Why historic intervention hasn't stopped the yen's slide

Photo: Qing Luo · Pexels

Intervening in the currency market is, in essence, a bet that monetary authorities can push a currency's price in a direction opposite to what the market wants to do with it. The United States and Japan tried this jointly, in a move described as historic for its scale and coordination. Yet the yen keeps weakening, raising an uncomfortable question: why hasn't it worked?

The answer has to do with something deeper than a one-off intervention. When there's a sustained interest rate gap between two economies, investors tend to move toward the currency offering higher returns, funding that position by borrowing the cheaper currency. This mechanism, known as the carry trade, generates a constant selling flow on the weak currency that no isolated intervention can counter durably if underlying conditions don't change.

A curious contrast: safe haven in moments of panic

It's interesting to note that, during specific episodes of market nervousness, both the yen and the Swiss franc have acted as safe havens, attracting buyers seeking protection from volatility. This shows that the yen's structural weakness and its role as a safe-haven asset in times of stress aren't contradictory, but two sides of the same coin depending on the time horizon and risk appetite of the moment.

For markets, this episode is a reminder that currency interventions have limited reach when competing against persistent interest rate differentials. Until those underlying conditions shift, pressure on currencies like the yen will likely remain a recurring theme in global macroeconomic conversation.