Why Asian Stock Markets Crashed in August 2024

In the first week of August 2024, stock markets across Asia went through their worst stretch in years. Japan's main stock index, the Nikkei 225, fell 5.81% in a single day on August 2 — the worst day it had seen since the early days of the COVID-19 pandemic in March 2020, according to CNBC. An even broader Japanese index, the Topix, dropped 6.14% that same day — its steepest fall in eight years.

The pain spread quickly across the region. South Korea's main index fell 3.65%. Australia's market dropped 2.11%. By August 5, Japan's Nikkei had wiped out all the gains it had made since the beginning of the year, erasing months of strong performance in just days, per Fortune.

When stock markets in three different countries all crash at nearly the same time, the cause is usually something bigger than problems in any one country.

The Yen Carry Trade: How Borrowed Money Set the Trap

To understand what happened, you need to know about something called the "yen carry trade."

Here's how it worked: For many years, Japanese interest rates were near zero — essentially free money. So banks and investment firms borrowed huge amounts of yen at those near-zero rates. They then took that cheap borrowed money and invested it elsewhere — in American stocks, emerging markets, even Japanese stocks themselves — places where they could earn higher returns. As long as the yen stayed weak and Japanese interest rates stayed near zero, the strategy made money.

But in March 2024, Japan's central bank raised interest rates for the first time in 17 years. The increase was small by global standards, but it changed everything. Higher Japanese rates made borrowing in yen more expensive. More importantly, it started to make the yen stronger — and a stronger yen was a problem for anyone who had borrowed yen and invested the money elsewhere.

When the yen got stronger, traders who had borrowed in yen faced a choice: they had to buy back yen to pay off their loans — which meant selling all the stocks and other investments they had bought with that borrowed money. Suddenly, investors everywhere were forced to sell at the same time, creating a chain reaction.

This kind of unwind has happened before. In 1998, a similar situation touched off financial chaos around the world. The mechanics in August 2024 were strikingly similar: a policy shift that compressed profits, cascading forced sales, and the damage flowing outward from Japan to every market connected to the carry trade.

The Middle East Conflict Made It Worse

The August crash did not happen in isolation. At the same time the carry trade was unwinding, Asian markets were also reacting to escalating conflict in the Middle East. Japan's Nikkei fell an additional 3.4% following attacks in the region, while South Korea's main index dropped 2.7%, per The Wall Street Journal.

Japan and South Korea import large amounts of oil. When Middle East conflict spreads, oil prices typically rise — and that directly hits their import costs and the health of their economies. Stock markets price in that risk quickly, sometimes brutally.

The combination of a domestic shock (the Bank of Japan's rate hike unwinding carry trades) and an external shock (Middle East conflict) happening at the same time created a much sharper decline than either problem alone would have caused.

What the Market Losses Tell Us

The speed and breadth of the August selloff reveal something about how Asian stock markets actually work. Foreign investors — many of them borrowing in yen through carry trade positions — held a large and growing share of Japanese stocks during the rally earlier in 2024. When the exit happened, it was not orderly or measured. Markets that had absorbed big bets from carry traders lacked enough natural buyers willing to step in quickly and catch the falling prices.

A separate hit came when U.S. technology stocks fell in late July 2024. Asian semiconductor companies — chip makers in Japan, South Korea, and Taiwan — had rallied on expectations of strong demand tied to the AI boom. When U.S. tech stumbled, those expectations repriced fast, and semiconductor stocks across Asia fell sharply. This matters because chip-related companies carry heavy weight in Asian stock indexes.

What Happens Next

The Bank of Japan signaled its rate decision coming in March 2024, so it was not a surprise. But the speed and violence of the carry trade unwind suggests the market had underestimated how much borrowed yen was actually sitting in positions around the world. This is a pattern financial history repeats: a profitable strategy runs smoothly until the moment it doesn't, and when it breaks, the unwinding is rarely gradual.

Several questions now hang over the markets. How much of the carry trade still sits in yen-funded positions? How much higher does the yen need to climb before another wave of forced selling begins? And have Japanese corporate profits — which drove much of the stock rally — been repriced to account for a new environment of higher interest rates?

The August crash wiped out months of gains in just days. By itself, it does not suggest that Japan's stock market recovery is fundamentally broken. That recovery had real foundations: improvements in how companies are run, better returns to shareholders, and stronger earnings. But August 2024 was a sharp reminder that when the funding of a stock rally depends on cheap borrowed money, the rally itself carries that borrowed money's risk. When that risk unwinds, so does the rally.

By the time Asian markets reopened, the calendar had moved forward. The underlying positions and the questions they raised had not.