ISE Reports Monthly Volume for September 2006.

Average Daily Volume of 2.4 Million Contracts, up 25.3% from September 2005

NEW YORK -- The International Securities Exchange (NYSE:ISE) today reported that average daily trading volume for equity and index options contracts for September 2006 increased 25.3% to 2.4 million contracts as compared to 1.9 million contracts during the same period in 2005. Total equity and index options volume for the month increased 19.3% to 47.3 million contracts from 39.6 million contracts in the same year-ago period.

On a year-to-date basis, average daily trading volume of equity and index options increased 38.6% to 2.3 million contracts traded as compared to 1.7 million contracts traded in the prior year. Total equity and index volume through September 2006 increased 37.9% to 439.8 million contracts from 319.0 million contracts in the same period last year.

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Dividend Trade Activity

Our market share statistics continue to be negatively impacted by trading activity related to dividend trades among certain options market makers. These trades temporarily inflate and distort trading volume and market share when transacted. If the volume from the largest dividend trades were excluded from the data, our market share of equity options for the month of September would increase to 33.3% from 32.3%, an increase of 1.0 market share point. On a year-to-date basis, our market share would increase to 33.2% from 32.2%, an increase of 1.0 market share point, if the volume from the largest dividend trades were excluded. The exclusion of dividend trades from total industry volume data presents a more relevant measure of the relative trends in our business.

Monthly Highlights

* ISE was the largest U.S. equity options exchange in September.

* On September 8, 2006, ISE successfully launched its MidPoint Match[TM] platform, the first product to debut on the ISE Stock Exchange, LLC. The MidPoint Match platform performed flawlessly and ISE members reacted positively to the system's trading structure and execution speed. Trading was initiated in ten stocks.

* On September 14, 2006, ISE's Board of Directors declared a quarterly dividend of $0.05 per outstanding share of its Class A Common Stock, payable on September 29, 2006 to holders of record as of the close of business on September 22, 2006.

* On September 20, 2006, ISE announced its intent to create and list new foreign currency options, called ISE FX Options[TM], which will provide retail and institutional investors with a new investment strategy that will enable them to express their views on the strength or weakness of the U.S. Dollar relative to other currencies. ISE will initially list the following four currency pairs: USD/EUR, USD/GBP, USD/JPY, and USD/CAD. Trading in ISE FX Options is expected to begin in the first quarter of 2007, pending regulatory approvals.

* On September 22, 2006, ISE stock listed an additional 280 stocks on its MidPoint Match platform.

* On September 27, 2006, ISE announced the official launch of its Historical Options Tick Data[TM] offering (ISE HOT Data[TM]), the first in its suite of new market data products.

* On September 29, 2006, ISE added 330 stocks to its MidPoint Match[TM] platform, bringing the total number of equities traded to 640 representing more than 75% of the total market capitalization of U.S. traded securities. Included among the names traded are companies in the S&P 500, select ETFs, several lower-priced stocks, and ISE.

* ISE traded more volume than any other options exchange in 672 of 941 issues in its listings.

ISE Background

The International Securities Exchange, LLC (ISE) is a wholly-owned subsidiary of International Securities Exchange Holdings, Inc. (ISE Holdings). ISE operates an innovative securities market, founded on the principle that technology and competition create better, more efficient markets for investors. ISE is the largest equity options exchange and is among the leading options exchanges in the world. ISE developed a unique market structure for advanced screen-based trading systems and in May 2000 launched the first fully electronic US options exchange. The ISE Stock Exchange launched in September 2006 with strategic partners and offers an innovative MidPoint Match platform, which will be followed by a fully integrated displayed Best Bid Offer market in the fourth quarter. ISE Holdings is also a majority owner of Longitude LLC, which operates an innovative platform for events markets trading. Additionally, ISE offers enhanced market data products for sophisticated investors.

ISE continually enhances its trading systems and develops new products, including index options and market data, to provide investors with the best marketplace and investment tools to trade smarter. For more information about ISE, its options products and its technology, visit www.iseoptions.com, for more information about the ISE Stock Exchange, visit www.isestock.com and for more information about Longitude, visit www.longitude.com.

Certain matters discussed in this press release are "forward looking statements" intended to qualify for the safe harbor from liability established by the Private Securities Litigation Reform Act of 1995. These statements relate to future events or our future financial performance, and involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements, to be materially different from those contemplated by the forward looking statements. We undertake no ongoing obligation, other than that imposed by law, to update these statements. Factors that could affect our results, levels of activity, performance or achievements and cause them to materially differ from those contained in the forward looking statements can be found in our filings with the Securities and Exchange Commission, including our annual report on Form 10-K, current reports on Form 8-K and quarterly reports on Form 10-Q.