• New Campaign Touts ArcaEx's Recent Successes with Exclusive and Dual Listings
• Spotlights Pioneering/Trailblazing Companies that have Listed on ArcaEx

CHICAGO - May 31, 2005 - The Archipelago Exchange (ArcaEx), the nation's first totally open, all-electronic stock exchange, today announced the launch of a new advertising campaign around the exchange's listed companies. The campaign's focus is to raise awareness of ArcaEx as a listings venue among the issuer and investment banking communities and to spotlight recent trailblazing companies that have listed on ArcaEx and laid the groundwork for the exchange's more widespread emergence.

Since January 2005 the Archipelago Exchange has been the home to a number of new exclusive and dual listings with AIG, optionsXpress, American Dairy and Metropolitan Health Networks having listed.

Margaret Nagle, Managing Director of Archipelago, commented, "We have been pleased with the success of our recent efforts to brand the Archipelago Exchange against a broader audience. Initially this effort included raising awareness among corporate issuers with our focused 'Numbers this Big are Hard to Ignore' advertising campaign."

Nagle added, "With this new campaign- 'Stock Market Pioneers'- we thought it was time to send a more direct message to corporate issuers by recognizing the companies that have realized the benefits of listing on the Archipelago Exchange."

David Sigel, Group Account Director of Fallon Minneapolis, commented, "ArcaEx is working to extend its strong position among trading professionals to those members of the corporate community who make listings decisions. This new advertising campaign 'Stock Market Pioneers' recognizes some of the visionary companies who have chosen to list on ArcaEx, realizing the benefits of this new breed of fully electronic exchange."

Starting in June 2005, the campaign's print component will run in publications such as the Wall Street Journal, Barron's and Investor's Business Daily. A radio component of the campaign will run on Sirius Satellite and XM Radio.

Fallon Minneapolis created the campaign and is Archipelago's Agency of Record.

About ArcaEx

Archipelago Holdings Inc. (PCX: AX) operates the Archipelago Exchange (ArcaEx®), the first totally open all-electronic stock exchange in the United States to trade Nasdaq-listed equity securities and exchange listed equity securities, including those traded on the New York Stock Exchange®, American Stock Exchange® and Pacific Exchange®. ArcaEx offers corporate issuers and investors the advantages of meeting directly, without intermediaries within a fully electronic and totally transparent environment. ArcaEx is a facility of and regulated by the Pacific Exchange, a registered exchange. ArcaEx was approved by the Securities and Exchange Commission in October 2001 and ArcaEx began trading operations in March 2002. The Archipelago ECN, a precursor to ArcaEx, was one of the four original ECNs, formed in December 1996 with Townsend Analytics. For more information please visit www.arcaex.com.

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 the Company's filings with the Securities Exchange Commission, including its Report on Form 10-K for the fiscal year ending December 31, 2004 which is available on the Company's website at http://www.archipelago.com. You should not place undue reliance on forward-looking statements, which speak only as of the date of this press release. Except for any obligation to disclose material information under the Federal securities laws, Archipelago undertakes no obligation to release publicly any revisions to any forward-looking statements to reflect events or circumstances after the date of this press release.

Archipelago Contacts:
Margaret Nagle
312-442-7083