Exhibit 99.1

DESCRIPTION OF COMMON STOCK

Listing

Our outstanding shares of common stock are listed on the New York Stock Exchange under the symbol “D”. Any additional common stock we issue will also be listed on the New York Stock Exchange.

Dividends

Common shareholders may receive dividends when declared by our board of directors. Dividends may be paid in cash, stock or other form. In certain cases, common shareholders may not receive dividends until we have satisfied our obligations to any preferred shareholders. Under certain circumstances, our indentures may also restrict our ability to pay cash dividends.

Authorized But Unissued Shares

Our authorized but unissued shares of common stock will be available for future issuance without shareholder approval. These additional shares may be utilized for a variety of corporate purposes, including future public offerings to raise additional capital, corporate acquisitions and employee benefit plans. The existence of authorized but unissued shares of common stock and preferred stock could render more difficult or discourage an attempt to obtain control of us by means of a proxy contest, tender offer, merger or otherwise.

Fully Paid

All outstanding shares of common stock are fully paid and non-assessable. Any additional common stock we issue will also be fully paid and non-assessable.

Voting Rights

Each share of common stock is entitled to one vote in the election of directors and other matters. Common shareholders are not entitled to cumulative voting rights.

Other Rights

We will notify common shareholders of any shareholders’ meetings according to applicable law. If we liquidate, dissolve or wind up our business, either voluntarily or not, common shareholders will share equally in the assets remaining after we pay our creditors and preferred shareholders.

Transfer Agent and Registrar

Broadridge Financial Solutions, Inc. serves as transfer agent and registrar for our common stock. You may contact Broadridge at 51 Mercedes Way, Edgewood, New York 11717.

VIRGINIA STOCK CORPORATION ACT AND THE ARTICLES AND THE BYLAWS

General

We are a Virginia corporation subject to the Virginia Stock Corporation Act (the Virginia Act). Provisions of the Virginia Act, in addition to provisions of our Articles of Incorporation (Articles) and Bylaws, address corporate governance issues, including the rights of shareholders. Some of these provisions could hinder management changes while others could have an anti- takeover effect. This anti-takeover effect may, in some circumstances, reduce the control premium that might otherwise be reflected in the value of our common stock. If you are buying our common stock as part of a short-term investment strategy, this might be especially important to you.

We have summarized the key provisions below. You should read the actual provisions of our Articles and Bylaws and the Virginia Act that relate to your individual investment strategy.

Business Combinations

Our Articles require that any merger, share exchange or sale of substantially all of our assets be approved by a majority of the votes entitled to be cast on the matter by each voting group entitled to vote on the matter. Abstentions and broker non-votes will have no effect on the outcome.

Article 14 of the Virginia Act contains several provisions relating to transactions with interested shareholders. Interested shareholders are holders of more than 10% of any class of a corporation’s outstanding voting shares. Transactions between a corporation and an interested shareholder are referred to as affiliated transactions. The Virginia Act requires that material affiliated transactions must be approved by at least two-thirds of the shareholders not including the interested shareholder. Affiliated transactions requiring this two-thirds approval include mergers, share exchanges, material dispositions of corporate assets, dissolution or any reclassification of securities or merger of the corporation with any of its subsidiaries which increases the percentage of voting shares owned by an interested shareholder by more than five percent.

For three years following the time that a shareholder becomes an interested shareholder, a Virginia corporation cannot engage in an affiliated transaction with the interested shareholder without approval of two-thirds of the disinterested voting shares, and majority approval of disinterested directors. A disinterested director is a director who was a director on the date on which an interested shareholder became an interested shareholder or was recommended for election or elected by a majority of the disinterested directors then on the board. After three years, an affiliated transaction must be approved by either two-thirds of disinterested voting shares or a majority of disinterested directors.

The provisions of the Virginia Act relating to affiliated transactions do not apply if a majority of disinterested directors approve the acquisition of shares making a person an interested shareholder.

The Virginia Act permits corporations to opt out of the affiliated transactions provisions. We have not opted out.

The Virginia Act also contains provisions regulating certain control share acquisitions, which are transactions causing the voting strength of any person acquiring beneficial ownership of shares of a public corporation in Virginia to meet or exceed certain threshold voting percentages (20%, 33 ¹ / ₃ %, or 50%). Shares acquired in a control share acquisition have no voting rights unless the voting rights are granted by a majority vote of all outstanding shares other than those held by the acquiring person or any officer or employee-director of the corporation. The acquiring person may require that a special meeting of the shareholders be held to consider the grant of voting rights to the shares acquired in the control share acquisition.

