According to ctee.com.tw and Liberty Times Net (ltn.com.tw), Japan's Finance Minister Katayama Satsuki confirmed on August 3 that Japan and the US Treasury coordinated yen purchases on July 31 — the first joint Japan-US currency intervention since 2011 — after the yen neared a 40-year low; USD/JPY traded at 155.61 by 8:50am Taipei time, up 1.23%.
How Japan and the US Confirmed the Joint Intervention
According to ctee.com.tw, Japan's Finance Minister Katayama Satsuki was set to announce that Japan and the United States had taken joint action in the foreign exchange market to stop the yen from sliding to a 40-year low. The confirmation followed days of ambiguity: on July 31, when reporters at the Ministry of Finance asked Katayama directly whether the yen's sudden rally was linked to intervention, she declined to confirm it, saying only, "I cannot answer on that point," while adding, "We are always on high alert and taking response measures."
That ambiguity ended on Monday, August 3. Per ltn.com.tw, Katayama's statement that day confirmed that at US Eastern time on July 31, Japan and the US Treasury had coordinated to buy yen and intervene in the currency market. Separately, ltn.com.tw reported that President Trump, questioned aboard Air Force One on Sunday, August 2, had already confirmed the US had stepped in to help support the yen — calling the move a "signal of friendship" between Japan and the US that would also benefit the global economy.
Why the Yen Was Considered Severely Undervalued — and Why This Marks the First Joint Intervention Since 2011
ctee.com.tw reported the coordinated action would be the first joint Japan-US currency intervention since 2011, aimed at lifting the yen off its weakest level against the dollar since 1986. The rationale traced back to US Treasury Secretary Scott Bessent, who said the previous week that the yen "appears to me to be severely undervalued." A Reuters photograph cited by ctee.com.tw showed a notebook Bessent carried into a Friday cabinet meeting with a "To Do" list that included "Buy Yen $5–10 billion."
Separately, ltn.com.tw described the joint action as extremely rare, noting it was the first such coordinated intervention in 15 years — since the 2011 Great East Japan Earthquake. The two outlets' figures — "first since 2011" (ctee.com.tw) and "first in 15 years since the 2011 earthquake" (ltn.com.tw) — describe the same gap from two angles, reinforcing how unusual the move was.
Japan's Specific Scale and Actions in the Yen Intervention
Japan moved before the joint confirmation was public. Per ctee.com.tw, a market source told Reuters that Japan's government carried out a "buy yen, sell dollar" intervention during New York trading hours on Thursday, July 30.
ltn.com.tw added scale to that action: Bank of Japan data indicated Japan may have sold as much as $58.97 billion (roughly NT$1.9 trillion) in dollar holdings in the New York market that same day, July 30, to support the currency, and that Japan re-entered the market again on Friday.
US Intervention Plans, Fund Scale, and Policy Resolve
On the US side, Bessent's notebook — reported by ctee.com.tw — pointed to a planned scale of $5 billion to $10 billion in yen purchases. ctee.com.tw also reported that the US Treasury notified multiple banks on Friday that Washington might intervene in the yen market and instructed them to "be ready for future action."
That resolve was reiterated once the intervention was confirmed. Per ltn.com.tw, Bessent posted on X that "economic security is national security," and that the US-Japan alliance is built on both. He said the Treasury would keep in close contact with Japan's Ministry of Finance and the Bank of Japan, and would "not hesitate" to join further coordinated intervention.
Short-Term Market Reaction and Future Coordination Commitments
The immediate market move was measurable: ltn.com.tw reported that at 8:50am Taipei time on August 3, USD/JPY traded at 155.61, with the yen up 1.23%.
Both sides signaled the action was not necessarily one-off. Per ltn.com.tw, Katayama said Japan and the US had begun addressing the yen's "excessive volatility and disorderly moves," and that the two countries would "not hesitate" to carry out further coordinated intervention — language that echoed Bessent's own "not hesitate" pledge on X the same day.
Key Figures at a Glance
| Date | Actor | Figure | Source |
|---|
| Jul 30, 2026 | Japan (BOJ data) | Up to $58.97B in dollar sales, New York market | ltn.com.tw |
| Late Jul 2026 | Bessent's notebook | "$5–10 billion" yen-buying to-do note | ctee.com.tw |
| Jul 31, 2026 (US ET) | Japan MOF + US Treasury | Coordinated yen purchase confirmed | ltn.com.tw |
| Aug 3, 2026, 8:50am Taipei | USD/JPY | 155.61, yen up 1.23% | ltn.com.tw |
| — | Yen vs. USD | Approached 40-year low; weakest since 1986 | ctee.com.tw |
| 2011 → 2026 | Japan-US joint intervention | First in 15 years (since 2011 earthquake) | ltn.com.tw / ctee.com.tw |
What This Means
The timeline the two outlets lay out shows a gap between unilateral and joint action: Japan alone sold up to $58.97 billion in New York on July 30, a day before the US Treasury's coordinated purchase on July 31 was confirmed — suggesting Tokyo acted first and Washington joined a day later. The scale gap is also notable: Bessent's own "to do" figure of $5–10 billion in planned yen purchases is a fraction of the $58.97 billion Japan is reported to have already committed, indicating the US contribution was intended as a signaling complement rather than a matching sum. Finally, the near-identical "will not hesitate" language used separately by Katayama and Bessent — paired with the 1.23% yen move to 155.61 recorded on August 3 — points to a deliberate, coordinated messaging effort alongside the currency action itself, following an intervention gap of 15 years since the 2011 Great East Japan Earthquake.