The USD/JPY approached 164 in July, nearing a 40-year low, prompting Japanese Finance Minister Kaori Hayama to warn that "bold" action would be taken if necessary to address disorderly volatility.
For traders, the 163 to 165 range is not just an exchange rate range but a policy test zone. Will Japan directly intervene to buy the yen? Will the Bank of Japan hike rates sooner? Will carry trades borrowing yen to buy global assets be suddenly disrupted?
This market movement is also prone to misinterpretation. A more assertive stance by the Ministry of Finance does not equate to actual market intervention. Discussions about pension funds rebalancing do not mean that the "national team" buying yen has already occurred. The market is trading on the transition of Japan's policy toolkit from verbal warnings to expanding rate hike expectations and quasi-rebalancing buying.
Yen Weakness has Transmitted to Import Inflation
The trouble with this yen depreciation is that it is not confined to just the USD/JPY pair. The trade-weighted exchange rate is also at a low, indicating that the yen is not only weak against a strong dollar but is also weak against a basket of major trading partner currencies.
The trade-weighted exchange rate can be understood as a "yen composite thermometer." If it were just the strong dollar, the yen would not necessarily depreciate against other currencies. If the trade-weighted index is declining, imports, inflation, and residents' purchasing power will all come under pressure.
The oil price exacerbates the issue. Brent crude oil has recently surged due to Middle East tensions, approaching $100, and Japan is a major energy importer. Rising oil prices combined with yen depreciation will make imported energy, food, and raw materials more expensive.
This is also why the Bank of Japan cannot simply treat the exchange rate as a foreign exchange market issue. The weaker the yen gets, the higher the import costs, making inflation stickier. The market is betting that a rate hike may still occur this year, not because the Japanese economy is suddenly overheating, but because exchange rates and oil prices are changing inflation risks.
Ministry of Finance Raises Short Selling Costs First
Shiomi Kozuki's strong stance first changed the risk-reward ratio of the trade, rather than immediately changing the yen's fundamental outlook.
The Japanese Ministry of Finance can use verbal intervention to signal to the market to continue shorting the yen, potentially facing a policy shock at any time. Especially when she mentioned a common framework with the US to take action against disorderly movements, the signal is no longer just "we are watching," but "we reserve the right to act."
The threshold for direct forex intervention is not low. Buying yen and selling dollars would deplete foreign exchange reserves. If oil prices, interest rate differentials, and dollar hedging demand remain unchanged, intervention is more likely to dampen short-term volatility rather than reverse the trend.
The most recent verifiable monthly data from the Japanese Ministry of Finance is up to June 26, 2026. From April 28 to May 27, Japan confirmed intervention of ¥11.7349 trillion. From May 28 to June 26, it was 0. Whether they entered the market in July will depend on subsequent monthly data confirmation.
For retail investors, the risk is not in an immediate trend reversal once the news is out, but in holding the same short yen positions, needing to pay a higher policy surprise premium. Around 163 to 165, shorts can continue to trade on interest rate differentials, but the margin of error is decreasing.
Rate Hikes and GPIF Provide Slower Support
Compared to direct intervention, rate hikes by the Bank of Japan and GPIF rebalancing are more like slow variables, but their impact on pricing may be more lasting.
Bank of Japan officials have recently maintained an open attitude towards earlier-than-expected rate hikes, and market surveys also indicate expectations for further rate hikes within the year. This is not a formal commitment, but it is enough to make traders reassess the yen-dollar spread.
The logic behind yen carry trades is simple: borrow low-interest yen, buy high-interest dollar assets or risk assets. As long as Japanese interest rates remain low and the yen slowly depreciates, this trade is comfortable. If the Bank of Japan's rate hike expectations are brought forward, or the yen suddenly rebounds, the cost of borrowing yen and exchange rate losses will rise simultaneously.
GPIF is the Japanese government's pension investment fund. The Japanese government has recently encouraged GPIF and other pension funds to increase domestic investments, and this news has previously driven the yen and Japanese bonds higher.
GPIF has assets of around ¥293 trillion to ¥294 trillion, with foreign assets of around $931 billion. If some funds are repatriated from overseas bonds or assets to buy Japanese government bonds or yen assets, it will provide marginal support.
Let's be clear about the boundaries here. Rebalancing is more like asset allocation adjustment, not traditional forex intervention. According to media reports citing Goldman Sachs estimates, the potential scale could reach hundreds of billions to around $80 billion. It can ease yen shorts but should not be mistaken for a completed policy bid.
On July 22, the results of Japan's 40-year government bond auction also showed that despite the rise in long-term yields, demand remained strong, alleviating concerns about a "certain rate hike crashing JGBs." This has strengthened another view: Japan's policy mix is more likely to gradually increase the cost of shorting the yen, rather than abruptly shift the exchange rate direction.
Carry Trade Fears Rapid Surge in Volatility
The current key concern is not an imminent collapse of global carry trades, but a sudden surge in volatility.
Carry trades are most afraid of a rapid yen appreciation in a short period. If the exchange rate moves too quickly in the opposite direction, positions borrowing yen to buy assets may be forced to unwind. The trading chain reaction would lead to buying back yen, selling off risk assets, and transmitting forex volatility to US stocks, credit bonds, and high-yield assets.
However, there is not enough evidence at present to support the notion that a "full-scale unwinding has begun." A more accurate statement is that yen shorts still exist, but the safety cushion has thinned. Factors such as oil prices, policy statements, central bank meetings, and intervention expectations are all squeezing the margin of error for this trade.
163 to 165 Emerging as a Policy Test Zone
Key validation points will focus on several areas: whether the Japanese Ministry of Finance's monthly data shows signs of actual intervention in July, whether the Bank of Japan meeting releases a stronger rate hike signal, whether oil prices can maintain their highs, and whether the GPIF shows visible asset allocation actions.
If these variables all point towards policy tightening simultaneously, the range of 163 to 165 will become the trigger zone for the repricing of carry trades. Yen shorts will face higher volatility, more expensive hedging costs, and a more challenging judgment on policy timing.
Conversely, if oil prices fall, the central bank exercises restraint, intervention data is absent, the yen's weakness could persist. However, each approach to a new low is now more likely to trigger a risk premium on policy than before. For cross-asset investors, the yen is becoming part of the global risk asset leverage cost.
Welcome to join the official BlockBeats community:
Telegram Subscription Group: https://t.me/theblockbeats
Telegram Discussion Group: https://t.me/BlockBeats_App
Official Twitter Account: https://twitter.com/BlockBeatsAsia
