Amendment: SEC Form SCHEDULE 13D/A filed by Telephone and Data Systems Inc.

The principal business address of the Voting Trust is c/o Walter C. D. Carlson, Telephone and Data Systems, Inc., 30 North LaSalle Street, Suite 4000, Chicago, Illinois 60602. The information required under paragraph (b) with respect to the Trustees is set forth in Appendix A hereto, and incorporated herein by reference.

The Voting Trust holds TDS Common Shares and TDS Series A Common Shares and was created to facilitate long-standing relationships among the trust's certificate holders. Under the terms of the Voting Trust, the Trustees hold and vote the TDS Series A Common Shares and TDS Common Shares held in the trust. The information required under paragraph (c) with respect to the Trustees is set forth in Appendix A hereto, and incorporated herein by reference.

During the last five years, neither the Voting Trust nor any of the Trustees identified in Appendix A hereto has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

During the last five years, neither the Voting Trust nor any of the Trustees thereof identified in Appendix A hereto was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction, and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

The Voting Trust is organized under Delaware law. The information required under paragraph (f) with respect to the Trustees is set forth in Appendix A hereto, and incorporated herein by reference.

The information contained in Item 4 below is incorporated herein by reference.

On May 7, 2026, the Issuer delivered to the board of directors (the "Array Board") of Array Digital Infrastructure, Inc. (formerly known as United States Cellular Corporation), a Delaware corporation ("Array"), a letter setting forth a non-binding proposal to acquire all of the outstanding Common Shares, par value $1.00 per share, of Array ("Array Common Shares") that are not owned by the Issuer (the "Proposal"). A copy of the Proposal is filed herewith as Exhibit 2, and the information set forth in the Proposal is incorporated herein by reference. In connection with the Proposal, the Issuer expects to engage in discussions with the Array Board (including any Special Committee formed by the Array Board) or their representatives. The Proposal may result in one or more of the transactions, events or actions specified in clauses (a) through (j) of Item 4 of Schedule 13D. No assurances can be given that the transaction contemplated by the Proposal or any other potential transaction involving the Issuer and Array will be consummated, or if a transaction is undertaken, as to its terms or timing. The Trustees do not intend to update this Schedule 13D regarding the Proposal until a definitive agreement has been reached, or an update is otherwise required under applicable law. The Trustees intend to maintain the ability to keep or dispose of the voting control of the Issuer. If and to the extent that Array remains a publicly-traded company, the Trustees intend that the Issuer maintain the ability to keep or dispose of the voting control of Array. The Trustees also retain the right to change their intent, to acquire additional securities from time to time or to dispose of all or part of the securities beneficially owned by the Voting Trust in any manner permitted by the terms of the Voting Trust and/or applicable law.

As of the end of the trading day on March 31, 2026, pursuant to Rule 13d-3(d)(1)(i), the Voting Trust and each of the Trustees may be deemed to beneficially own an aggregate of 6,304,105 TDS Common Shares, and 7,213,594 TDS Series A Common Shares held by the Voting Trust that are convertible into 7,213,594 TDS Common Shares. See Appendix B hereto for additional TDS Common Shares beneficially owned by each of the Trustees.

The following information is provided with respect to the shares held by the Voting Trust. See Appendix B hereto for information with respect to other shares beneficially owned by each of the Trustees. (i) Sole Power to Vote or Direct the Vote: None. (ii) Shared Power to Vote or Direct the Vote: The Voting Trust is the direct beneficial owner of TDS Common Shares and TDS Series A Common Shares that are convertible on a share-for-share basis into TDS Common Shares. The Voting Trust may be deemed to hold approximately 95.6% of the outstanding TDS Series A Common Shares and approximately 5.9% of the outstanding TDS Common Shares for a combined total of approximately 11.9% of the Issuer's outstanding classes of capital stock and approximately 56.8% of the voting power on an aggregate basis. The holders of TDS Common Shares are entitled to elect four of the current twelve directors of the Issuer. The Trustees hold 5.9% of the voting power in the election of such four directors. In addition, the holders of TDS Common Shares have votes per share that are subject to adjustment in matters other than the election of directors. The TDS Common Shares held by the Voting Trust represent approximately 2.6% of the combined voting power in matters other than the election of directors. The holders of TDS Series A Common Shares are entitled to elect eight of the current twelve directors of the Issuer. The reporting persons hold 95.6% of the voting power in the election of such eight directors. The TDS Series A Common Shares also have ten votes per share in matters other than the election of directors. The TDS Series A Common Shares held by the Voting Trust represent approximately 54.2% of the total combined voting power in matters other than the election of directors. As a result of the foregoing, the Voting Trust elects a majority of the directors and directs a majority of the combined voting power of the Issuer in matters other than the election of directors. (iii) Sole Power to Dispose or Direct the Disposition: None. (iv) Shared Power to Dispose or Direct the Disposition: The information contained in Item 5(b)(ii) above is incorporated herein by reference.

Except as disclosed below, no transactions were effected during the past sixty days in TDS Common Shares or TDS Series A Common Shares by the Voting Trust or the Trustees. (i) On March 23, 2026, Prudence E. Carlson sold 5,811 Common Shares pursuant to a Rule 10b5-1 Plan. (ii) Transactions as a result of participation in TDS' Automatic Dividend Reinvestment Plans (under which the Voting Trust acquired 967 Series A Common Shares and 716 Common Shares at a per share price equal to $40.35 during the past 60 days).

Except as disclosed below, no other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, TDS Common Shares or TDS Series A Common Shares beneficially owned by the Voting Trust. Under the terms of the Voting Trust, except to the extent necessary to pay Voting Trust expenses, all cash dividends are distributed to the beneficiaries of the Voting Trust. The Trustees do not have the power to sell any TDS Common Shares or TDS Series A Common Shares deposited by a certificate holder without the consent of such certificate holder.

Not applicable.

The Voting Trust was created to facilitate long-standing relationships among the trust's certificate holders. Under the terms of the Voting Trust, the Trustees hold and vote the TDS Series A Common Shares and TDS Common Shares held in the trust. The information contained in Item 5(b)(ii) above is incorporated herein by reference.

Exhibit 1: Joint Filing Agreement and Signatures Exhibit 2: Letter, dated May 7, 2026, from the Issuer to the Array Board Appendix A Appendix B