美国财政部与日本央行近日联合干预外汇市场以支撑日元，这是2011年以来美国首次对日元汇率进行干预[1]。日本央行在周四和周五分别投入约530亿美元和360亿美元进行市场操作，使日元兑美元汇率从163的40年低位升至157左右[1]。
美国支持此举的核心考量在于防范系统性金融风险[1]。日本持有约1.1万亿美元的美国国债，同时日本机构还持有约1.2万亿美元的美国股票[1]。若日元继续贬值导致日本大幅抛售美债，将对美国金融市场造成冲击[1]。此外，规模超过1万亿美元的日元套利交易若大规模平仓，也可能引发市场危机[1]。
当前美国面临的债务压力加剧了这一风险[1]。美国财政赤字占国内生产总值约6%，国债总规模接近40万亿美元，30年期国债收益率已达2007年以来水平[1]。为应对流动性需求，美联储已扩大回购便利额度，允许日本央行以美国国债作为抵押获得美元流动性[1]。
The U.S. Treasury Department and Bank of Japan have jointly intervened in foreign exchange markets to support the yen, marking the first time the United States has directly intervened in the yen exchange rate since 2011 [1]. The Bank of Japan deployed approximately $530 billion on Thursday and roughly $360 billion on Friday to strengthen the yen through purchases of the currency and sales of euros [1]. These coordinated efforts have strengthened the yen from a 40-year low of 163 against the dollar to around 157 [1].
The intervention addresses significant financial stability concerns. Japan holds approximately $1.1 trillion in U.S. Treasury bonds and roughly $1.2 trillion in American equities, creating potential systemic risk should these positions require liquidation [1]. Japanese institutions are also heavily exposed through currency carry trades exceeding $1 trillion, which could trigger market instability if unwound at scale [1]. The Federal Reserve has expanded its repo facility to provide dollar liquidity, allowing the Bank of Japan to use U.S. Treasury securities as collateral [1]. These measures reflect U.S. concerns that a sharply weakening yen could force Japan to divest substantial holdings of American assets, while broader financial instability stemming from yen carry trades could have global implications amid elevated U.S. fiscal pressures, including a budget deficit representing approximately 6 percent of GDP and national debt approaching $40 trillion [1].