The Japanese yen strengthened significantly on August 3 amid speculation that Japan’s authorities intervened once again to support the currency following coordinated action with the United States last week. The yen surged as much as 1.4 percent against the US dollar during morning trading before settling to a 0.5 percent gain at 156.71 per US dollar by late afternoon Singapore time. It also rose up to 1 percent against the Singapore dollar, reaching 122.24 by the same time, marking a cumulative appreciation of over 3 percent against the Singapore dollar since the intervention at the end of July.

Market analysts and strategists noted that the price movements resembled official intervention. Gareth Berry, a strategist at Macquarie Group, pointed out that Japan's Ministry of Finance appeared to be capitalizing on a narrow window to impact USD/JPY exchange rates and challenge technical support levels. Under International Monetary Fund guidelines, Japan could legally intervene up to three times every six months, each intervention lasting no more than three business days. Having engaged in operations on July 30 and 31, the possibility of a third intervention on August 3 fell within these parameters.

The current intervention is part of an unusually close collaboration between Japan and the US Treasury, a level of cooperation unseen in decades, aimed at reversing the yen’s sharp depreciation. Treasury Secretary Scott Bessent affirmed that the US would not hesitate to intervene again if necessary, while President Donald Trump emphasized the move as “a signal of friendship.” Japan’s Finance Ministry confirmed the joint intervention on August 3 and indicated readiness to take further measures. Data from the Bank of Japan suggested that Japan may have spent approximately US$36.58 billion to purchase yen during recent market operations.

While some market participants remain skeptical about the long-term effectiveness of such interventions in a daily currency market valued at around US$9.5 trillion, the authorities have demonstrated considerable influence over short-term currency movements. In just two days last week, combined market operations, official communications, and public remarks from Bessent and Japan’s Finance Minister Satsuki Katayama successfully reversed more than two months of yen depreciation.

Strategists at Goldman Sachs indicated the likelihood of further interventions if the yen’s gains begin to reverse, asserting that intervention remains a viable tool to buy time until underlying economic fundamentals improve. This joint action marks the first coordinated effort since 2011, when authorities intervened to weaken the yen after a major earthquake in eastern Japan.

The yen’s decline in recent months has been driven by factors including rising oil prices, Japan’s persistent fiscal deficits, and a widening interest rate gap with the US and other major economies. Tokyo’s concern stems from the impact of the yen’s weakness on import costs, which pressures Japanese businesses and consumers. The repercussions extend beyond Japan, as volatility in its financial markets tends to ripple through the global economy.

Masayuki Namayama, senior currency strategist at Mizuho Bank, highlighted that the significance of recent interventions may lie more in the message they send rather than the actual transactions. Rising concerns in Washington over yen depreciation and volatility in the Japanese government bond market, as well as potential spillovers to the US Treasury market, likely influenced the joint actions.

This yen volatility has also caused fluctuations in US Treasury yields, drawing criticism from Bessent earlier this year. The increased competitiveness of Japanese exports due to the weaker yen has added tension to US-Japan trade relations, with Trump acknowledging on Air Force One that the interventions provide “financial benefit” to the US and support the global economy.

Experts like Rebecca Patterson, a senior fellow at the Council on Foreign Relations, noted Japan’s potential sale of US Treasuries to finance these interventions, which could pose risks to Treasury yields if sales escalate. This context underscores Bessent’s interest in dissuading Japan from expanding such sales.

Further underscoring the US commitment, a photograph taken during a late July Cabinet meeting showed a notepad before Bessent listing “Buy Japanese Yen (JPY) $5-10 bil” among his priorities. Bessent had previously described the yen as “yet undervalued” and cautioned against excessive volatility in currency markets.

OCBC strategist Moh Siong Sim said that with joint action ongoing, the USD/JPY exchange rate could dip below 155 if stop-loss orders are triggered. However, he noted that the long-term success of intervention efforts largely depends on whether such efforts are supported by a more hawkish stance from the Bank of Japan.