The franc, often used to finance so-called carry trades because of the country's low borrowing costs, also declined against the Brazilian real and the South Korean won. The dollar was supported before a Federal Reserve meeting today at which policy makers may leave interest rates unchanged and highlight concern about inflation.
Against the dollar, the franc dropped to 1.0521 by 11:16 a.m. in Zurich, from 1.0483 yesterday, extending its loss this quarter to 3.1 percent. It reached 1.0542 earlier, the weakest level since May 19. Against the euro, it was at 1.6308, from 1.6327.
The Swiss Market Index of the biggest companies climbed 1.2 percent, and the Dow Jones Stoxx 600 Index advanced 1.7 percent. Futures on the Standard & Poor's 500 Index expiring in September added 0.7 percent.
Gains in stock markets prompted investors to add to carry trades, where they get funds in a country with low borrowing costs and invest in those with higher interest rates, earning the spread between them.
Switzerland's target rate of 2.75 percent is the third lowest among industrialized nations, after Japan and the U.S. The equivalent rate for the 15 nations sharing the single currency is 4.25 percent.