NASDAQ OMX Group (NDAQ)

EXPLANATORY NOTE

This Current Report on Form 8-K/A, or Form 8-K/A, dated August 1, 2008, amends the Current Report on Form 8-K filed by The NASDAQ OMX Group, Inc., or NASDAQ OMX, on July 29, 2008, concerning the acquisition of the Philadelphia Stock Exchange, Inc. and Subsidiaries, or PHLX, occurring on July 24, 2008. This Form 8-K/A includes the required historical financial information of PHLX and the required pro forma financial statements of the combined entity, each as required by Item 9.01 of Form 8-K. In addition, the required historical financial information of OMX AB (publ), or OMX, is also included in this Form 8-K/A. The business combination of The Nasdaq Stock Market, Inc. with OMX and the acquisition of a 33 ¹/3% interest in the Dubai International Financial Exchange, or DIFX, occurred on February 27, 2008 (collectively, the Transactions). As such, the financial information for OMX for the period January 1, 2007 through December 31, 2007 is also included in the unaudited

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pro forma condensed combined statement of income for the year ended December 31, 2007 in this Form 8-K/A. In addition, the financial information for OMX for the period January 1, 2008 through February 26, 2008 is also included in the unaudited pro forma condensed combined statement of income for the three months ended March 31, 2008 in this Form 8-K/A. Since balance sheet financial information for OMX is included in NASDAQ OMX’s historical balance sheet at March 31, 2008, separate pro forma balance sheet data for OMX is not presented. All required historical financial statements of PHLX and OMX are hereby incorporated by reference in this Form 8-K/A and shall be deemed filed for purposes of the Securities Exchange Act of 1934, as amended. The pro forma financial statements of the combined entity are intended to be furnished pursuant to Item 9.01(b). Such information, including Exhibit 99.5 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, except as shall be expressly set forth by specific reference in such filing.

Throughout this Form 8-K/A, including the exhibits hereto, unless otherwise specified:

EXPLANATORY NOTE

This Current Report on Form 8-K/A, or Form 8-K/A, dated May 2, 2008, amends the Current Report on Form 8-K filed by The NASDAQ OMX Group, Inc. on March 3, 2008, concerning (i) the business combination of The Nasdaq Stock Market, Inc. with OMX AB (publ), and (ii) the acquisition of a 33 ¹/3% interest in the Dubai International Financial Exchange, or DIFX, each occurring on February 27, 2008 (collectively, the Transactions). This Form 8-K/A includes the required historical financial information of OMX and the required pro forma financial statements of the combined entity, each as required by Item 9.01 of Form 8-K. All required historical financial statements of OMX are hereby incorporated by reference in this Form 8-K/A and shall be deemed filed for purposes of the Securities Exchange Act of 1934, as amended. The pro forma financial statements of the combined entity are intended to be furnished pursuant to Item 9.01(b). Such information, including Exhibit 99.3 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, except as shall be expressly set forth by specific reference in such filing.

Throughout this Form 8-K/A, including the exhibits hereto, unless otherwise specified:

Explanatory Note

This Quarterly Report on Form 10-Q/A (“Form 10-Q/A”) is being filed as Amendment No. 1 to the Registrant’s Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2005. This Form 10-Q/A is filed with the U.S. Securities and Exchange Commission for the purpose of providing corrected exhibits 31.1 and 31.2. This report speaks as of the original filing date and, except as indicated, has not been updated to reflect events occurring subsequent to the original filing date.

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The Nasdaq Stock Market, Inc.