The Chicago Board Options Exchange Emerging Markets ETF Volatility Index, which tracks hedging costs on the iShares MSCI Emerging Markets fund, jumped to the highest level in 18 months versus a similar gauge for the Standard & Poor’s 500 Index. Investors in the ETF are bracing for more swings as they watch China’s deteriorating economy drag down developing markets amid the Federal Reserve’s intentions to tighten monetary policy for the first time in more than nine years. The MSCI Emerging Markets Index slid 1.1 percent Tuesday, dropping 20 percent below its September high, the threshold for a bear market. More