[8-K] MESA AIR GROUP INC Reports Material Event

Rhea-AI Filing Summary

Mesa Air Group is changing its fiscal year end from September 30 to December 31, effective for the fiscal year beginning January 1, 2025 and ending December 31, 2025. To cover the gap created by this calendar-year shift, Mesa will file a transition report, a Form 10-KT, for the period October 1, 2024 through December 31, 2024, with a required filing date no later than December 29, 2025. The change was reported on September 29, 2025 and signed by Brian S. Gillman, Executive Vice President and General Counsel.

Positive

• Aligns reporting with calendar year, simplifying comparability with peers and fiscal planning
• Clear transition timeline with a specified 10-KT filing date of December 29, 2025

Negative

• Requires a transition 10-KT for Oct 1–Dec 31, 2024, adding a one-time reporting and audit burden
• Potential timing complexity for quarterly and annual metrics during the calendar change in 2025

Insights

Corporate Finance Analyst

Shifting year-end aligns reporting with calendar year and requires a transition 10-KT.

The company is moving its fiscal year end to December 31, which normalizes future reporting to calendar years beginning January 1, 2025. This creates a short transition period (Oct 1–Dec 31, 2024) that must be reported on a 10-KT, due by December 29, 2025. The mechanics are administrative but require careful timing of disclosures and audited financials for the transition period.

Key dependencies include completing any required audits or review for the transition period and aligning internal reporting calendars by 2025. Investors should note the one-time reporting step and expect the regular annual cadence to follow calendar-year filings thereafter.

MESA AIR GROUP INC NASDAQ false 0000810332 --09-30 0000810332 2025-09-24 2025-09-24

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 24, 2025

Mesa Air Group, Inc.

(Exact name of Registrant as Specified in Its Charter)

Nevada		001-38626		85-0302351
(State or Other Jurisdiction of Incorporation)		(Commission File Number)		(IRS Employer Identification No.)

410 North 44th Street, Suite 700
Phoenix, Arizona		85008
(Address of Principal Executive Offices)		(Zip Code)

Registrant’s Telephone Number, Including Area Code: (602) 685-4000

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, no par value		MESA		Nasdaq Capital Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.03. Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On September 24, 2025, the Board of Directors of Mesa Air Group, Inc. (the “Company”) approved a change in the Company’s fiscal year-end, moving from September 30 to December 31 of each year, effective for the fiscal year beginning on January 1, 2025 and ending on December 31, 2025.

The Company will file a Quarterly Report on Form 10-Q on or about November 14, 2025 for the three and nine months ending September 30, 2025 and will file a Transition Report on Form 10-KT no later than December 29, 2025 for the transition period from October 1, 2024 through December 31, 2024.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

				Mesa Air Group, Inc.
Date: September 29, 2025				By:		/s/ Brian S. Gillman
						Name: Brian S. Gillman
						Title: Executive Vice President and General Counsel

FAQ

What change did MESA (NASDAQ:MESA) report?

Mesa disclosed it is changing its fiscal year end from September 30 to December 31, effective for the fiscal year beginning January 1, 2025.

When must MESA file the transition 10-KT?

Mesa must file a Form 10-KT for the transition period no later than December 29, 2025 covering October 1–December 31, 2024.

What period does the 10-KT cover?

The transition report covers the period from October 1, 2024 through December 31, 2024.

Who signed the 8-K reporting this change?

The filing was signed by Brian S. Gillman, Executive Vice President and General Counsel, on September 29, 2025.

Will the fiscal-year change affect future reporting cadence?

Yes. After the transition, annual reports and periodic filings will follow the calendar year, with fiscal years ending on December 31 starting in 2025.