The Japanese yen is at its lowest level since February 2016.
The currency is down by 0.5% at 114.62 per dollar as of 8:31 a.m. ET.
The yen has been weakening against the dollar since early November as the election of Donald Trump has ignited a broad-based US dollar rally.
"The rising yields and equity markets weigh on the yen," wrote Marc Chandler, global head of currency strategy at Brown Brothers Harriman, in commentary.
Friday "could be the first session the dollar has spent entirely above JPY 114 since February," he added.
Earlier in the morning, the yen dipped below 115 per dollar.
Looking forward, a Morgan Stanley team led by Hans W. Redeker wrote that they think the dollar will continue appreciating against the yen.
"International USD shortages may become a more pressing issue going into the New Year, suggesting rising USD funding costs," they wrote in a note. "Currency hedges may become too expensive, but with the US capital markets staying attractive, we expect the USD to move higher against foreign-asset-holding currencies such as the JPY."
