What is the main purpose of this 8-K filing?

The primary purpose of this 8-K filing is to furnish financial statements from CME Group's Q3 2007 10-Q filing in XBRL (Extensible Business Reporting Language) format, specifically for testing the XBRL format and technology.

Should I make investment decisions based on the financial data in this 8-K?

No, investors are strongly advised not to rely on the XBRL-formatted financial data in this 8-K for making investment decisions. The filing explicitly states that this data is unaudited and provided for testing purposes only. Investors should continue to rely on the official, previously filed versions of financial statements.

Does this 8-K contain any new financial results or material business updates for CME Group?

No, this 8-K filing does not present new financial results or disclose any new material events. It merely re-formats and re-furnishes historical financial data from a prior 10-Q filing (Q3 2007) into XBRL for technological testing.

What is XBRL and why is CME Group testing it?

XBRL (Extensible Business Reporting Language) is a global standard for digitizing business reports. CME Group is testing it as part of an effort to adopt and evaluate new technologies for financial reporting, as mandated or encouraged by regulatory bodies.

CME 8-K SEC Disclosure — May 30, 2008

Summary

CME Group Inc. (CME) filed a Current Report (8-K) on May 29, 2008, primarily to furnish XBRL-formatted financial statements from its Q3 2007 10-Q filing. This report serves as a test for XBRL technology and is not intended to be a primary source for investment decisions. Investors are advised to rely on the officially filed financial statements and not the XBRL data for making investment decisions, as the XBRL financial information is unaudited and presented for format and technology testing purposes only. This filing does not contain any new material events or financial updates beyond the previous 10-Q filing. The company explicitly states that the information furnished is not considered "filed" under Section 18 of the Securities Exchange Act of 1934 and will not be incorporated by reference into other SEC filings. Therefore, investors should not base their investment decisions on this particular 8-K filing.

Key Highlights

1CME Group Inc. filed an 8-K on May 29, 2008, to furnish XBRL-formatted financial data.
2The furnished financial statements are from the Q3 2007 10-Q filing, originally filed on November 8, 2007.
3This filing is explicitly for testing XBRL format and technology.
4Investors are cautioned that the XBRL financial data is unaudited and should not be relied upon for investment decisions.
5The information in this 8-K is not considered "filed" for purposes of Section 18 of the Securities Exchange Act of 1934.
6This filing does not incorporate new financial information or material events beyond the previously filed 10-Q.

CME GROUP INC. 8-K Report, Corporate Update (May 30, 2008)

Summary

Key Highlights

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