Exhibit 4.2

DESCRIPTION OF SECURITIES

REGISTERED PURSUANT TO SECTION 12 OF THE

SECURITIES EXCHANGE ACT OF 1934, AS AMENDED

iBio, Inc. (the “Company,” “we,” “us,” and “our”) has one class of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), which is our common stock, par value $0.001 per share (the “common stock”).

General

The following is a description of the material terms of our common stock.  This is a summary only and does not purport to be complete. It is subject to and qualified in its entirety by reference to our Certificate of Incorporation, as amended (the “Certificate of Incorporation”), and our Second Amended and Restated Bylaws, as may be further amended and restated (the “Bylaws”), each of which are incorporated by reference as an exhibit to our Annual Report on Form 10-K.  We encourage you to read our Certificate of Incorporation, our Bylaws and the applicable provisions of the Delaware General Corporation Law, for additional information.

Description of Common Stock

Authorized Shares of Common Stock.  We currently have authorized 275,000,000 shares of common stock.

Voting.  The holders of our common stock are entitled to one vote per share on all matters to be voted upon by the stockholders and are not entitled to cumulative voting for the election of directors.

Dividends.  Subject to preferences that may be applicable to any then outstanding preferred stock, the holders of common stock are entitled to receive dividends, if any, as may be declared from time to time by our Board of Directors out of legally available funds.

Liquidation. In the event of liquidation, dissolution or winding up of our company, the holders of common stock are entitled to share ratably in all assets remaining after payment of liabilities and the preferences of preferred stockholders.

Rights and Preferences.  The holders of our common stock have no preemptive, conversion or other subscription rights, and there are no redemption or sinking fund provisions applicable to our common stock. The rights, preferences and privileges of the holders of our common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of our preferred stock that is currently outstanding or that we may designate and issue in the future.

Fully Paid and Nonassessable.  All of our issued and outstanding shares of common stock are fully paid and nonassessable.

Potential Anti-Takeover Effects

Certain provisions set forth in our Certificate of Incorporation and Bylaws and in Delaware law, which are summarized below, may be deemed to have an anti-takeover effect and may delay, deter or prevent a tender offer or takeover attempt that a stockholder might consider to be in its best interests, including attempts that might result in a premium being paid over the market price for the shares held by stockholders.

Pursuant to our Certificate of Incorporation, our Board of Directors may issue additional shares of common or preferred stock. Any additional issuance of common stock could have the effect of impeding or discouraging the acquisition of control of us by means of a merger, tender offer, proxy contest or otherwise, including a transaction in which our stockholders would receive a premium over the market price for their shares, and thereby protect the continuity of our management. Specifically, if in the due exercise of its fiduciary obligations, the Board of Directors were to determine that a takeover proposal was not in our best interest, shares could be issued by our Board of Directors

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without stockholder approval in one or more transactions that might prevent or render more difficult or costly the completion of the takeover by:

Our Certificate of Incorporation also allows our Board of Directors to fix the number of directors in our Bylaws. Cumulative voting in the election of directors is specifically denied in our Certificate of Incorporation. The effect of these provisions may be to delay or prevent a tender offer or takeover attempt that a stockholder may determine to be in his, her or its best interest, including attempts that might result in a premium over the market price for the shares held by the stockholders.

In addition to the foregoing, our Certificate of Incorporation and Bylaws contain the following provisions:

Staggered Board.  Our Board of Directors is divided into three classes of directors, Class I, II and III, with each class serving staggered 3-year terms.

Nominations of Directors and Proposals of Business.  Our Bylaws generally regulate nominations for election of directors by stockholders and proposals of business at annual meetings. In general, Sections 1.10 and 1.11 of our Bylaws require stockholders intending to submit nominations or proposals at an annual meeting of stockholders to provide the Company with advance notice thereof, including information regarding the nomination or the stockholder proposing the business as well as information regarding the nominee or the proposed business. Sections 1.10 and 1.11 of our Bylaws provide a time period during which nominations or business must be provided to the Company that will create a predictable window for the submission of such notices, eliminating the risk that the Company finds a meeting will be contested after printing its proxy materials for an uncontested election and providing the Company with a reasonable opportunity to respond to nominations and proposals by stockholders.

Board Vacancies. Our Bylaws generally provide that only the Board of Directors (and not the stockholders) may fill vacancies and newly created directorships.

Special Meeting of Stockholders.  Our Bylaws generally provide that special meetings of stockholders for any purpose or purposes for which meetings may be lawfully called, may be called at any time by our Board of Directors, the Chairman of the Board, the Chief Executive Officer or by one or more stockholders holding shares in the aggregate entitled to cast not less than fifty percent (50%) of the votes at that meeting. Business transacted at any special meeting of stockholders shall be limited to matters relating to the purpose or purposes stated in the notice of meeting.

While the foregoing provisions of our Certificate of Incorporation, Bylaws and Delaware law may have an anti-takeover effect, these provisions are intended to enhance the likelihood of continuity and stability in the composition of the Board of Directors and in the policies formulated by the Board of Directors and to discourage certain types of transactions that may involve an actual or threatened change of control. In that regard, these provisions are designed to reduce our vulnerability to an unsolicited acquisition proposal. The provisions also are intended to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging others from making tender offers for our shares and, as a consequence, they also may inhibit fluctuations in the market price of our common stock that could result from actual or rumored takeover attempts. Such provisions also may have the effect of preventing changes in our management.

Delaware Takeover Statute

In general, Section 203 of the Delaware General Corporation Law prohibits a Delaware corporation that is a public company from engaging in any “business combination” (as defined below) with any “interested stockholder” (defined generally as an entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with such entity or person) for a period of three years following the date that such

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stockholder became an interested stockholder, unless: (1) prior to such date, the board of directors of the corporation approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder; (2) on consummation of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding for purposes of determining the number of shares outstanding those shares owned (x) by persons who are directors and also officers and (y) by employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or (3) on or subsequent to such date, the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least two-thirds of the outstanding voting stock that is not owned by the interested stockholder.

Section 203 of the Delaware General Corporation Law defines “business combination” to include: (1) any merger or consolidation involving the corporation and the interested stockholder; (2) any sale, transfer, pledge or other disposition of ten percent or more of the assets of the corporation involving the interested stockholder; (3) subject to certain exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder; (4) any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested stockholder; or (5) the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.

Listing of Common Stock on the NYSE American

Our common stock is currently listed on the NYSE American under the trading symbol “IBIO.”

Transfer Agent

The transfer agent and registrar for our common stock is Continental Stock Transfer & Trust Company. They are located at 1 State Street, 30^th  floor, New York, New York 10004. Their telephone number is (212) 509-4000.