CBOE Introduces New Implied Correlation Index Based On The S&P 500 Index - Plans to Develop Realized Correlation Products - Add New Analytical Tools to Award-Winning Website

CHICAGO, June 2, 2008 - The Chicago Board Options Exchange (CBOE) announced today that beginning on Wednesday, June 4, 2008, the Exchange will begin publishing data associated with a new volatility-related benchmark index, the CBOE S&P 500 Implied Correlation Index tied to two different option maturities - January 2009 (ticker symbol ICJ) and January 2010 (ticker symbol JCJ).

The CBOE S&P 500 Implied Correlation Index is a measure of the expected average correlation of components of the S&P 500 Index (SPX).Using SPX options prices, in concert with the prices of options on the 50 largest stocks in the S&P 500 Index, the CBOE S&P 500 Implied Correlation Index offers significant insight into the relative cost of SPX options compared to the price of those options on the individual stocks that comprise the S&P 500.

CBOE plans to disseminate ICJ and JCJ values once per day after the close of trading.Each day, CBOE will publish the index values, and provide on its website the correlation index input values; i.e. the implied volatilities for SPX options and options on each of the top 50 stocks in the S&P 500 Index.Historical information dating back to 2003 will also be available.

In addition to the new Implied Correlation Index, CBOE plans to develop the first exchange-traded realized correlation products tied to the S&P 500 Index.CBOE also plans to add new, interactive volatility-based content on cboe.com at a later date.

"As the leading innovator in the volatility space, CBOE is pleased to add yet another important new benchmark index to CBOE's suite of volatility products.Our new implied correlation index, will offer greater depth of information by providing a pricing snapshot of SPX options versus individual equity options on companies within the S&P 500 Index itself, and pave the way for the next generation of volatility products," said CBOE Chairman and CEO William J. Brodsky.

A complete overview of the CBOE S&P 500 Correlation Index, including methodology, components and pricing information, can be found at www.cboe.com/ImpliedCorrelation.

CBOE, the largest U.S. options marketplace and creator of listed options, is regulated by the Securities and Exchange Commission (SEC).For additional information about the CBOE and its products, access the CBOE website at www.cboe.com.