BlackRock has cautioned that an accelerated pace of interest rate hikes by the Bank of Japan could prompt domestic investors to repatriate funds in search of higher returns, potentially driving up global bond yields.

Strategists at the firm's research unit, including Wei Li, noted in a report that the "spillover effects are tangible," highlighting the risk of a feedback loop forming in bond markets. They pointed out that Japan currently offers a substantial risk-free yield, a notable shift from past decades.

For years, ultra-low domestic yields pushed Japanese investors to allocate capital overseas in pursuit of income. However, as interest rates climb, a portion of that capital may flow back into the Japanese market, reshaping global investment flows.

Adding to the complexity, Japan's economic conditions demand tighter monetary policy due to persistent inflation. Yet, expanding government spending and a debt burden exceeding twice the nation's GDP make higher interest rates increasingly costly to implement. The report also emphasized that an overly accommodative policy stance has placed downward pressure on the yen.

Should the yen weaken further, it could lead Japanese authorities to sell overseas assets, including US Treasuries, to support the currency, which would likely exert additional upward pressure on US bond yields. This dynamic creates a two-way interaction: rising US rates could weaken the yen, forcing the Bank of Japan to accelerate its own tightening, while higher Japanese rates might attract more capital back home, reducing demand for US debt and thereby pushing up American borrowing costs.