The market is pricing in an 84% probability of a rate hike by the Bank of Japan in September.
The derivatives market and prediction platforms are showing a sharp shift in expectations regarding the Bank of Japan's (BoJ) monetary policy. Polymarket participants now estimate the probability of a key interest rate hike at the September meeting at 84%. Just two weeks ago, this figure stood at only 22% — such a rapid reversal in sentiment points to profound changes in how the Japanese regulator's actions are perceived.
Failed interventions: the yen under pressure again
The key trigger for revising expectations has been the weakening effect of currency interventions. Despite active measures by authorities, the yen continues to lose ground. This week, the USD/JPY exchange rate rose by approximately 1%, reaching 159.43 — the worst weekly result since May. Notably, the Japanese currency has already given back about half of the gains recorded after the coordinated BoJ intervention in late July — early August, when the rate bounced off the 164-per-dollar level.
The historical context only amplifies concern: after similar interventions in April, the yen slid back to 40-year lows within several months. This suggests that one-off measures without changes to fundamental monetary policy are unable to drastically alter the trend.
The market expects action from the regulator, not one-off injections
The sharp shift in Polymarket estimates reflects a growing understanding: stabilizing the currency requires not targeted interventions, but systemic steps from the BoJ. Inflation in Japan is steadily approaching the target level, giving the regulator formal grounds for policy tightening. Moreover, former top Tokyo currency diplomat Mitsuhiro Furusawa recently emphasized in comments that authorities are ready to deploy currency reserves at any moment, as well as signal the possibility of faster rate hikes.
Market strategists agree that the yen needs clear support from the Bank of Japan, which is willing to tighten policy. Without this, any rebound will be temporary. At the same time, the opposite scenario carries significant risks: if the regulator leaves the rate unchanged, market disappointment could instantly push the yen down to 160 per dollar, as has happened before.
My view: The market has essentially stopped believing in the effectiveness of currency interventions as a standalone tool. Now all attention is focused on rate decisions. The 84% probability looks overstated, but the very fact of such consensus puts pressure on the BoJ, forcing it to act more decisively to avoid losing market trust.