COMMENTARY: Trump frets over the yen, and behind the yen sit $1,104 billion in Treasuries

The question left unanswered

Friday, late morning, Tokyo

Satsuki Katayama refused to say one thing.

On September 25, 2026, at her regular press conference, Japan’s finance minister makes a disclosure. At the summit in New York, Donald Trump said he was worried about the weak yen.

She is asked whether the global rise in bond yields came up as well. She declines to comment, Reuters reports.

The yen, yes. Bonds, not a word.

A minister. A lectern. The rustle of notebooks. A question left hanging.

What the day’s number measures

That morning, it takes about 158 yen to buy a dollar. That is the number all of Tokyo is watching. The one on the currency screens. The one importers watch. The one for households filling the tank.

While the Iran war drives up the cost of the energy Japan imports, every yen lost gets paid for at the pump.

But the unanswered question is not about 158. It is about…

A minister’s silence sometimes says more than her sentence.

A summit confidence

New York, Tuesday the 22nd

Sanae Takaichi met Trump in New York on Tuesday, September 22, on the sidelines of the UN General Assembly.

According to Katayama, Trump voiced concern there about the weak yen. The prime minister replied that, as a general rule, an undervalued yen is a problem.

Later on the 25th, according to Jiji Press, Takaichi fills in Trump’s remark. American trade had suffered from the yen’s depreciation.

She adds that monetary and fiscal matters did not come up.

Cleared by the prime minister’s office

One sentence from Trump. One answer from Takaichi. Reported three days later by a third person.

This kind of exchange normally stays between two leaders. Reuters calls the account unusually candid. The Mainichi calls it exceptional.

Katayama says she is making it public for the first time. She first checked with the prime minister’s office.

So nothing slipped out by accident. The sentence was weighed. Cleared. Delivered on a Friday morning.

An authorized confidence is no longer a confidence. It is a tool.

158.60, then 158

Half a yen

The effect is immediate, and small.

After Katayama’s remarks, the yen moves from 158.60 to about 158 per dollar, according to Reuters.

Half a yen.

On the trading floors, the phones ring.

A few hours earlier, a little after 12:30 a.m. on the 25th, Tokyo time, the dollar had touched 159 yen, TV Asahi reports. Some market players see a chance to cool speculative selling.

The rate check

That same Friday, Japanese authorities run rate checks with the banks. According to Reuters, that is often the prelude to intervention.

In other words: Tokyo takes the market’s temperature before it takes out the money.

This commentary reads Katayama’s confidence this way. It has a currency function. It has a second one, which nobody puts on display.

The yen worries Tokyo. The bonds worry Washington.

Half a yen won, and a question still open.

The road to 159

163 in July

The 158 of September 25 has a history.

In late July, according to the Mainichi, the dollar topped 163 yen. The weakest yen in nearly 39 years.

In early September, after Scott Bessent spoke out against speculators, the yen rebounds fast. On the 8th, it is back below 153.

September 18, a hike that falls short

On September 18, the Bank of Japan raises its rate, Jiji reports. And still the yen slides quickly from 156.

That same evening, the central bank sounds out banks on market levels. The move continues. On the 24th, the dollar crosses 159 yen again.

Rising long-term U.S. rates widen the gap with Japan, the Mainichi writes. The yen sellers come back.

152. 156. 159.

Three numbers in under three weeks.

The yen climbs on a word. It falls back on a spread.

July 31, together

The first time since 1998

On July 31, Tokyo and Washington buy yen together.

It is the first U.S. intervention to support the yen since 1998, the Japan Times notes.

Japan announced it had spent a record $96.4 billion in one month defending its currency.

The Peterson Institute, for its part, put Japanese yen purchases at $87 billion over the last two days of July alone.

The yen had lost about 4.6% since Japan’s previous intervention, carried out alone in the spring, according to the same institute.

The yen had hit, according to Reuters, its lowest in 40 years, near 164. Right after the intervention, it climbed back to 155.20.

Bessent had a line for it back then, cited by the Peterson Institute. The Trump administration keeps its word to America’s trusted partners.

What the summit confirmed

On September 25, Katayama says the New York exchange reaffirmed the shared position behind that intervention. Push back on excessive volatility. Push back on disorderly moves in the yen.

According to Jiji, the two finance ministers say they are ready for another joint intervention.

Katayama adds that she and Bessent will keep in close contact, including on currency.

That is the good move. Trump stands behind a treaty ally, in public, on its currency.

