The Swiss franc, the go-to-flight-to-safety asset alongside gold, is losing its appeal it seems. A drop in risk in Europe and growing signs of economic stability in the U.S. are prompting some investors to re-evaluate. The Swiss National Bank put in a floor in September 2011 to hold the Swiss franc’s strength against the euro and maybe with a 3.6 percent advance this year sending the single currency to 1.25 Swiss francs and change that will also fall off the table. USDCHF three-month implied volatility, a gauge of expected price swings and rose to its highest since September on Monday. One-year risk reversals, protection against price swings, in the same pair have shown the highest demand for dollar calls, since June on some trading platforms. Some of the action reflects dollar bullishness but the other side is a bid for protection against a franc collapse. Tuesday the IMF said the SNB should unwind the large foreign currency reserves it built up to cap franc gains on any dips in the Swiss unit.