Why Asian Stock Markets Crashed in August 2024

In the first week of August 2024, stock markets across Asia experienced a sharp, widespread sell-off. Japan's Nikkei 225 index fell 5.81% on August 2 alone — its worst single day since the COVID-19 pandemic shock of March 2020 — breaking below the 36,000 level for the first time since January, according to CNBC. Japan's broader Topix index fared worse, dropping 6.14% — its largest single-day loss in eight years.

By August 5, the damage had spread further. The Nikkei had wiped out all of its gains for the entire year, reversing months of strong rally that had made Tokyo one of the most watched stock markets globally, per Fortune.

The Damage Spread Across the Region

The losses were not limited to Japan. South Korea's Kospi index fell 3.65% on August 2 to close at 2,676.19 — its worst day since August 2020 — while the tech-heavy Kosdaq dropped 4.20%, touching its lowest level since November 2023. Australia's S&P/ASX 200 fell 2.11% to 7,943.2, marking its sharpest one-day drop since March 2023. Technology and semiconductor stocks were hit especially hard on August 5, following weakness in U.S. tech stocks the prior week — a connection that shows how quickly market moves now travel around the world.

When stock markets in Sydney, Seoul, and Tokyo all decline sharply on the same day, the cause is usually not specific to one country. Something bigger was moving the entire region.

Understanding the Yen Carry Trade

To explain what happened, we need to understand a trading strategy called the yen carry trade. For many years, large institutional investors borrowed money cheaply in Japanese yen — at interest rates near zero — and used that borrowed money to buy higher-returning investments elsewhere: U.S. stocks, emerging market bonds, even Japanese stocks. This strategy worked as long as the yen stayed weak and Japanese interest rates remained near zero.

This changed in March 2024, when the Bank of Japan raised interest rates for the first time in 17 years. The rate increase was small by global standards, but it had large consequences. When Japanese interest rates began to rise, even gradually, three things happened at once. First, the cost of borrowing yen went up, making the carry trade less profitable. Second, a higher rate environment typically strengthens a currency — in this case, making the yen more valuable. Third, and most painful: when the yen strengthens, investors who borrowed in yen are forced to close out their trades, buying back the yen they owe and selling the assets they had bought with it.

This is a well-known pattern in financial markets. The most famous example happened in 1998, when a crisis in Russia and the collapse of a major investment fund (LTCM) triggered a rapid yen appreciation and market shock that spread globally. The mechanics in August 2024 were remarkably similar: a policy change made the trade more expensive, leading to cascading financial pressure on traders, forced selling of assets, and losses cascading through every market and asset class touched by the carry trade.

A Second Shock: Geopolitical Risk

The August sell-off did not happen in isolation. Beyond the yen carry trade unwind, Asian markets were also reacting to escalating conflict in the Middle East. The Nikkei fell an additional 3.4% following attacks in the region during 2024, while South Korea's Kospi declined 2.7% in the same episode, per The Wall Street Journal.

Japan and South Korea are among the world's largest importers of crude oil. Any widening of conflict in the Middle East directly threatens their energy supplies and increases their import costs — a risk that equity markets price in quickly and sometimes harshly.

The timing here mattered. A domestic financial shock (rising Japanese rates) hit just as an external geopolitical shock (Middle East tensions) was developing. The combination amplified the speed and scale of the sell-off far beyond what either factor alone would have caused.

What This Reveals About Today's Markets

The speed and scope of the August declines tell us something about how modern Asian equity markets are structured. Foreign institutional investors had purchased a large share of Japanese stocks during the pre-crash rally — many of them using borrowed yen to finance these purchases. When those investors needed to exit, the process was not orderly. The Topix's 6.14% single-day drop and the Kosdaq's drop to a nine-month low suggest that markets had absorbed large directional bets with few natural buyers stepping in to absorb the selling.

On August 5, semiconductor and chipmaker stocks sold off sharply. Asian semiconductor companies had surged on expectations that artificial intelligence demand would drive growth. When U.S. technology stocks weakened in late July 2024, those AI-fueled expectations were quickly repriced. Since Seoul, Tokyo, and Taipei all have major semiconductor industries, the selling was concentrated and severe.

The broader context here is that Asia's markets had grown increasingly dependent on capital flows from yen-funded carry trades and momentum from U.S. technology gains. When both sources of support reversed, there was little to prevent a sharp drop.

Looking Back and Looking Forward

The Bank of Japan's March 2024 rate decision was announced ahead of time and widely expected. What surprised markets was how fast and far the repricing went once the yen carry trade began to unwind. This suggests that the amount of leverage built up in yen-funded positions was substantially larger than investors and analysts had estimated — a pattern we see repeatedly in financial history. A profitable trade works smoothly right up until it doesn't, and the unwinding is rarely gradual.

Several important questions remain. How much exposure to yen carry trades still exists in global markets? At what point would further yen strength trigger another round of forced selling? And have Japanese company earnings — which had driven much of the Nikkei's record rally earlier in 2024 — already adjusted to reflect a new, if still modest, rate environment?

The August sell-off erased months of gains in a matter of days. On its own, this episode did not indicate that Japan's broader stock market recovery is broken. That recovery had been built on real improvements in how Japanese companies are managed, how they return profits to shareholders, and the quality of their earnings. But August was a sharp reminder that when a market rally is partly financed by cheap borrowed money, the health of the rally and the stability of that funding are connected. When the funding unwinds, the rally unwinds with it.

The calendar moved forward. The underlying questions, and the risks they posed, did not.