It looks like a distant currency problem. It is in fact the mechanism funding an enormous share of positions in tech stocks, bonds and crypto.
Published on July 22, 2026 · by Alex · Japan · Currencies · Carry trade
While attention sits on artificial intelligence, one chart has set off alarms again: the dollar has passed 162 yen.
That number could become one of the most important of the coming weeks, and the reason has less to do with Japan than with how half the market is funded.
Japan has spent months trying to slow its currency's decline. The sequence is always the same: first speeches, then warnings, and when words stop working only expensive decisions are left.
The best known is direct intervention: selling dollars and buying yen to hold the currency up. The problem is that this only buys time, because the cause is elsewhere. As long as the United States keeps rates far above Japan's, money will keep leaving the yen in search of better returns.
The 160 yen per dollar level is treated as a critical threshold, marking territory not seen since the 1980s.
Here is the mechanism connecting Tokyo to a tech stock in New York.
For years, borrowing in yen was close to free. Many investors did the obvious thing: take cheap yen debt and buy higher-yielding assets in other currencies — stocks, bonds, crypto, emerging markets. That is the carry trade.
It works while the yen is weak or stable. If the yen strengthens abruptly, the debt to be repaid gets more expensive in real terms, and whoever took it needs yen fast to close the position.
Where does that yen come from? From selling what was bought. Which is why a Japanese intervention does not stay in the currency market: the dollar-yen pair becomes a simultaneous sell order across half the world.
And there is what few observe: the longer Japan waits, the bigger the move can be when it finally acts.
The market is no longer waiting for a statement from the Bank of Japan: it is waiting for an action. And the more positioning accumulates on the short-yen side, the more people have to leave through the same door when that action arrives.
There is one more data point worth keeping on the radar: the Bank of Japan has begun selling US Treasury bonds.
It is coherent — selling those bonds generates dollars that can be used to buy yen — but it has a side effect: it pushes US yields up exactly when the debt market is already strained. A Japanese currency policy decision ends up making mortgages more expensive in the United States.
The question is no longer whether Japan will intervene again. It is how much longer it can avoid a decision that would shake rather more than Tokyo.
Borrowing in yen, which for years was nearly free, and using that money to buy higher-yielding assets in other currencies: stocks, bonds, crypto, emerging markets. It works while the yen stays weak or stable. If the yen strengthens suddenly, repaying that debt gets more expensive in real terms.
Because anyone who borrowed in yen needs yen fast to close the position if the currency strengthens, and those yen come from selling whatever they bought. That is why a Japanese intervention does not stay in the currency market: it turns into a simultaneous sell order across half the world.
Around 160 yen to the dollar, territory not seen since the 1980s; the pair has already passed 162. And there is a paradox: the longer Japan waits to intervene, the bigger the move can be when it finally does, because more positions have to leave through the same door.
This article is the written version of the Saturday analysis.
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