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ArcaEx Releases December 2004 Transaction Volume Data

Date 11/01/2005

Archipelago Holdings, Inc. (PCX: AX) today announced its December 2004 market transaction volume data for the Archipelago Exchange ("ArcaEx"). Specifically, in NYSE - listed equity securities, ArcaEx's total trading market share was 2.3% in December 2004, up from 1.2% in December 2003 and down slightly from 2.4% in November 2004.

In AMEX-listed equity securities, ArcaEx's total trading market share was 23.2% in December 2004, up from 14.4% in December 2003 and down from 25.9% in November 2004. ArcaEx's ETF total monthly share volume showed continued year- over-year growth with 1,401 (millions of shares) having traded in December 2004 compared to 654.4 (millions of shares) traded in December 2003 and down from 1,557.8 (millions of shares) in November 2004.

In AMEX-listed equity securities, ArcaEx's total trading market share was 23.2% in December 2004, up from 14.4% in December 2003 and down from 25.9% in November 2004. ArcaEx's ETF total monthly share volume showed continued year- over-year growth with 1,401 (millions of shares) having traded in December 2004 compared to 654.4 (millions of shares) traded in December 2003 and down from 1,557.8 (millions of shares) in November 2004.

In Nasdaq-listed equity securities, ArcaEx's total trading market share was 22.6% in December 2004 down from 27.7% in December 2003 and 23.7% in November 2004. Both AMEX and Nasdaq market share figures reflect the recent change in listings venue from AMEX to Nasdaq for QQQ (see ArcaEx market share in QQQQ for December 2004 in "ArcaEx Most Active December 2004" chart below).

                                               December   November   December
                                                   2003       2004       2004
     Total monthly volume of Nasdaq-listed
     equity securities (millions of shares)    36,014.2   38,856.3   45,454.6
     ArcaEx monthly volume of Nasdaq-listed
     equity securities (millions of shares)(1)  9,983.9    9,203.0   10,280.5
     ArcaEx share of total monthly volume of
     Nasdaq-listed  equity securities (%)(2)       27.7%      23.7%      22.6%
     Total  monthly volume of NYSE-listed
     equity securities (millions of shares)    35,565.0   39,634.4   40,888.7
     ArcaEx monthly volume of NYSE-listed
     equity securities (millions of shares)(1)    410.6      952.3      942.3
     ArcaEx share of total monthly volume of
     NYSE-listed  equity securities (%)(2)          1.2%       2.4%       2.3%
     Total  monthly volume of AMEX-listed
     equity securities (millions of shares)     6,230.0    6,654.7    4,942.8
     ArcaEx monthly volume of AMEX-listed equity
     securities (millions of shares) (1)          895.2    1,721.1    1,146.6
     ArcaEx share of total monthly volume of
     AMEX-listed equity securities (%)(2)          14.4%      25.9%      23.2%
     ArcaEx ETF total monthly share volume
     (millions of shares)                         654.4    1,557.8    1,401.0
     ArcaEx monthly customer order volume matched
     internally (%)(3)                             85.6%      87.6%      87.6%
     ArcaEx monthly customer order volume
     routed out  (%)(3)                            14.4%      12.4%      12.4%
     Number of trading days in period                22         21         22

                       ArcaEx Most Active December 2004

                          Symbol                  Share Volume    Market Share
     Sirius Satellite Radio           (SIRI)       561,256,472         16.8%
     Microsoft(R)                     (MSFT)       520,514,120         28.2%
     Nasdaq-100 Index(R)              (QQQQ)       455,108,158         24.2%
     Intel (R)                        (INTC)       409,800,359         27.2%
     Oracle(R)                        (ORCL)       296,165,264         25.7%
     Cisco Systems(R)                 (CSCO)       293,090,158         31.1%
     SPDR (R)                          (SPY)       274,773,091         30.2%
     Semiconductor Holdrs(sm)          (SMH)       274,744,400         56.5%
     Sun(R) Microsystems              (SUNW)       242,872,837         26.5%
     Applied Materials(R)             (AMAT)       148,876,115         23.2%

Additional information on ArcaEx daily, weekly and monthly trading transaction volumes is publicly available in real time through the ArcaVision website accessible via http://www.archipelago.com. Additional data and enhanced functionality can be obtained through a free subscription to ArcaVision. Investors and ArcaEx clients can subscribe to ArcaVision at http://www.arca-vision.com.

(1) For purposes of calculating monthly transaction volume on ArcaEx, we include all shares that are "handled" on ArcaEx for the month. Handled shares include both shares that are bought and sold during the month within our internal liquidity pool and shares that are routed to external market centers for execution.

(2) ArcaEx monthly market share is calculated based on the number of shares handled on the ArcaEx system during the month as a percentage of total monthly volume. Total monthly volume is based on the number of shares of equity securities traded during the month on Nasdaq, AMEX or the NYSE, including if applicable exchange-traded funds, in each case as reported to the consolidated tape. The "consolidated tape" is the system that continuously provides the last sale price and volume of securities transactions in listed securities to the public.

(3) In computing the percentage of monthly customer order volume matched internally and the monthly percentage of customer order volume routed out, we calculate the percentage based on the volume of individual customer orders, not the volume of matched trades (i.e., only counting one side of a matched transaction). For example, we calculate two customer orders matched internally on our system as two customer orders matched internally, and we include the volume of both the buy order and the sell order in computing our percentages of monthly customer order volume matched internally and routed out. We calculate one customer order routed to an external market center (which will be matched with an order at that other market center) as one outbound trade or one customer order. We calculate one customer order routed to us from an external market center and matched with an order on our system as one inbound trade or one customer order.

About Archipelago Holdings

Archipelago Holdings (PCX: AX) operates The Archipelago Exchange(R) (ArcaEx(R)) the first totally open all -- electronic stock exchange in the United States. ArcaEx trades all Nasdaq-listed equity securities and exchange listed equity securities, including those listed on the New York Stock Exchange(R), American Stock Exchange(R), and Pacific Exchange(R). In addition to offering core execution services, ArcaEx provides corporate clients with listing services and innovative data products. In 2004, Archipelago launched ArcaVision to provide corporate and trading clients with more transparent market data, analytical tools and access to market-wide and ArcaEx specific trading information. Archipelago Holdings completed its initial public offering in August 2004. For more information please visit http://www.archipelago.com.

ArcaEx's, past transaction performance is not necessarily indicative of its future results. Periodically, ArcaEX's transaction performance will experience fluctuations due to unforeseen factors effecting trading activity, including seasonality, general economic, political and market conditions, unforeseen market closures or other disruptions in trading. A description of the factors that may influence ArcaEx's volume of securities transactions are identified in Archipelago's Prospectus, dated August 12, 2004.

Certain statements in this press release may contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements are based on Archipelago's current expectations and involve risks and uncertainties that could cause Archipelago's actual results to differ materially from those set forth in the statements. There can be no assurance that such expectations will prove to be correct. Factors that could cause Archipelago's results to differ materially from current expectations include: general economic and business conditions, industry trends, competitive conditions, regulatory developments as well as other risks or factors identified in Archipelago's Prospectus, dated August 12, 2004, and form 10-Q dated November 9, 2004, each of which are filed with the Securities and Exchange Commission, and available on Archipelago's website: http://www.archipelago.com.