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): August 28, 2025

ISABELLA BANK CORPORATION

(Exact name of registrant as specified in its charter)

Michigan

000-18415

38-2830092

(State or other jurisdiction
of incorporation)

(Commission
File Number)

(IRS Employer
Identification No.)

401 North Main Street

Mt. Pleasant

Michigan

48858-1649

(Address of principal executive offices)

(Zip Code)

Registrant’s telephone number, including area code: (989) 772-9471

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 l4a-12 under the Exchange Act (17 CFR 240.l4a-l2)


☐			Pre-commencement communications pursuant to Rule l4d-2(b) under the Exchange Act (17 CFR 240.l4d-2(b))


☐			Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.l3e-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 per share	ISBA	The Nasdaq Stock Market LLC

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 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On August 28, 2025, Isabella Bank Corporation (the "Corporation") informed Mr. William M. Schaefer, Chief Financial Officer ("CFO"), of his termination of employment, effective immediately. Mr. Schaefer's termination did not relate to any disagreement on matters related to the Corporation's operations, policies or practices or any other matter, and Mr. Schaefer was not aware of any deficiencies in financial or operating controls at the time of his termination.

Effective upon Mr. Schaefer's termination, Neil McDonnell, the President of the Corporation's wholly-owned subsidiary, Isabella Bank (the "Bank"), will serve as interim CFO of the Corporation, while a national search is conducted to identify a permanent CFO. Mr. McDonnell, who will continue to serve as President of the Bank, previously served as the Corporation's CFO for six years before being appointed President of the Bank in January 2024.

SIGNATURES

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.

ISABELLA BANK CORPORATION

Dated:

August 28, 2025

By:

/s/ Jerome E. Schwind

Jerome E. Schwind, President and Chief Executive Officer

ISABELLA BANK CORP 8-K