The yen-carry unwind: August 2024's global volatility shock
Backfilled context carries a typed causal-confidence label and never claims a confirmed driver without human-attached evidence — a single reviewed reference establishes chronology, not causation.
What happened
On 5 August 2024, Japan's Nikkei 225 fell more than 12% in a single session — its worst one-day fall since 1987 — as leveraged positions funded in cheap yen were unwound at speed. Equity volatility spiked globally and US index futures opened sharply lower before markets stabilised over the following days.
What was known then
At the time, the Bank of Japan had just raised rates in late July while a weak US jobs report had revived US slowdown worries. Traders knew enormous carry positions existed, but their size and the speed of forced unwinding only became apparent as the selloff unfolded.
Market reaction
Japanese equities fell double digits in one session, the yen strengthened sharply, volatility gauges spiked to levels rarely seen outside crises, and risk assets worldwide traded lower before recovering much of the fall within days.
What was uncertain
Whether the unwind marked the start of a broader deleveraging cycle or a positioning flush; how much carry exposure remained; and whether the US economy was genuinely rolling over.
What changed afterward
Markets recovered faster than many expected, and the episode became the reference case for how positioning — not news alone — can produce outsized single-day moves. Carry-trade exposure is now a standard question whenever the yen moves abruptly.
Why it still matters
It is the clearest recent example of a session where the honest answer to "why did markets move?" involved leverage and positioning rather than a single headline — exactly the distinction our typed causal-confidence labels exist to preserve.
Sources
Primary and official references reviewed for this entry.
◦ Bank of Japan (official)
◦ Federal Reserve (official)
Latest developments
Current coverage that genuinely overlaps this episode — nothing is linked for the sake of linking.
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