The 2024 Yen Carry Unwind: Anatomy of a Global Shock

In the space of three weeks in late July and early August 2024, one of the largest macro positions in financial markets violently collapsed. The Japanese yen carry trade — borrowing cheaply in yen and investing in higher-yielding currencies and assets globally — had been growing for years on the back of ultra-loose Bank of Japan policy. When the BoJ raised rates on 31 July 2024 and then a weak US jobs report landed on 2 August, the unwind was sudden and savage. On 5 August 2024, the Nikkei 225 fell 12.4% — its worst single session since Black Monday in 1987. The VIX spiked above 60. USD/JPY crashed about 12% in three weeks. It was a global shock manufactured almost entirely by FX mechanics.

What is the yen carry trade?

The yen carry trade is a strategy in which investors borrow in Japanese yen — historically among the cheapest currencies to borrow in, given the Bank of Japan's decade-long near-zero rate policy — and deploy that capital into higher-yielding assets elsewhere. Those assets might be US dollars earning 5%, Mexican pesos, Brazilian reals, or simply US Treasuries. As long as the yen stays stable or weakens, the trade earns the interest rate differential. When the yen rises, the trade loses — sometimes catastrophically.

The arithmetic is straightforward:

For a full explanation of the mechanics and why carry trades "go up by the stairs and down by the elevator," see The Carry Trade Explained.

How did the 2024 unwind start?

By mid-July 2024, USD/JPY had climbed to 161.95 — the yen's weakest level against the dollar since 1986, according to market data. Carry trade positions had been building for years: the US Federal Reserve's rate-hiking cycle had kept the dollar-yen interest differential at multi-decade highs, making the trade extremely attractive and increasingly crowded.

The trigger was a two-part shock compressed into days:

Trigger 1 — BoJ rate hike, 31 July 2024. The Bank of Japan, under Governor Kazuo Ueda, raised its benchmark policy rate from the 0–0.1% range to approximately 0.25% — the highest level since 2008, as confirmed by the BoJ's official statement and CNBC's reporting. Ueda also indicated further hikes were possible if the economy developed as expected. This was not a surprise in isolation — but markets had priced only a modest chance of a hike that day.

Trigger 2 — US non-farm payrolls, 2 August 2024. US payrolls came in at just 114,000 versus an expected 175,000, and the unemployment rate jumped to 4.3%. This raised fears that the Fed had kept rates too high for too long and would need to cut aggressively — compressing the very rate differential that made the carry trade profitable.

The mechanics of a carry unwind

The reason carry trade unwinds are so violent is the self-reinforcing feedback loop they create. In a normal market sell-off, falling prices reduce demand and that's roughly the end of it. In a carry unwind, the mechanism amplifies itself:

1. JPY rises → loans become more expensive Investors who borrowed yen now need more of their investment returns to cover the loan. The trade is less profitable or actively loss-making.
2. Forced asset sales to repay yen To close the carry trade, investors sell their foreign assets and buy yen back. This selling drives down asset prices globally — equities, emerging-market currencies, crypto, anything that was funded by yen borrowing.
3. Yen rises further The wave of yen purchases to repay loans drives JPY higher still — which makes remaining carry positions even more loss-making, triggering yet more selling.
4. Volatility spikes → margin calls Rising volatility causes brokers and exchanges to increase margin requirements. Leveraged carry traders must post more collateral or liquidate. The VIX spike above 60 in August 2024 is a direct read of this process.

The BIS Bulletin No. 90 described it precisely: "an example of volatility exacerbated by procyclical deleveraging and margin increases." The BIS estimated roughly ¥40 trillion (about $250 billion) in yen-funded carry positions entering the event — making the available fuel for the unwind enormous.

The Nikkei's Black Monday echo

The Nikkei 225's 12.4% fall on 5 August 2024 was the index's worst single-session performance since Black Monday in October 1987 when it fell 14.9%. In absolute point terms, it was the largest single-day drop in the Nikkei's history: 4,451 points, surpassing even the October 1987 crash, as confirmed by The Japan Times and US News.

Why did the Nikkei fall so sharply? Several reasons compounded. Japanese equities had attracted enormous inflows from carry-funded investors: cheap yen made it attractive to borrow in JPY and buy Japanese stocks. When the carry trade unwound, those equity positions had to be liquidated. Additionally, the stronger yen hurt exporters directly — companies like Toyota and Sony earn significant revenues in dollars and euros; a stronger yen reduces the yen-value of those earnings.

The global ripple effect

The carry unwind did not stop at Japan's borders. The BIS Bulletin No. 90 documented that the Mexican peso was hit hardest among high-yielding investment currencies, followed by the Brazilian real and South African rand — all three popular carry-trade destinations funded in yen. Global equity indices fell sharply. Crypto markets sold off. The Swiss franc — another carry-trade funding currency — also appreciated sharply as positions were closed.

What this means for reading JPY's macro score

The 2024 unwind is a direct real-world illustration of why the JPY macro score on a currency strength meter deserves careful reading. For years, the yen's yield component dragged its score toward the bottom of the major-currency ranking — negative or near-zero rates make the yen a poor investment destination. But its safe-haven component has always been strongly positive, and its current account surplus gives it a structural bid.

When the yield gap between the yen and other currencies begins to close — as it did when the BoJ hiked to 0.25% and markets expected further moves — the carry trade's fundamental rationale shrinks. On Pip Theory's Macro Currency Strength Meter, this shift shows up as an improvement in JPY's yield score even from very low levels, which narrows the divergence that funded the carry trade in the first place.

The About & Methodology page details how the yield and safe-haven components interact in Pip Theory's scoring framework. For a deeper dive into carry trade mechanics generally — including the "crash risk" documented in the academic literature — see The Carry Trade Explained.

Three lessons from the August 2024 shock

1. Crowding amplifies moves beyond fundamentals The BIS estimated ~¥40 trillion in carry positions. When a trade is that crowded, a small fundamental shift can trigger a disorderly unwind — not because the fundamentals justify the move, but because everyone is forced to exit simultaneously. Positioning data (COT reports, CFTC figures) matters as much as the fundamental picture.
2. Funding currencies can have sudden violent reversals JPY had been weakening for years. The structure of the carry trade means the reversal, when it comes, is compressed and savage — "up by the stairs, down by the elevator." The [Swiss franc shock of 2015](/research/swiss-franc-shock-2015) is a structurally similar event for another funding currency.
3. Global macro events start in FX The Nikkei's 12.4% fall, the VIX spike, the EM currency sell-off — none of these were triggered by equity-specific or EM-specific news. They were triggered by a JPY appreciation caused by a BoJ rate decision. Currency strength is where global macro risk is priced first.

For the primary academic framework on carry trade crash risk, see the paper by Brunnermeier, Nagel, and Pedersen (2008), "Carry Trades and Currency Crashes" — directly relevant to understanding why the 2024 unwind unfolded the way it did. The BIS has also published a comprehensive Bulletin No. 90 on the August 2024 carry trade unwind that provides the authoritative post-mortem.

For historical context, the Plaza Accord shows the roots of the yen carry trade — the BoJ's rate cuts in response to yen appreciation after 1985 were the original source of cheap yen that global traders have exploited ever since.

Educational macro context only — not investment advice.