GREAT SOUTHERN BANCORP, INC.

We maintain a system of disclosure controls and procedures (as defined in Rule 13(a)-15(e) under the Securities Exchange Act of 1934 (the “Exchange Act”)) that is designed to provide reasonable assurance that information required to be disclosed by us in the reports that we file under the Exchange Act is recorded, processed, summarized and reported accurately and within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including our principal executive officer and principal financial officer, as appropriate. An evaluation of our disclosure controls and procedures was carried out as of September 30, 2025, under the supervision and with the participation of our principal executive officer, principal financial officer and several other members of our senior management. Our principal executive officer and principal financial officer concluded that, as of September 30, 2025, our disclosure controls and procedures were effective in ensuring that the information we are required to disclose in the reports we file or submit under the Act is (i) accumulated and communicated to our management (including the principal executive officer and principal financial officer) to allow timely decisions regarding required disclosure, and (ii) recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms.

There were no changes in our internal control over financial reporting (as defined in Rule 13a-15(f) under the Exchange Act) that occurred during the quarter ended September 30, 2025, that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

We do not expect that our internal control over financial reporting will prevent all errors and all fraud. A control procedure, no matter how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control procedure are met. Because of the inherent limitations in all control procedures, no evaluation of controls can provide absolute assurance that all control issues and instances of fraud, if any, within the Company have been detected. These inherent limitations include the realities that judgments in decision-making can be faulty, and that breakdowns in controls or procedures can occur because of simple error or mistake. Additionally, controls can be circumvented by the individual acts of some persons, by collusion of two or more people, or by management override of the control. The design of any control procedure also is based in part upon certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions; over time, controls may become inadequate because of changes in conditions, or the degree of compliance with the policies or procedures may deteriorate. Because of the inherent limitations in a cost-effective control procedure, misstatements due to error or fraud may occur and not be detected.

PART II. OTHER INFORMATION

In the normal course of business, the Company and its subsidiaries are subject to pending and threatened legal actions, some of which seek substantial relief or damages. While the ultimate outcome of such legal proceedings cannot be predicted with certainty, after reviewing pending and threatened litigation with counsel, management believes at this time that the outcome of such litigation will not have a material adverse effect on the Company’s business, financial condition or results of operations.

One litigation matter in which the Bank is defendant was previously set for trial in the third quarter of 2025. The trial was postponed and has not yet been rescheduled. The plaintiffs allege a breach of fiduciary duty in this matter. At this stage of the proceeding it is not possible to predict the outcome. However, the Bank believes it will prevail in this matter, and further believes that any loss should be indemnified, in whole or in part, or shared by others.