US-Japan Yen Intervention Resets Carry Trade Risk After 40-Year Low

The US Treasury and Japan's finance ministry bought yen jointly Friday for the first time since 2011, lifting the currency from a 40-year low above 163 per dollar to near 156.5.

"The coordinated operation has profoundly upped the ante on deterrence — for speculative JPY bears and JPY-funded carry trades alike," said Vishnu Varathan, Mizuho's Asia-Pacific head of macro strategy.

Japanese Finance Minister Satsuki Katayama confirmed the operation Monday, warning the two governments "will not hesitate to conduct further joint intervention." US Treasury Secretary Scott Bessent echoed the stance, saying Washington "will not hesitate to participate in further joint intervention." Bank of Japan data suggested Tokyo may have sold as much as $58.97 billion to buy yen in New York markets Thursday, before the confirmed Friday action. The dollar fell 0.6 percent against the yen to an intraday low of 156.50 in Asian morning trading Monday, while Japan's Nikkei 225 dropped as much as 2.5 percent as the stronger currency weighed on exporter shares.

The intervention targets a yen crushed by the widest rate gap with the US in decades. The BOJ's policy rate stands at 1 percent after a June hike to a 31-year high, while the Fed's benchmark remains well above. Bank of America expects the BOJ to raise rates again in October, with growing risk of a September move. A sustained break below 155 yen could prompt investors to rethink long-held bets on a weaker yen, BofA strategists said.

The joint action marks a departure from decades of US hands-off currency policy. President Trump confirmed Sunday that the Treasury Department assisted its Japanese counterparts, saying the US was "always there for Japan" as a sign of friendship and to help the world economy. The Financial Times, citing sources, reported the US sold euros to buy yen, a tactic that diversifies the intervention's footprint beyond dollar sales.

The last coordinated intervention came in 2011, when the Group of Seven acted to weaken the yen after a devastating earthquake in eastern Japan. This time, the direction is reversed — both governments are buying yen to arrest its slide, which has pushed up import costs and stoked inflation in Japan, hitting household budgets and Prime Minister Sanae Takaichi's approval ratings.

Carry Trade Deterrence, Not Just Currency Support

The intervention's primary target is the yen-funded carry trade, where investors borrow cheaply in Japan to buy higher-yielding assets overseas. US interest rates remain well above Japan's, keeping the trade profitable on paper. But the coordinated action has changed the risk calculus.

Unlike the summer of 2024, when a BOJ intervention, a surprise rate hike, and expectations for lower US rates combined to drive a sharp yen rally, this intervention has not been accompanied by a major shift in rate expectations. The carry trade therefore still makes sense, leaving investors to watch whether the BOJ follows through with more hikes.

Rate Path Holds the Key to a Durable Yen Rally

Analysts caution that intervention alone rarely produces lasting currency moves. "The fundamentals driving yen weakness haven't changed, so we likely won't see one-sided yen rises from this intervention," said Tsuyoshi Ueno, a senior economist at NLI Research Institute.

Michael Wan, a senior currency analyst at MUFG, wrote that while the joint intervention is "historic and significant" and could clear out yen shorts in the short term, "the fundamentals likely still need to change for a more durable move lower in USD/JPY."

Bessent also said the US would consider increasing the size of the Federal Reserve's repurchase facility providing temporary dollar liquidity, calling the tool an "important backstop." The facility, introduced in 2020 during the pandemic, allows Japan to raise dollar liquidity without outright sales of US Treasuries, potentially easing funding pressures on Tokyo for future interventions.

The BOJ's next policy meeting is scheduled for September, with markets watching for a potential rate hike that would narrow the rate differential with the US and reduce the appeal of borrowing yen. If the BOJ holds, the yen could resume its slide, testing the resolve of both governments to intervene again.

This article is for informational purposes only and does not constitute investment advice.