TELEPHONE & DATA SYSTEMS INC /DE/

Additional Required Information

Controls and Procedures

Evaluation of Disclosure Controls and Procedures

TDS maintains disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the Exchange Act)) that are designed to ensure that information required to be disclosed in its reports filed or submitted under the Exchange Act is processed, recorded, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to TDS’ management, including its principal executive officer and principal financial officer, as appropriate, to allow for timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives.

As required by SEC Rules 13a-15(b), TDS carried out an evaluation, under the supervision and with the participation of management, including its principal executive officer and principal financial officer, of the effectiveness of the design and operation of TDS’ disclosure controls and procedures as of the end of the period covered by this Quarterly Report. Based on this evaluation, TDS’ principal executive officer and principal financial officer concluded that TDS' disclosure controls and procedures were effective as of September 30, 2025, at the reasonable assurance level.

Changes in Internal Control Over Financial Reporting

During the three months ended September 30, 2025, TDS evaluated the impact of the sale of the Array wireless operations on its control framework, which resulted in the removal, addition, and redesign of certain controls. Except for the changes related to the sale of the Array wireless operations, there were no other changes in internal controls over financial reporting that have occurred during the three months ended September 30, 2025, that have materially affected, or are reasonably likely to materially affect, TDS' internal control over financial reporting.