POWER OF ATTORNEY For EDGAR Administration and Executing Forms 3, 4 and 5 Pursuant to Section 16(a) of the Securities Exchange Act Know all by these presents, that the undersigned hereby constitutes and appoints each of Margaret Austin Wright and Elizabeth Hensen and any duly appointed Corporate Secretary of CME Group, Inc. (the “Company”), with full power of substitution and re-substitution, acting individually, as the undersigned’s true and lawful attorney-in-fact, with full power and authority as hereinafter described on behalf of and in the name, place and stead of the undersigned to: 1. obtain credentials to enable the undersigned to submit and file documents, forms and information required by Section 16(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or any rule or regulation of the U.S. Securities and Exchange Commission (“SEC”) via the Electronic Data Gathering and Retrieval (“EDGAR”) system, including (a) preparing, executing in the undersigned’s name and on the undersigned’s behalf, and submitting to the SEC a Form ID (and any amendments thereto) or any other documents necessary or appropriate to obtain such credentials and legally binding the undersigned for purpose of the Form ID or such other documents; and (b) enrolling the undersigned in EDGAR Next or any successor filing system, 2. act as an account administrator for the undersigned’s EDGAR account, including: (a) appointing, removing and replacing account administrators, technical administrators, account users, and delegated entities; (b) maintaining the security of Filer’s EDGAR account, including modification of access codes; (c) maintaining, modifying and certifying the accuracy of information on the undersigned’s EDGAR account dashboard; and (d) taking any other actions contemplated by Rule 10 of Regulation S-T, 3. cause the Company to accept a delegation of authority from the undersigned’s EDGAR account administrators and authorize the Company’s EDGAR account administrators pursuant to that delegated entity designation to appoint, remove or replace users for the undersigned’s EDGAR account, 4. seek or obtain, as the undersigned’s representative and on the undersigned’s behalf, information on transactions in the Company’s securities from any third party, including brokers, employee benefit plan administrators and trustees, and the undersigned hereby authorizes any such person to release any such information to any attorney-in-fact and further approves and ratifies any such release of information, 5. execute for and on behalf of the undersigned Forms 3, 4 and 5 and amendments thereto relating to the Company in accordance with Section 16(a) of the Exchange Act and the rules thereunder, 6. do and perform any and all acts for, and on behalf of, the undersigned which may be necessary or desirable to prepare, complete and execute any such Form 3, 4 and 5, and any amendments thereto, and timely file such form with the SEC and any other authority as considered necessary or advisable under Section 16(a) of the Exchange Act and the rules thereunder, and
7. take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his/her discretion. The undersigned hereby grants to each such attorney-in-fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as such attorney-in-fact might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact, or his/her substitute or substitutes, shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that each such attorney-in-fact is serving in such capacity at the request of the undersigned. This Power of Attorney does not relieve the undersigned from responsibility for compliance with the undersigned’s obligations under the Exchange Act, including, without limitation, the reporting requirements under Section 16 of the Exchange Act. Neither the Company nor any attorney-in-fact assumes (i) any liability for the undersigned’s responsibility to comply with the requirements of the Exchange Act, (ii) any liability of the undersigned for any failure to comply with such requirements or (iii) any obligation or liability of the undersigned for profit disgorgement under Section 16(b) of the Exchange Act. This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms, 3, 4, and 5 with respect to the undersigned’s holdings of and transactions in securities issued by the Company, unless earlier revoked by the undersigned in a signed writing delivered to the foregoing attorneys-in-fact. IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this 6th day of May 2026. By: /s/ Hilda Harris Piell Name: Hilda Harris Piell
