US sale of euros to support the yen during the historic joint intervention late last week reportedly blindsided the ECB, with the US only informing Europe after the historic currency intervention took place, according to FT

US sale of euros to support the yen during the historic joint intervention late last week reportedly blindsided the ECB, with the US only informing Europe after the historic currency intervention took place, according to FT.

Coordinated intervention is rare enough that each episode becomes its own precedent; historically, joint operations to support the yen have been conducted with the G7 partners aligned in advance, and the choreography of consultation has mattered almost as much as the size of the flows. A US decision to sell euros rather than dollars in such an operation is the more unusual wrinkle: intervention has conventionally been executed in the dollar leg of the pair, and routing it through EUR/JPY effectively drafts a third central bank's currency into the trade without its consent. The reported failure to notify the ECB beforehand cuts against the established convention that intervention affecting another reserve currency is flagged in advance, and past episodes of friction between major central banks over exchange rate operations have tended to surface later as reluctance to repeat the cooperation. The channels worth watching are whether the ECB responds formally or through commentary, whether follow-up operations revert to the dollar leg, and whether EUR/JPY flows show residual official footprints. Coordination episodes of this kind have historically been effective only when the partners were seen to be acting in concert; visible discord between the actors has tended to shorten the half-life of the signal.