Our Bylaws give us the right to redeem the shares purchased by an acquiring person in a control share acquisition. We can do this if the acquiring person fails to deliver a statement to us listing information required by the Virginia Act or if our shareholders vote not to grant voting rights to the acquiring person.

The Virginia Act permits corporations to opt out of the control share acquisition provisions. We have not opted out.

Directors’ Duties

The standards of conduct for directors of Virginia corporations are listed in Section 13.1-690 of the Virginia Act. Directors must discharge their duties in accordance with their good faith business judgment of the best interests of the corporation. Directors may rely on the advice or acts of others, including officers, employees, attorneys, accountants and board committees if they have a good faith belief in their competence. Directors’ actions are not subject to a reasonableness or prudent person standard. Virginia’s federal and state courts have focused on the process involved with directors’ decision-making and are generally supportive of directors if they have based their decision on an informed process. These elements of Virginia law could make it more difficult to take over a Virginia corporation than corporations in other states.

Board of Directors

Members of our board of directors serve one-year terms and are elected annually. Except when the number of nominees exceeds the number of directors to be elected (a contested election), directors are elected by majority vote.

In the case of a contested election, directors are elected by a plurality vote. Directors may be removed from office for cause if the number of votes cast to remove the director constitutes a majority of the votes entitled to be cast at an election of directors of the voting group by which the director was elected.

Shareholder Proposals and Director Nominations

Our shareholders can submit shareholder proposals and nominate candidates for the Board of Directors if the shareholders follow advance notice procedures described in our Bylaws.

To nominate directors, shareholders must submit a written notice to our corporate secretary at least 60 days before a scheduled meeting. The notice must include the name and address of the shareholder and of the nominee, a description of any arrangements between the shareholder and the nominee, information about the nominee required by the Securities and Exchange Commission, the written consent of the nominee to serve as a director and other information.

Shareholder proposals must be submitted to our corporate secretary at least 90 days before the first anniversary of the date of our last annual meeting. The notice must include a description of the proposal, the reasons for presenting the proposal at the annual meeting, the text of any resolutions to be presented, the shareholder’s name and address and number of shares held and any material interest of the shareholder in the proposal.

Director nominations and shareholder proposals that are late or that do not include all required information may be rejected. This could prevent shareholders from bringing certain matters before an annual or special meeting, including making nominations for directors.

Proxy Access

Our Bylaws permit a shareholder, or a group of up to 20 shareholders, owning 3% or more of our outstanding common stock continuously for at least three years, to nominate and include in our annual meeting proxy materials director candidates to occupy up to two or 20% of our board seats (whichever is greater), provided that such shareholder or group of shareholders satisfies the requirements set forth in the Bylaws.

Meetings of Shareholders

Under our Bylaws, meetings of the shareholders may be called by the chairman of the board, the vice chairman, the president or a majority of our board of directors. Special meetings of shareholders will also be held whenever called by the Corporate Secretary, upon the written request of shareholders owning continuously for a period of at least one year prior to the date of such request more than 25% of all of our outstanding shares of common stock. These provisions could have the effect of delaying until the next annual shareholders’ meeting shareholder actions which are favored by the holders of 25% or less of our outstanding shares of common stock, because such holders would be able to take action as shareholders, such as electing new directors or approving a merger, only at a duly called shareholders’ meeting.

Amendment of Articles

Generally, our Articles may be amended if the votes cast favoring the amendment exceed the votes cast opposing the amendment at a meeting where a quorum is present. Some provisions of the Articles, however, may only be amended or repealed by a majority of the votes entitled to be cast on the matter by each voting group entitled to vote on the matter.

Indemnification

Under our Articles, we indemnify our officers and directors to the fullest extent permitted under Virginia law against all liabilities incurred in connection with their service to us. We have also entered into agreements relating to the advancement of expenses for certain of our directors and officers in advance of a final disposition of proceedings or the making of any determination of eligibility for indemnification pursuant to our Articles.

Limitation of Liability

Our Articles provide that our directors and officers will not be personally liable for monetary damages to us for breaches of their fiduciary duty as directors or officers, unless they violated their duty of loyalty to us or our shareholders, acted in bad faith, knowingly or intentionally violated the law, authorized illegal dividends or redemptions or derived an improper personal benefit from their action as directors or officers. This provision applies only to claims against directors or officers arising out of their role as directors or officers and not in any other capacity. Directors and officers remain liable for violations of the federal securities laws and we retain the right to pursue legal remedies other than monetary damages, such as an injunction or rescission for breach of the officer’s or director’s duty of care.