Lien argues that the yen has been strengthening due to its status as a funding currency – the yen has acted as a cheap source of borrowed money put toward more speculative trades, but as uncertainty rises, investors are unwinding bets and covering shorts on the yen.

While the USD has been weakening against other developed currencies, the greenback has strengthened against emerging market currencies, notably against commodity producing countries and China.

Consequently, the actively managed WisdomTree Bloomberg U.S. Dollar Bullish Fund (NYSEArca: USDU), which tracks the USD against a broader basket of developed and emerging market currencies, gained 0.3% Friday. USDU includes a 9.7% tilt toward the Mexican peso, 3.4% to the South Korean won, 3.1% to the Chinese yuan and 2.1% to the Brazilian real.

CurrencyShares Japanese Yen Trust

Max Chen contributed to this article.