Material Agreement (Form 8-K)

Item 1.01 Entry into a Material Definitive Agreement.

As previously disclosed on June 18, 2025, M3-Brigade Acquisition V Corp. (the "Company") issued a convertible promissory note (the "Note") to M17 Sponsor, LLC (the "Sponsor"), the Company's sponsor, pursuant to which the Company can borrow up to an aggregate principal amount of $2,500,000 from the Sponsor, after which the Company borrowed $500,000 under the note on June 18, 2025. Unless otherwise defined herein, capitalized terms used in this Current Report on Form 8-K shall have the same meaning set forth in the Note.

On July 16, 2025, the Company and the Sponsor entered into the First Amendment to the Note (the "Note Amendment"), solely to correct a scrivener's error regarding the Sponsor's option to convert up to $1,500,000 of the outstanding unpaid principal balance under the Note into Private Placement Warrants at a purchase price of $1.50 per Private Placement Warrant. Pursuant to the Note Amendment, the purchase price per Private Placement Warrant was corrected to reflect a purchase price of $1.00 per Private Placement Warrant upon conversion under the Note. All other terms of the Note remain unchanged.

The foregoing description of the Note Amendment is subject to and qualified in its entirety by reference to the full text of the Note Amendment, a copy of which is included as Exhibit 10.1 hereto, and the terms of which are incorporated herein by reference.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under and Off-Balance Sheet Arrangement of a Registrant.

The information set forth in Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 2.03.