Two capitals buy the same yen. Not for the same reasons.

3.115%

Japanese yields at the top

That same Friday, the yield on Japan’s 10-year bond climbs to 3.115%. Its highest in 30 years, according to Reuters.

Thirty years. Japan had not paid this much to borrow for 10 years since the mid-1990s.

It rises after a heavy selloff in the U.S. market.

The move travels. What sells in New York sells in Tokyo. What sells in Tokyo can come back to New York.

The end of a doctrine

The same day, at another press conference, Economic Revitalization Minister Minoru Kiuchi takes the floor. An ally of Takaichi’s reflationist camp, he declares the era of Abenomics-style stimulus over.

Reuters reads it as a reply to Bessent. The Treasury secretary recently suggested that Japan’s priority should be fighting inflation, not stimulus.

An American minister suggests which doctrine to drop. A Japanese minister drops it out loud.

Japanese yields go up. Japanese doctrine comes down.

The sentence Reuters adds

What worries Washington

The Reuters dispatch of September 25 contains a sentence the official statements leave out.

The weak yen raises the cost of imported energy. That cost is already high because of the U.S.-Israeli war against Iran. It feeds fears of runaway inflation in Japan.

And the United States, the agency writes, fears that a massive selloff of Japanese bonds could spill into the Treasury market.

One sentence. In the middle of a dispatch. And everything else changes meaning.

Its own debt

That is where Katayama’s silence starts to make sense.

If bond yields came up at the summit, nobody says so. If they did not, nobody says that either.

Why refuse to answer a question whose answer would be no?

And yet the fear Reuters attributes to Washington is not about Japanese exporters. It is about Washington’s own debt market.

They talk about the yen so as not to talk about bonds.

The August 27 letter

Bessent writes to Warren

Washington has already put this fear in writing. Once.

In a letter dated August 27 to Democratic Senator Elizabeth Warren, Bessent defends the July intervention. He releases it the next day.

Japan, he writes, is a major holder of U.S. Treasuries. An essential trading partner. A treaty ally.

“Disorderly yen markets can trigger forced unwinds,” he adds. They could destabilize global markets. In the end, they would raise borrowing costs in the United States.

No debt, he says

He releases it on the day the yen weakens past 160 per dollar for the first time since the intervention. According to Reuters, remarks by Federal Reserve Chair Kevin Warsh had just revived expectations of a U.S. rate hike.

Bessent cites a precedent: Argentina, backed last year by the same fund. The best-managed crisis, he writes, is the one that never happens.

Bessent insists. “No credit was extended to Japan.” Japan owes the Treasury nothing.

He does not say how much the Treasury committed. He says only that he swapped foreign-currency assets from his Exchange Stabilization Fund for yen.

The Japan Times notes that Treasury watchers had already tied the intervention to a concern about avoiding higher U.S. yields.

On September 25, the same worry returns. But this time, it is Tokyo carrying it to the microphone, and it is the yen that gets named.

The letter said bonds. The summit says yen.

$1,104 billion

The top foreign creditor

The Treasury Department publishes a monthly list of the major foreign holders of its debt.

In July 2026, Japan holds $1,103.9 billion of it. It is the top foreign holder. In June, the figure was $1,116.7 billion.

$1,104 billion is more than the United Kingdom’s $998.3 billion. $1,104 billion is far more than mainland China’s $618 billion. $1,104 billion is nearly 12% of the $9,248.1 billion held abroad. It is $39.2 billion less than in May. It is one country’s debt held by an ally defending its currency.

Selling to defend

To buy yen, you have to sell something else. Dollars, often. Treasuries, sometimes.

Economist Maurice Obstfeld wrote as much on August 11 for the Peterson Institute. Heavy Treasury sales by a holder as large as Japan could strain the market and push up rates. U.S. participation lets Japan sell less.

He also notes that the Treasury market has grown more fragile as U.S. public debt has swelled.

That is what makes the head spin. Not half a yen. The largest foreign claim on America, in the hands of a country that has to defend its currency.

Minus $39.2 billion in two months.

The table does not say why.

And yet the word contagion appears in none of the public statements reported that Friday.

The yen gets defended with Treasuries.

Tokyo has its own reasons

Tokyo wants a stronger yen too

Here is the strongest objection. It is serious.

It is not Washington pushing its fear onto Tokyo. It is Tokyo that needs a stronger yen.

