U.S. Sells Euro to Support Yen, Catching ECB Off Guard as Western Central Bank Coordination Norms Break Down
Miles Bennett
The U.S. sold euros and bought yen in an FX intervention last week, notifying the ECB only after the trades were done — breaking decades of prior-consultation protocol among Western central banks and raising the question of whether the euro is now fair game in Washington's currency toolkit.
What did the U.S. actually do, and why was the ECB caught off guard?
The New York Fed, acting for the U.S. Treasury, sold euros and bought yen using the Exchange Stabilization Fund (ESF) — a Treasury-controlled reserve pool. The ECB learned about it only after the trades settled.
This means → Washington did not use its own currency to intervene. It moved someone else's currency without asking first.
Since World War II, the unwritten rule among Western monetary authorities has been "consult first, act together." ECB President Christine Lagarde spoke with Treasury Secretary Scott Bessent only after the fact.
Why sell euros instead of dollars?
Analysts say selling dollars to buy yen would have been read as deliberately weakening the dollar — directly contradicting Bessent's stated strong-dollar stance.
In plain terms = selling euros was a detour — same result for the yen, but the dollar never appeared on the sell ticket, keeping the political optics clean.
The Treasury's official line: ESF reserve-asset allocation decisions are made unilaterally, with no coordination with foreign authorities.
Why did the U.S. and Japan team up to support the yen at all?
This was the first coordinated U.S.–Japan yen purchase in nearly 30 years, pushing the yen from close to ¥164 per dollar — a near-40-year low — to roughly ¥158.
Economists suspect a second motive: preventing Japan from dumping U.S. Treasuries at a time when long-term U.S. borrowing costs were near a 19-year high.
This means → on the surface, Washington helped Tokyo defend its currency. Underneath, it was protecting the U.S. bond market from its largest foreign holder.
Can the Bank of Japan keep up with inflation pressure on its own?
BOJ Governor Kazuo Ueda held rates steady at the latest meeting but said he "needs to pay more attention to upside inflation risks than before."
Overnight-index-swap pricing currently implies roughly a 44% probability the BOJ will raise rates by September.
Some traders warn: if the BOJ's tightening pace falls behind inflation, the yen could weaken again, and this intervention's gains would be erased by the market.
What is the biggest lasting fallout for Europe?
Several senior ECB officials have characterized the operation as an "unprecedented breach" of Western monetary-cooperation norms.
One person close to European policy circles called it "deeply shocking" and "hurtful," adding that decades of close cooperation to promote financial stability may now be in jeopardy.
This reflects a deeper question: has the euro become a potential tool in Washington's FX-intervention playbook? If so, European monetary authorities will have to price in an entirely new variable when setting policy.
Content is for reference only, not financial advice.