ISABELLA BANK CORP 10-Q

Item 5. Other Information. Securities Trading Plans of Executive Officers During the fiscal quarter ended June 30, 2025, none of the Corporation’s directors or officers adopted, modified or terminated a “Rule 10b5-1 trading arrangement” or a “non-Rule 10b5-1 trading arrangement,” in each case as defined in Item 408 of Regulation S-K. 59 Table of Contents Item 6. Exhibits. (a) Exhibits Exhibit Number Exhibits 3.1 Amended Articles of Incorporation (1) 3.2 Amendment to the Articles of Incorporation (2) 3.3 Amendment to the Articles of Incorporation (3) 3.4 Amendment to the Articles of Incorporation (4) 3.5 Amendment to the Articles of Incorporation (7) 3.6 Amended Bylaws (5) 3.7 Amendment to Bylaws (6) 3.8 Amendment to Bylaws (8) 3.9 Amendment to Bylaws (9) 10.1 Award Agreeme nt for Jerome Schwind (10) 10.2 Award Agreement for Neil McDonnell (10) 10.3 Award Agreement for William Sc haefer (10) 10.4 Isabella Bank Corporation Amended and Restated Supplemental Executive Retirement Plan (10) 31.1 Certification pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 by the Principal Executive Officer 31.2 Certification pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 by the Principal Financial Officer 32 Section 1350 Certification of Principal Executive Officer and Principal Financial Officer 101.1** 101.INS (Inline XBRL Instance Document) 101.SCH (Inline XBRL Taxonomy Extension Schema Document) 101.CAL (Inline XBRL Calculation Linkbase Document) 101.LAB (Inline XBRL Taxonomy Label Linkbase Document) 101.DEF (Inline XBRL Taxonomy Linkbase Document) 101.PRE (Inline XBRL Taxonomy Presentation Linkbase Document) 104 Cover Page Interactive Data File * Management Contract or Compensatory Plan or Arrangement. ** In accordance with Rule 406T of Regulations S-T, the XBRL related information shall not be deemed to be “filed” for purposes of Section 18 of the Exchange Act, or otherwise subject to the liability of that section, and shall not be part of any registration statement or other document filed under the Securities Act or the Exchange Act, except as shall be expressly set forth by specific reference in such filing. (1) Previously filed as an Exhibit to the Isabella Bank Corporation Form 10-K, filed March 12, 1991, and incorporated herein by reference (2) Previously filed as an Exhibit to the Isabella Bank Corporation Form 10-K, filed March 26, 1994, and incorporated herein by reference. (3) Previously filed as an Exhibit to Isabella Bank Corporation Form 10-K, filed March 22, 2000, and incorporated herein by reference. (4) Previously filed as an Exhibit to Isabella Bank Corporation Form 10-K, filed March 27, 2001, and incorporated herein by reference. (5) Previously filed as an Exhibit to Isabella Bank Corporation Form 10-K, filed March 16, 2005, and incorporated herein by reference. (6) Previously filed as an Exhibit to Isabella Bank Corporation Form 8-K, filed November 22, 2006, and incorporated herein by reference. (7) Previously filed as an Exhibit to Isabella Bank Corporation Form 8-K, filed May 16, 2008, and incorporated herein by reference. (8) Previously filed as an Exhibit to Isabella Bank Corporation Form 8-K, filed August 28, 2009, and incorporated herein by reference. (9) Previously filed as an Exhibit to Isabella Bank Corporation Form 8-K, filed December 23, 2009, and incorporated herein by reference. (10) Previously filed as an Exhibit to Isabella Bank Corporation Form 8-K, filed April 7, 2025, and incorporated herein by reference. 60 Table of Contents 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 thereunto duly authorized. Isabella Bank Corporation Date: August 11, 2025 /s/ Jerome E. Schwind Jerome E. Schwind President and Chief Executive Officer (Principal Executive Officer) Date: August 11, 2025 /s/ William M. Schaefer William M. Schaefer Chief Financial Officer (Principal Financial Officer) 61