Dollar Weakness Fuels Yen Carry Trade Surge

Investors have flooded back into yen-funded carry trades, betting on continued dollar weakness and Japan's low borrowing costs. The strategy involves borrowing Japanese yen at the Bank of Japan's 1% interest rate, converting it to higher-yielding currencies like the US dollar, and investing in assets such as US Treasuries or emerging market bonds.

So far this year, carry trade strategies have returned around 18%, outperforming other systematic approaches. The greenback has fallen roughly 10% against major currencies since early 2025, driven by US fiscal anxieties, policy unpredictability, and shifting global capital flows.

The yen itself is trading at levels not seen in decades, with a weak yen benefiting carry traders as it makes the currency borrowed cheaper relative to investments. Hedge funds have been active participants, rebuilding their short bets on the yen after initially halving them earlier this year.

However, the core risk lies in a sudden appreciation of the yen, which could trigger a rush to close positions and amplify volatility across foreign exchange markets, equities, and bonds. The Bank of Japan remains a wild card, with any signal to tighten monetary conditions or intervene in currency markets potentially sparking a cascade.