ISE Reports Monthly Volume for February 2006; Average Daily Volume of 2.4 Million Contracts, Up 38% from February 2005

The International Securities Exchange, Inc. (NYSE:ISE)
today reported that average daily trading volume for equity and index
options contracts for February 2006 increased 37.9% to 2.4 million
contracts as compared to 1.7 million contracts during the same period
in 2005. Total equity and index options volume for the month increased
37.9% to 44.8 million contracts from 32.5 million contracts in the
same year-ago period.
   On a year-to-date basis, average daily trading volume of equity
and index options increased 44.0% to 2.5 million contracts traded as
compared to 1.8 million contracts traded in the prior year. Total
equity and index volume through February 2006 increased 44.0% to 98.6
million contracts from 68.5 million contracts in the same period last
year.
   As was the case in prior months, we witnessed trading activity
among options market makers on the Philadelphia Stock Exchange and
Pacific Exchange related to dividend trades whereby traders continued
to profit at the expense of investors who failed to exercise their
call options immediately prior to a stock going ex-dividend. If the
volume from the largest dividend trades were excluded from the data,
our market share of equity options for the month of February would
increase to 34.9% from 33.8%, an increase of 1.1 market share points.
On a year-to-date basis, our market share would increase to 34.7% from
32.9%, an increase of 1.8 market share points, when the volume from
the largest dividend trades was excluded. The exclusion of dividend
trades from total industry volume data presents a more relevant
measure of the relative trends in our business.

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Equity and Index Options Volume Statistics

                     Current Month               Year-to-Date
                                     %                           %
(000s)          Feb-06    Feb-05   Change    Feb-06   Feb-05   Change
----------------------------------------------------------------------
ISE Average
 Daily Volume  2,356.3   1,709.2    37.9%   2,528.5   1,756.2   44.0%
ISE Total
 Volume       44,770.2  32,474.5    37.9%  98,612.8  68,493.7   44.0%
Industry
 Average
 Daily Volume  7,525.1   5,593.7    34.5%   8,234.8   5,736.4   43.6%
Market Share     31.3%     30.6%   0.7 pts    30.7%     30.6%  0.1 pts
----------------------------------------------------------------------
ISE Market                                              
 Share:
 Customer        32.4%     31.0%   1.4 pts    32.3%     30.9%  1.4 pts
ISE Market                                              
 Share: Firm     27.1%     21.8%   5.3 pts    25.4%     20.4%  5.0 pts
ISE Market                                          
 Share:
 Market Maker    31.5%     32.4%  (0.9) pts   30.8%     33.0% (2.2)pts
----------------------------------------------------------------------


Equity Options Volume Statistics

                     Current Month               Year-to-Date
                                     %                           %
(000s)          Feb-06    Feb-05   Change    Feb-06   Feb-05   Change
----------------------------------------------------------------------
ISE Average
 Daily Volume  2,329.3   1,705.6    36.6%   2,498.7   1,754.3   42.4%
ISE Total
 Volume       44,257.1  32,406.8    36.6%  97,448.8  68,417.7   42.4%
Industry
 Average
 Daily Volume  6,900.9   5,130.8    34.5%   7,587.4   5,275.5   43.8%
Market Share     33.8%     33.2%   0.5 pts    32.9%     33.3% (0.3)pts
----------------------------------------------------------------------
ISE Market                                                     
 Share:
 Customer        34.7%     33.3%   1.4 pts    34.4%     33.2%  1.2 pts
ISE Market                                              
 Share: Firm     30.2%     24.6%   5.6 pts    28.1%     22.9%  5.2 pts
ISE Market                                                   
 Share:
 Market Maker    33.9%     35.3%  (1.4) pts   33.0%     35.8% (2.8)pts
                                          
----------------------------------------------------------------------


Index Options Volume Statistics

                     Current Month               Year-to-Date
                                     %                           %
(000s)          Feb-06    Feb-05   Change    Feb-06   Feb-05   Change
----------------------------------------------------------------------
ISE Average
 Daily Volume     27.0       3.6      N/M      29.8       1.9     N/M
ISE Total
 Volume          513.1      67.7      N/M   1,164.0      76.0     N/M
Industry
 Average
 Daily Volume    624.3     462.9    34.8%     647.5     461.0   40.5%
Market Share      4.3%      0.8%   3.5 pts     4.6%      0.4%  4.2 pts
----------------------------------------------------------------------
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   Monthly Highlights

   --  ISE was the largest U.S. equity options exchange in February.

   --  ISE set a new record for the single largest equity options
        transaction at the exchange when 165,000 Microsoft October 30
        calls traded at $0.40 on February 23, 2006 by one of its
        Electronic Access Members (EAM).

   --  ISE traded more volume in 629 of 847 issues in its listings
        than any other options exchange.

   ISE Background

   The International Securities Exchange, the world's largest equity
options exchange, was founded on the principle that technology fosters
and infuses new efficiencies and operational innovations into
securities trading. After developing an innovative market structure
that integrated auction market principles into an advanced
screen-based trading system, ISE launched the first fully electronic
US options exchange in May 2000. ISE continually enhances its trading
systems to provide investors with the best marketplace to execute
their options orders.
   For more information about ISE, its products and its technology,
visit www.iseoptions.com.

   This press release contains "forward looking statements." 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
registration statements on Form S-1, current reports on Form 8-K and
quarterly reports on Form 10-Q, as amended.