserve balance-sheet data show FIMA was not used to fund it. That may be the more important finding. FIMA sits behind the global dollar system as a mechanism allowing approved foreign monetary authorities to temporarily turn U.S. Treasury collateral into newly supplied dollars instead of selling those Treasuries into the market. This report examines what FIMA actually does, why it is a form of temporary central-bank dollar creation rather than QE, what Japan's reserve structure looks like, and why another serious yen crisis could migrate directly into U.S. Treasury-market plumbing.