The energy bill climbs. Inflation looms. The Bank of Japan raises rates. The authorities run rate checks. Takaichi herself calls an undervalued yen a problem.

And Trump, according to Takaichi, was talking about trade. Not bonds.

A weak yen helps Japanese exporters. That is precisely what Trump complained about, according to Takaichi.

The order of fears

True. The interests converge, and the confidence serves the yen first.

And yet convergence does not erase the order of fears. Tokyo fears imported inflation. Washington, according to Reuters, fears contagion into its own bonds.

Both fears fit into the same week. Only one gets spoken into the microphone.

The interests converge. The fears do not sound the same.

The same Washington

The yen buyer and the tariff setter

We have to judge the act. Not the person.

The same Washington buys yen on July 31. The same Washington hits Japan with tariffs, including the most recent ones under Section 301, the Peterson Institute notes. The same Washington extracts $550 billion in investment from Japan for projects the administration chooses.

According to Obstfeld, these measures tend to weaken the yen.

Another detail, tucked into a note by the economist. On July 31, the Treasury sold euros to buy yen, without first consulting eurozone authorities. They were annoyed.

Three moves. One capital.

Defending one ally while ruffling others. The gesture is small. The signal is not.

Tax, then support

He also notes that Takaichi’s fiscal plans, which unsettle markets, are partly driven by defense spending the Trump administration encourages.

That is the bad move. Push an ally to spend. Tax it. Demand billions from it. Then worry about its currency.

And here is the good move, in the same week. Name the problem at the summit. Stand behind the intervention. Keep the ally in the Western camp rather than leave it alone against the markets.

Obstfeld concludes that intervention is no free lunch.

Washington props up the yen it helps weaken.

What the market heard

The afternoon half-yen

In the early afternoon in Tokyo, TV Asahi sees the yen around 158 and a half.

Hirofumi Suzuki, a currency strategist at Sumitomo Mitsui Banking, tells Reuters of heightened concern in Tokyo. Especially after Friday’s rate checks.

In the market, nobody has forgotten July 31. Friday’s rate checks are a reminder. For anyone tempted to forget.

The week ahead

Takaichi also says she had a timely discussion with Trump about China, ahead of his summit with Xi Jinping.

The currency, for its part, will follow U.S. rates. The dollar is rising, according to Reuters, on solid U.S. data, a firmer Federal Reserve and sharply higher yields.

Bessent has also urged the Federal Reserve to expand its repo facility for foreign central banks, according to Obstfeld. A way to spare them from selling Treasuries into a shaky market.

I will admit one thing. I distrust Fridays when a minister talks about currency and goes quiet on debt.

They are often the ones that count.

The market heard the yen. It is waiting for the rest.

Two uses for one sentence

Braking the yen

Here is my verdict. Katayama’s confidence has two functions.

It serves to brake the yen’s fall, by lending Tokyo Trump’s voice. It serves to remind everyone that the ally defending its currency also holds $1,104 billion of American debt. It serves to tell markets that Tokyo and Washington are watching the same screen.

The first function is on display. The second stays silent. The third can be guessed.

A mutual dependence

We can call that diplomacy. We can also call it a mutual dependence nobody wants to name at the microphone.

Japan needs dollars to pay for its energy. America needs Japan to place its debt.

The silence of September 25 protects both.

The yen is the text. The debt is the subtext.

Who protects whom

The evening number

On the evening of September 25, the yen trades around 158. The minister has spoken. Japanese bonds are at their highest in 30 years. Japan still holds $1,104 billion in Treasuries.

Japan still has the same need. Energy paid for in dollars, in a war that drives the price up.

This morning, 158 was an exchange rate. Tonight, it is also Washington’s thermometer.

The creditor and the ally

When an ally holds $1,104 billion of American debt and has to sell to defend its currency, who, exactly, is protecting whom?

Katayama’s next regular press conference may add a word. Or take one away.

Behind the yen, $1,104 billion, and silence on the bonds.

Sources:

Primary Sources:

• Reuters — Katayama, Trump and the weak yen, September 25, 2026
• Jiji Press — Takaichi on her summit exchange with Trump, September 25, 2026
• U.S. Treasury — major foreign holders of Treasury securities, July 2026

Secondary Sources:

• TV Asahi — the yen after Katayama’s remarks, September 25, 2026
• Japan Times — Bessent’s letter on a disorderly yen, August 29, 2026
• Peterson Institute — the U.S. contradictions around the yen, August 11, 2026