The Japanese yen fell to levels not seen in 40 years against the US dollar, stirring concerns across markets as traders brace for the Bank of Japan's interest rate decision on Friday. The pressure on the yen has revived memories of the 2024 carry-trade unwind, which back then sent shockwaves through crypto markets.

In simple terms, the carry trade happens when investors borrow in a low-yield currency like the yen to invest in higher-yielding assets elsewhere. When the yen weakens sharply, it can lead to rapid unwinding of those positions, forcing traders to scramble and causing volatility. This dynamic not only impacts forex but spills over into cryptocurrencies, which often feel the ripple effects in risk sentiment.

Analysts warn the upcoming policy meeting could trigger a similar move as investors look for clues on whether the Bank of Japan will maintain its ultraloose stance or hint at tightening. Any unexpected change or reaffirmation might push the yen even lower or cause a sudden rebound. Given the yen's role as a funding currency, these shifts could rattle global markets, affecting everything from stocks to digital assets. Investors watching this scenario should be prepared for sharp moves as the central bank meeting approaches.