Bank of America has identified price behavior it believes reflects at least four separate yen-buying interventions by Japan's Ministry of Finance during the Golden Week holiday period. The bank's analysis points to moves on April 30, May 1, May 4, and May 6 that align with official selling of dollars and buying of yen.
According to BofA strategist Shusuke Yamada, the market reaction after the suspected interventions showed consistent lows in the mid-155s and highs contained near the mid-157s. The first of the operations observed in this series appears to have been initiated when USD/JPY was trading in the low-160s.
Yamada notes that earlier intervention episodes in April-May 2024 and July 2024 also started when USD/JPY sat in the high-150s to low-160s, "suggesting that the Japanese government may view levels around USD/JPY 160 as a line in the sand."
The scale of the latest activity is likely large. Bloomberg has estimated that the April 30 operation alone amounted to 5.4 trillion yen, based on Bank of Japan current account data. Applying a rule of thumb from past interventions of about 1 yen of USD/JPY movement per 1 trillion yen deployed, Yamada places a rounded estimate for the full series at approximately 11 trillion yen, or roughly $72 billion. He cautions the figure is highly uncertain, however.
Japan's foreign exchange reserves, at close to $1.4 trillion, mean that funding the operations does not appear to be the immediate constraint. Yamada lays out a scenario in which, if interventions were to stop and cash balances were maintained through maturing securities and investment income, the implied asset sales into markets - generally assumed to be U.S. Treasuries - would be on the order of $40 to $50 billion.
Another constraint cited by Yamada is Japan's classification under the International Monetary Fund as a free-floating currency. That designation allows up to three intervention episodes of as much as three business days each within any six-month window. Recent operations have remained inside that limit, and the price action on May 6 suggested a second distinct episode may already have begun, leaving May 7 and May 8 available for possible additional activity.
The strategist is also monitoring expectations for the Bank of Japan's policy path. He writes that "the momentum toward a BoJ hike at the June meeting is unlikely to fade," and notes that market pricing currently implies around a 70% probability of a June rate move. Yamada adds that if large-scale intervention were to temporarily strengthen the yen and push June-hike pricing down to around 40%, such a move would be viewed as "an opportunity to pay."
Overall, the assessment from BofA frames the recent operations as potentially material in size and influential for both FX dynamics and expectations for Japanese monetary policy. The estimates, including the possible 11 trillion yen cumulative figure and the April 30 single-operation estimate of 5.4 trillion yen, are described as approximate and subject to significant uncertainty.
Key points
- At least four suspected yen-buying interventions occurred on April 30, May 1, May 4, and May 6, with USD/JPY lows in the mid-155s and highs capped in the mid-157s.
- BofA estimates the full sequence could be about 11 trillion yen, roughly $72 billion, using a historical rule of thumb and a Bloomberg estimate that April 30 alone was 5.4 trillion yen.
- Potential impacts include pressure on FX markets and the possibility of asset sales into U.S. Treasuries estimated at about $40 to $50 billion if cash balances are maintained.
Risks and uncertainties
- The scale estimate for the full intervention series is highly uncertain and based on a rough rule of thumb.
- Intervention activity must remain within IMF free-floating limits, which allow a restricted number of multi-day episodes in a six-month window.
- Shifts in market pricing for a Bank of Japan June rate move - currently around a 70% probability - could be affected by intervention, creating uncertainty for interest-rate-sensitive markets.