The U.S. dollar index , which measures the greenback against a basket of rivals, stayed mostly flat at 105.17 as traders awaited the Fed's rate decision.
Attention stayed fixed on the yen as U.S. and Japanese authorities heaped on fresh comments about the possibility of intervention.
The yen last sat around 147.83 versus the greenback, off Tuesday's low of 147.92 though hovering near the 10-month trough against the dollar ahead of the FOMC announcement.
Elsewhere in Asia, the offshore yuan was largely unchanged after China met market expectations by keeping its benchmark lending rates unchanged on Wednesday, but later ticked down 0.1% to 7.3103 per dollar.
The Australian dollar , a proxy for China growth, fell nearly 0.1% in the Asian afternoon, while the New Zealand dollar was flat, down from Tuesday's two-week high against the dollar.
Persons:
Dado Ruvic, Carol Kong, Masato Kanda, Janet Yellen, Brigid Riley, Gerry Doyle
Organizations:
REUTERS, Rights, Federal Reserve, U.S, Commonwealth Bank of Australia, Washington, Treasury, Bank of Japan's, New Zealand, Bank of England, bitcoin BTC, Thomson
Locations:
Japan, U.S, Asia, China, bitcoin