Yen Carry Trade and Leveraged ETFs Reignite 2024 Flash Crash Risk
N.R. Finch
The three conditions behind the August 2024 global flash crash — crowded yen carry trades, stretched tech valuations, and ballooning leveraged ETFs — are all reassembling, pushing second-half deleveraging risk above historical averages.
What actually happened in the August 2024 crash?
On August 5, 2024, Japan's Nikkei 225 plunged 12.4% in a single session — the worst day since Black Monday in 1987.
The VIX — the CBOE volatility index that tracks market fear — spiked above 65, its highest since the Covid sell-off.
The S&P 500 fell 3%, its worst day since September 2022. This means → the crash was not a local event but a global deleveraging chain running from Tokyo to New York.
Why is the yen carry trade dangerous again?
The yen is trading near a 40-year low, and the Bank of Japan has raised rates to 1%, the highest since 1995. In plain terms = the "borrow yen, buy dollar assets" carry trade is still crowded, but Japanese rate hikes are squeezing the spread that funds it.
The latest CFTC Commitments of Traders report shows speculative short positions exceeding 146,000 contracts — the second-largest weekly short in any week since July 2024. This means → a sharp yen rally would force mass short-covering, compressing the same spring that snapped last year.
Japan's Finance Minister Satsuki Katayama recently held a video call with US Treasury Secretary Scott Bessent to discuss possible currency intervention. The last time the US intervened in FX markets was the coordinated G7 action after the 2011 Fukushima disaster. This reflects a policy-level alert on yen volatility that has moved beyond watching to preparing.
How does the BIS explain the trigger mechanism?
The BIS — the central bank for central banks — reviewed the 2024 deleveraging path: the yen's long depreciation trend reversed sharply in July 2024, with USD/JPY dropping from around 161 to below 153.
The trigger was a hawkish BOJ rate hike combined with market expectations of currency intervention. Put simply = when everyone was betting the yen would keep falling, the central bank pushed the other way and a stampede followed.
The BIS concluded that the current market structure is highly similar to that period. This means → the same trigger conditions are already in place — all that is missing is the spark.
What role do tech valuations and leveraged ETFs play?
Since the start of 2026, the Philadelphia Semiconductor Index (SOX) has risen over 80%, while the S&P 500 gained roughly 8% over the same period. The S&P 500 tech sector's price-to-sales ratio is near 10×, a historical extreme.
JPMorgan Asset Management's Michael Cembalest noted in a recent report that leveraged ETFs — funds that use borrowing to amplify daily returns — must buy into rallies and sell into drops to maintain their target multiple, mechanically amplifying price momentum. He wrote: "Since early 2024, the market impact of leveraged semiconductor ETF rebalancing on global equities has grown fivefold."
JPMorgan strategist Nikolaos Panigirtzoglou added in a separate report that some previously extreme indicators have begun to pull back, but the overall leverage structure remains elevated. This means → leveraged ETFs are not the source of risk but its amplifier — once selling begins, they make the drawdown deeper and faster than it would otherwise be.
Which signals should investors watch in the second half?
Three factors coexist: crowded yen shorts + elevated tech valuations + expanding leveraged-ETF scale, pushing second-half deleveraging risk above historical averages.
In plain terms = a crash is not guaranteed, but the market's current "fragility level" is well above normal — the same magnitude of shock would cause more damage than usual.
Key leading signals to monitor: employment data (is the economy weakening?), yen price action (is carry-trade unwinding starting?), and volatility indicators such as VIX (is fear building beneath the surface?).
Content is for reference only, not financial advice.