The Japanese yen and bitcoin are trading in closer tandem than ever before.

Bitcoin traders may need to expand their macro focus beyond the dollar, as the cryptocurrency’s link to the Japanese yen has strengthened to record levels.

According to TradingView data, the 90-day correlation between bitcoin and Pepperstone’s Japanese yen index has climbed to 0.86, the highest level ever recorded. Such a reading suggests the two assets have been moving in near lockstep over the past three months.

That relationship implies roughly 73% of bitcoin’s price fluctuations during the period can be explained by movements in the yen. The figure, known as the coefficient of determination, is calculated by squaring the correlation coefficient and offers a simple gauge of how closely the assets track one another.

Pepperstone’s JPY Index, or JPYX, is a currency index CFD that measures the yen’s performance against a basket of four major currencies: the euro, U.S. dollar, Australian dollar and New Zealand dollar.

The unusually strong alignment suggests bitcoin, long regarded as a largely independent asset, has recently been trading under the influence of Japanese currency dynamics. Over the past 90 days, BTC has tended to rise and fall alongside the yen, eroding its appeal as a portfolio diversifier and turning what was once framed as “digital gold” into a leveraged expression of yen exposure.

Even so, such correlations are often temporary. Links between cryptocurrencies and traditional assets such as currencies and equities have a history of breaking down as market conditions evolve.

Bitcoin peaked in early October and declined over the following two months, a move that coincided with an extension of the yen’s broader downtrend. Selling pressure in both markets began to ease after mid-December.

The yen has been weakening since April last year amid rising concerns about Japan’s fiscal sustainability, which have pushed government bond yields higher. With a debt-to-GDP ratio near 240%, Japan is among the most indebted economies globally, although the majority of its debt is held domestically.

That debt burden leaves the Bank of Japan with limited policy flexibility. Raising interest rates would lift debt-servicing costs and strain public finances, while keeping rates low risks further depreciation of the yen.

Some market participants argue that Japan’s fiscal stress is already being reflected in currency markets through a sharply weaker yen, and that only a potential U.S. recession may offer Japan temporary relief.