to the S&P 500 instead of the S&P 100 ( OEX ). The change will occur on Sept,. 22nd of this year, yielding a more "robust and precise measure of expected volatility" and paving the way for CBOE futures trading of the VIX sometime in the 4th quarter of this year. "The new methodology for calculating the VIX will include a broader range of strike prices, rather than using only "at-the-money" index options."