By David Russell, reporter at OptionMonsterNEW YORK-- Everyone has been worried about America's "fiscal cliff," but Monday investors focused on growth in China. OptionMonster's tracking systems detected a surge of call volume in the iShares FTSE China 25 Index ( FXI) exchange-traded fund, which has been quietly outperforming the S&P 500 and other emerging markets in the last three months. More than 68,000 November 37 calls were sold for 23 cents against open interest, indicating that an existing position was closed. An equal number of December 38 calls were then bought for 48 cents, so it looks as if the calls were rolled one month into the future. Calls lock in the price where investors can buy stocks and funds, so they can control moves for a fraction of the price of the shares. The drawback is that they expire, and Monday's trader was adjusting his or her position to keep from seeing the November contracts go to zero this Friday. The roll cost 25 cents and allows another five weeks to profit from upside in the fund. The ETF rose 0.25% to $36.55. Recent economic data from China has been improving, and Australia's refusal to cut rates last week reflected the growing strength in its biggest trading partner to the north. That could offset a weakening economic picture in Europe and concerns about higher taxes and less government spending in the United States. Total option volume was more than twice the daily average, with calls outnumbering puts by a bullish 5-to-1 ratio. Russell has no positions in FXI.