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March 26, 2021

VIA EDGAR

Securities and Exchange Commission
100 F Street NE
Washington, D.C. 20549

Re: Global Macro Trust (the “Trust”) — Post-Effective Amendment No. 3 to Registration Statement on Form S-1 (Reg. No. 333-229651)

Ladies and Gentlemen:

Accompanying this letter for filing pursuant to the Securities Act of 1933, as amended, is a copy of the Post-Effective Amendment No. 3 to the Registration Statement on Form S-1 relating to an offering by the Trust of units of beneficial interest. The filing reflects changes to the Trust’s Post-Effective Amendment No. 2 to the Registration Statement on Form S-1 (Reg. No. 333-229651) filed on February 12, 2021. Manually executed signature pages and consents have been executed prior to the time of this electronic filing and will be retained by Millburn Ridgefield Corporation, the Trust’s managing owner, for five years. The purpose of this filing is to address Staff comments to Post-Effective Amendment No. 2, to update information in the Prospectus and to include 2020 audited financial information in the Prospectus.

Thank you very much for your attention to this filing. If you have any questions, please do not hesitate to contact me at (312) 853-7557.

Very truly yours,

/s/ James B. Biery

James B. Biery