UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 12b-25

SEC File Number: 001-40946

NOTIFICATION OF LATE FILING

(Check one):	☐  Form 10-K     ☐  Form 20-F     ☐  Form 11-K     ☒  Form 10-Q ☐  Form 10-D     ☐  Form N-CEN     ☐  Form N-CSR
	For Period Ended: September 30, 2021
	☐  Transition Report on Form 10-K
	☐  Transition Report on Form 20-F
	☐  Transition Report on Form 11-K
	☐  Transition Report on Form 10-Q
	For the Transition Period Ended:

Read Instructions (on back page) Before Preparing Form. Please Print or Type.

Nothing in this form shall be construed to imply that the Commission has verified any information contained herein.

If the notification relates to a portion of the filing checked above, identify the Item(s) to which the notification relates:

PART I — REGISTRANT INFORMATION

M3-Brigade Acquisition III Corp.

Full Name of Registrant

Former Name if Applicable

1700 Broadway, 19th Floor

Address of Principal Executive Office (Street and Number)

New York, NY 10019

City, State and Zip Code

PART II — RULES 12b-25(b) AND (c)

If the subject report could not be filed without unreasonable effort or expense and the registrant seeks relief pursuant to Rule 12b-25(b), the following should be completed. (Check box if appropriate)

☒	(a)	The reason described in reasonable detail in Part III of this form could not be eliminated without unreasonable effort or expense
	(b)	The subject annual report, semi-annual report, transition report on Form 10-K, Form 20-F, Form 11-K, Form N-CEN or Form N-CSR, or portion thereof, will be filed on or before the fifteenth calendar day following the prescribed due date; or the subject quarterly report or transition report on Form 10-Q or subject distribution report on Form 10-D, or portion thereof, will be filed on or before the fifth calendar day following the prescribed due date; and
	(c)	The accountant’s statement or other exhibit required by Rule 12b-25(c) has been attached if applicable.

PART III — NARRATIVE

State below in reasonable detail why Forms 10-K, 20-F, 11-K, 10-Q, 10-D, N-CEN, N-CSR, or the transition report or portion thereof, could not be filed within the prescribed time period.

M3-Brigade Acquisition III Corp. (the “Company”) is unable to file, without unreasonable effort and expense, its Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2021 (the “Form 10-Q”) on or prior to the prescribed due date of December 6, 2021 due to a delay in processing of the filing which was outside of the Company’s control. These issues have since been remedied and the Company has already filed its Form 10-Q.

PART IV — OTHER INFORMATION

(1)	Name and telephone number of person to contact in regard to this notification
	Charles Garner	212	202-2212
	(Name)	(Area Code)	(Telephone Number)
(2)	Have all other periodic reports required under Section 13 or 15(d) of the Securities Exchange Act of 1934 or Section 30 of the Investment Company Act of 1940 during the preceding 12 months or for such shorter period that the registrant was required to file such report(s) been filed? If answer is no, identify report(s).    Yes  ☒    No  ☐
(3)	Is it anticipated that any significant change in results of operations from the corresponding period for the last fiscal year will be reflected by the earnings statements to be included in the subject report or portion thereof?    Yes  ☐    No  ☒
	If so, attach an explanation of the anticipated change, both narratively and quantitatively, and, if appropriate, state the reasons why a reasonable estimate of the results cannot be made.

M3-Brigade Acquisition III Corp.

(Name of Registrant as Specified in Charter)

has caused this notification to be signed on its behalf by the undersigned hereunto duly authorized.

Date	12/7/2021	By	/s/ Mohsin Y. Meghji
			Mohsin Y. Meghji
			Executive Chairman of the Board of Directors

INSTRUCTION: The form may be signed by an executive officer of the registrant or by any other duly authorized representative. The name and title of the person signing the form shall be typed or printed beneath the signature. If the statement is signed on behalf of the registrant by an authorized representative (other than an executive officer), evidence of the representative’s authority to sign on behalf of the registrant shall be filed with the form.

ATTENTION

Intentional misstatements or omissions of fact constitute Federal Criminal Violations (See 18 U.S.C. 1001).