DTF Tax Free Income 2028 Term Fund : Notice of Joint Annual Meeting of Shareholders

JOINT PROXY STATEMENT

The board of directors (the "Board") of each of DNP Select Income Fund Inc. ("DNP"), Duff & Phelps Utility and Infrastructure Fund Inc. ("DPG") and DTF Tax-Free Income 2028 Term Fund Inc. ("DTF" and, together with DNP and DPG, the "Funds") is soliciting proxies from the shareholders of each Fund for use at the joint annual meeting of shareholders to be held on Monday, March 6, 2023 and at any adjournment or postponement of that meeting. A proxy may be revoked at any time before it is voted, either by voting at the meeting or by written notice to the applicable Fund or delivery of a later-dated proxy.

The meeting is scheduled as a joint meeting of the respective shareholders of the Funds because the shareholders of each Fund are expected to consider and vote on similar matters. The Board has determined that the use of a joint proxy statement for the meeting is in the best interest of the shareholders of each Fund. In the event that any shareholder of a Fund virtually present at the meeting objects to the holding of a joint meeting, raises a reasonable basis for the objection, and moves for an adjournment of such Fund's meeting to a time immediately after the meeting, so that such Fund's meeting may be held separately, the persons named as proxies will vote in favor of such adjournment. Shareholders of each Fund will vote separately on each of the proposals relating to their respective Fund, and an unfavorable vote on a proposal by the shareholders of one Fund will not affect the implementation by the other Fund of such proposal if the shareholders of such other Fund approve the proposal.

Summary of Proposals to Be Voted Upon

Shareholders of record of each Fund at the close of business on December 9, 2022 are entitled to notice of and to participate in the meeting. On the record date: DNP had 354,854,867 shares of common stock outstanding and 2,070 shares of preferred stock outstanding, DPG had 38,115,078 shares of common stock outstanding and 1,600,000 shares of preferred stock outstanding and DTF had 7,029,567 shares of common stock outstanding and 400 shares of preferred stock outstanding. Each share of common stock outstanding on the record date entitles the holder thereof to one vote for each director being elected by the common stock (with no cumulative voting permitted) and to one vote on each other matter. Each share of preferred stock outstanding on the record date entitles the holder thereof to one vote for each director being elected by the preferred stock (with no cumulative voting permitted) and to one vote on each other matter.

This proxy statement is first being mailed on or about January 13, 2023. The Funds will bear the cost of the annual meeting and this proxy solicitation. Total costs for the annual meeting and proxy solicitation, including

1

printing and mailing proxy materials, are estimated at $260,000, and will be charged to the respective Funds based on their proportion of shareholder accounts except where another alternative allocation methodology is deemed more appropriate.

1. ELECTION OF DIRECTORS

The Board of each Fund is responsible for the overall management and operations of that Fund. As of the date of this joint proxy statement, the Board of each Fund is comprised of five directors. Directors of each Fund are divided into three classes and are elected to serve staggered three-year terms.

The persons named in the enclosed proxy intend to vote in favor of the election of the persons named below (unless otherwise instructed). Each of the nominees has consented to serve as a director of the Funds, if elected. In case any of the nominees should become unavailable for election for any unforeseen reason, the persons designated in the proxy will have the right to vote for a substitute.

Election of DNP Director (Proposal 1a. and 1b.)

At the meeting, holders of DNP common stock are entitled to elect one director for a term ending in 2026 (Ms. Cusack is the nominee for that term) as well as one director for a term ending in 2025 (Mr. Vitale is the nominee for that term) and the holders of DNP preferred stock are entitled to elect one director for a term ending in 2026 (Ms. McNamara is the nominee for that term). If elected, Ms. Cusack and Ms. McNamara will serve until the annual meeting of shareholders in 2026 and until their respective successors are elected and qualified, and Mr. Vitale will retire following the annual meeting of shareholders in 2025, pursuant to the Funds' director retirement policy. A plurality of votes cast at the meeting by the holders of DNP common stock as to the directors representing the common stock is necessary to elect those directors. A plurality of votes cast at the meeting by the holders of DNP preferred stock as to the director representing the preferred stock is necessary to elect that director. Abstentions and broker-non-votes will be counted for purposes of determining whether a quorum is present at the meeting, but will not affect the determination of whether a director candidate has received a plurality of votes cast.

Election of DPG Director (Proposal 1c. and 1.d.)

At the meeting, holders of DPG common and preferred stock, voting as a single class, are entitled to elect one director for a term ending in 2026 (Ms. Cusack is the nominee for that term) as well as one director for a term ending in 2025 (Mr. Vitale is the nominee for that term) and the holders of DPG preferred stock are entitled to elect one director for a term ending in 2026 (Ms. McNamara is the nominee for that term). If elected, Ms. Cusack and Ms. McNamara will serve until the annual meeting of shareholders in 2026 and until their respective successors are elected and qualified, and Mr. Vitale will retire following the annual meeting of shareholders in 2025, pursuant to the Funds' director retirement policy. A plurality of votes cast at the meeting by the holders of DPG common and preferred stock, voting as a single class, as to the directors representing the common and preferred stock is necessary to elect those directors. A plurality of votes cast at the meeting by the holders of DPG preferred stock as to the director representing the preferred stock is necessary to elect that director. Abstentions and broker-non-votes will be counted for purposes of determining whether a quorum is present at the meeting, but will not affect the determination of whether a director candidate has received a plurality of votes cast.

2

Election of DTF Directors (Proposal 1e. and 1f.)

At the meeting, holders of DTF common and preferred stock, voting as a single class, are entitled to elect one director for a term ending in 2026 (Ms. Cusack is the nominee for that term) as well as one director for a term ending in 2025 (Mr. Vitale is the nominee for that term) and the holders of DTF preferred stock are entitled to elect one director for a term ending in 2026 (Ms. McNamara is the nominee for that term). If elected, Ms. Cusack and Ms. McNamara will serve until the annual meeting of shareholders in 2026 and until their respective successors are elected and qualified, and Mr. Vitale will retire following the annual meeting of shareholders in 2025, pursuant to the Funds' director retirement policy. A plurality of votes cast at the meeting by the holders of DTF common and preferred stock, voting as a single class, as to the directors representing the common and preferred stock is necessary to elect those directors. A plurality of votes cast at the meeting by the holders of DTF preferred stock as to the director representing the preferred stock is necessary to elect that director. Abstentions and broker-non-votes will be counted for purposes of determining whether a quorum is present at the meeting, but will not affect the determination of whether a director candidate has received a plurality of votes cast.

Biographical Information about Nominees and Continuing Directors

Set forth in the table below are the names and certain biographical information about the nominees for the position of director and the continuing directors of the Funds. Except as noted:

• all of the directors are elected to the DNP Board by the holders of DNP common stock voting as a separate class;
• all of the directors are elected to the DPG Board by the holders of DPG common and preferred stock voting as a single class; and
• all of the directors are elected to the DTF Board by the holders of DTF common and preferred stock voting as a single class;.

All of the directors of the Funds (including the director nominees) are classified as independent directors because none of them are "interested persons" of the Funds, as defined in the Investment Company Act of 1940 (the "1940 Act"). Each of the current directors formerly served on the Board of Directors of Duff & Phelps Utility and Corporate Bond Trust Inc. until its merger into DNP in March 2021. The term "Fund Complex" refers to the Funds and all other investment companies advised by affiliates of Virtus Investment Partners, Inc. ("Virtus"), the Adviser's parent company. The address for all directors is c/o Duff & Phelps Investment Management Co., 200 South Wacker Drive, Suite 500, Chicago, Illinois 60606.

3