套利交易之所以持續吸引資金，根本原因在於日本與其他主要經濟體之間巨大的利差。日本政策利率僅為1%，遠低於多數已開發國家，加上財政方面的隱憂，日圓承受持續的貶值壓力。高盛策略師指出，日圓套利頭寸「減少了，但並未消失」。今年以來，以日圓融資做空、買入哥倫比亞披索、土耳其里拉和挪威克朗等高息貨幣的交易回報率均超過10%。日本投資者自身也在干預後日圓短暫反彈期間大舉買入外國資產，創下兩年多來最高紀錄。
展望未來，日本首相高市早苗政府據報支持日本央行在九月或十月提前加息，以應對日圓疲軟。然而，即便加息一碼，也難以大幅收窄與美國的利差。美國財長貝森特重申支持穩定日圓，警告日圓疲軟可能引發亞洲貨幣連鎖貶值。市場人士認為，只要日本央行落後於利率曲線，以日圓融資的套利交易就會持續繁榮，但干預風險也意味著波動性將加大，投資者需警惕被迫快速平倉的可能。
Japan's historic joint intervention with the United States to support the yen has proven largely ineffective. The currency has erased half of its intervention-driven gains, sliding back toward 160 per dollar. Investors view each round of intervention as a fresh opportunity to sell the yen at more favorable levels and re-enter carry trades. While hedge funds have reduced their bearish yen bets, market participants including JPMorgan Private Bank and State Street Bank & Trust report that real-money accounts remain positioned for carry trades, selling the yen against a range of G-10 currencies such as the Australian dollar, euro, and US dollar.
The fundamental driver behind the persistent yen weakness is the wide interest-rate differential between Japan and other developed economies. Japan's 1% policy rate makes the yen one of the cheapest currencies to borrow, enabling investors to fund purchases of higher-yielding assets. Goldman Sachs notes that carry positions are "diminished, not finished." Shorting the yen against currencies like the Colombian peso, Turkish lira, and Norwegian krone has returned over 10% this year. Even Japanese domestic investors have seized the post-intervention bounce to buy foreign assets at the highest level in more than two years.
Looking ahead, Prime Minister Sanae Takaichi's government reportedly supports a near-term Bank of Japan rate hike, likely in September or October, though a single quarter-point increase would do little to narrow the gap with US rates. Treasury Secretary Scott Bessent has pledged to do "whatever it takes" to support the yen, warning that its weakness risks broader Asian currency depreciation. Market strategists believe that as long as the BOJ remains behind the curve, yen-funded carry trades will continue to flourish, albeit with greater volatility driven by the ever-present threat of further intervention and forced position unwinding.