The United States sold euros to buy yen last week, Stelleblinded the European Central Bank after the operation was executed.

ECB President Christine Lagarde and Treasury Secretary Scott Bessent spoke about the intervention only after it had been carried out, a move that highlighted the unusual nature of the first joint Washington‑Tokyo effort in almost 30 years. The US, acting through the New York Federal Reserve on behalf of the Treasury, opted to use euros rather than dollars, a decision that many senior ECB officials described as an unprecedented breach of long‑standing conventions of co‑operation.

The intervention pushed the yen sharply higher from almost ¥164 to the dollar, its lowest level since 1986, before weakening to ¥158. Analysts note that the Bank of Japan may have spent ¥13.8 tn in two days, a figure that eclipses its previous record campaign. Traders now assign a 44 % chance that the BoJ will raise rates at its next meeting.

The move also raises concerns that the Bank of Japan is not acting quickly enough to contain rising inflation, even as US borrowing costs hover near 19‑year highs.