The dollar fell to its lowest level against the yen since May 1 and hit a six-month low against the Swiss franc on Wednesday as talk that U.S. President Donald Trump could face the threat of impeachment boosted safe-haven assets.
The dollar index, which tracks the U.S. currency against six peers and had scaled a 14-year peak of 103.82 on Jan. 3, fell 0.57 percent to its lowest level since Nov. 9, surrendering all of its "Trump bump" gains.
News emerged on Tuesday that Trump had asked his now-dismissed FBI chief James Comey to end the agency's investigation into ties between former White House national security adviser Michael Flynn and Russia.
That raised questions about whether Trump tried to interfere with a federal investigation, spurring speculation over the likelihood of an early exit from office for the former businessman.
The dollar fell blew through the 112 yen level, falling 1.92 percent to 110.97 yen. The dollar sank 0.75 percent against the Swiss franc, falling to its lowest since Nov. 9.