The market is pricing in an 84% probability of a rate hike by the Bank of Japan in September — what is happening with the yen
This shift in sentiment came after the currency intervention by Japanese authorities stopped supporting the yen. The national currency has given back a significant portion of its recent gains and is posting its worst weekly performance in three months.
The Effect of Intervention Is Fading
This week, the yen has fallen by about 1%—to 159.43 yen per dollar. This is the worst weekly result since May. Notably, the currency has already given back about half of the gains achieved after the coordinated currency intervention by the Bank of Japan in late July and early August. Before these measures, the exchange rate was holding around 164 yen per dollar.
Similar dynamics have been observed before. After the April intervention, the yen returned to 40-year lows in the following months, indicating the limited effectiveness of one-off measures without a change in fundamental policy.
Tokyo's former top currency diplomat Mitsuhiro Furusawa notes that authorities could deploy currency reserves again at any moment. According to him, officials are also ready to signal to the market a faster pace of rate hikes to support the national currency.
Traders Bet on a Rate Hike
The link between intervention and key rate decisions explains the shift in market expectations. Polymarket participants now estimate the probability of a quarter-point rate hike at more than 80%. OCBC strategist Sim Moh Siong believes that interventions alone will not reverse the dynamics of the Japanese currency.
"It's no surprise that the yen has given up ground again," the analyst notes.
In his assessment, the yen needs clear support from the Bank of Japan, which is ready to tighten monetary policy. This view aligns with growing expectations of a faster rate hike, as inflation approaches the target level.
The opposite scenario carries risks: if the regulator leaves the rate unchanged, the market will quickly react with disappointment. After such decisions, the yen has already fallen to 160 per dollar. Currently, market participants are counting on central bank moves rather than new currency interventions.
My comment: The sharp jump in probability on Polymarket reflects not only the technical dynamics of the yen but also a paradigm shift: the market no longer believes in targeted interventions as a sustainable tool. However, 84% is still not a consensus, and any dovish signal from the Bank of Japan could trigger volatility both in fiat pairs and in cryptocurrencies sensitive to global liquidity.