The Swiss franc tumbled to 18-month lows against the dollar in early trading on Tuesday as a rally in the US currency picked up steam, but the franc held steady against the euro.
Speculators have compounded gains in the dollar in recent weeks, betting that the US currency rally will continue, driven in part by corporate buying as companies repatriate profits.
Investors mostly ignored Monday's better-than-expected showing in Swiss unemployment, which edged lower in seasonally adjusted terms to 3.7 percent in October versus 3.8 percent in September.
The numbers indicated that a recovery in the Swiss economy was underway, backing up recent hawkish statements by the Swiss National Bank, which is preparing for its next meeting to decide interest rates on December 15.
Markets widely expect the SNB to raise key rates by 25 basis points.
The dollar last traded at 1.3159/61 Swiss francs from 1.3080/85 in late trading in Europe on Monday. The euro stood mostly unchanged at 1.5426/30 francs from 1.5423/28 francs.