Exhibit 4.6

 DESCRIPTION OF XOMA CORPORATION CAPITAL STOCK

The following is a description of the Common Stock, $0.0075 par value (the “Common Stock”) and Preferred Stock, $0.05 par value (the “Preferred Stock”) of XOMA Corporation (the “Company”). The Common Stock and the 8.625% Series A Cumulative Perpetual Preferred Stock (the “Series A Preferred Stock”) are the only securities of the Company registered pursuant to Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

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Common Stock

General. The Company is authorized to issue up to 277,333,332 shares of Common Stock. The following description is based on (i) the Company’s Certificate of Incorporation, as currently in effect (the “Certificate of Incorporation”), (ii) the Company’s By-laws, as currently in effect (the “By-laws”), and (iii) the Delaware General Corporation Law (the “DGCL”). The following summary description of the Common Stock of the Company is qualified in its entirety by reference to the provisions of the Certificate of Incorporation and By-laws, copies of which have been filed as exhibits to the Company’s Annual Report filed herewith, and the applicable provisions of the DGCL.

Dividend Rights. The holders of our Common Stock have the right to receive dividends and distributions, whether payable in cash or otherwise, as may be declared from time to time by our board of directors, from legally available funds.

Voting Rights. Each holder of our Common Stock is generally entitled to one vote for each share of Common Stock owned of record on all matters submitted to a vote of our stockholders. Except as otherwise required by law, holders of Common Stock (as well as holders of any Preferred Stock entitled to vote with the common stockholders) will generally vote together as a single class on all matters presented to the stockholders for their vote or approval, including the election of directors. Any matter brought before the stockholders for a vote, other than the election of directors, will generally be decided by a majority of the votes cast on the matter, unless the matter is one in which an express provision of the DGCL, the Certificate of Incorporation, the By-laws, the rules or regulations of any stock exchange applicable to us, applicable law or pursuant to any regulation applicable to us or our securities requires a different vote, in which case the express provision will govern and control the decision of the matter. Directors will be elected by a plurality of the votes cast and entitled to vote generally on the election of directors. There are no cumulative voting rights with respect to the election of directors or any other matters.

No Preemptive or Similar Rights. Holders of our Common Stock have no redemption rights, conversion rights or preemptive rights to purchase or subscribe for our securities.

Right to Receive Liquidation Distributions. In the event of our liquidation, dissolution or winding-up, holders of our Common Stock will be entitled to share equally in the assets available for distribution after payment of all creditors and the liquidation preferences of our Preferred Stock (if any).

The rights of the holders of our Common Stock are subject to, and may be adversely affected by, the rights of holders of shares of any Preferred Stock that we may designate and issue in the future.

Preferred Stock

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General. Under our Certificate of Incorporation, our board of directors is authorized to issue up to 1,000,000 shares of Preferred Stock, and, by resolution, to divide the Preferred Stock into series and, with respect to each series, to determine the designations and the powers, preferences and rights, and the qualifications, limitations and restrictions thereof, including the dividend rights, conversion or exchange rights, voting rights, redemption rights and terms, liquidation preferences, sinking fund provisions and the number of shares constituting the series. Our board of directors can, without stockholder approval but subject to the terms of the Certificate of Incorporation and to any resolution of the stockholders approved by at least 75% of all issued shares entitled to vote in respect thereof, issue

Preferred Stock with voting and other rights that could adversely affect the voting power of the holders of our Common Stock and which could have certain anti-takeover effects. Before we may issue any series of Preferred Stock, our board of directors will be required to adopt resolutions creating and designating such series of Preferred Stock.

The following summary description of the Preferred Stock of the Company is qualified in its entirety by reference to the provisions of the Certificate of Incorporation, By-laws and the certificates of designation of preferences, rights and limitations of each series of the Preferred Stock, copies of which have been filed as exhibits to the Company’s Annual Report on Form 10-K, and the applicable provisions of the DGCL. As of December 31, 2020, 5,003 shares of Series X Preferred Stock and 984,000 shares of 8.625% Series A Cumulative Perpetual Preferred Stock (the “Series A Preferred Stock”) were issued and outstanding.

The 8.625% Series A Cumulative Perpetual Preferred Stock. We have designated 984,000 shares of our Preferred Stock as Series A Preferred Stock.

The Series A Preferred Stock will rank, as to dividend rights and rights upon our liquidation, dissolution or winding up:

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Dividends.  We will pay cumulative cash dividends on the Series A Preferred Stock, when and as declared by our board of directors, at the rate of 8.625% of the $25.00 liquidation preference per share per year (equivalent to $2.15625 per year). Dividends will be payable quarterly in arrears, on or about the 15th day of January, April, July and October, beginning on or about April 15, 2021; provided that if any dividend payment date is not a business day, then the dividend which would otherwise have been payable on that dividend payment date may be paid on the next succeeding business day, and no interest, additional dividends or other sums will accumulate. Dividends will accumulate and be cumulative from, and including, the date of original issuance, which is expected to be December 15, 2020. The first dividend, which is scheduled to be paid on or about April 15, 2021 in the amount of $0.71875 per share of Series A Preferred Stock, will be for more than a full quarter and will cover the period from, and including, the first date we issue and sell the Series A Preferred Stock through, but not including, April 15, 2021. Dividends on the Series A Preferred Stock will continue to accumulate whether or not (i) any of our agreements prohibit the current payment of dividends, (ii) we have earnings or funds legally available to pay the dividends, or (iii) our board of directors does not declare the payment of the dividends.

Liquidation Preference. The liquidation preference of each share of Series A Preferred Stock is $25.00. Upon liquidation, holders of our Series A Preferred Stock will be entitled to receive the liquidation preference with respect to their shares of Series A Preferred Stock plus an amount equal to accumulated but unpaid dividends with respect to such shares.

Optional Redemption. On and after December 15, 2021, the first anniversary of December 15, 2020, to but excluding the second anniversary, the shares of Series A Preferred Stock will be redeemable at our option, in whole or in part, at a redemption price equal to $26.00 per Preferred Share, plus any accrued and unpaid dividends. On and

after December 15, 2022, the second anniversary of December 15, 2020, to but excluding the third anniversary, the shares of Series A Preferred Stock will be redeemable at our option, in whole or in part, at a redemption price equal to $25.75 per Preferred Share, plus any accrued and unpaid dividends. On and after December 15, 2023, the third anniversary of December 15, 2020, to but excluding the fourth anniversary, the shares of Series A Preferred Stock will be redeemable at our option, in whole or in part, at a redemption price equal to $25.50 per Preferred Share, plus any accrued and unpaid dividends. On and after December 15, 2024, the fourth anniversary of December 15, 2020, to but excluding the fifth anniversary, the shares of Series A Preferred Stock will be redeemable at our option, in whole or in part, at a redemption price equal to $25.25 per Preferred Share, plus any accrued and unpaid dividends. On and after December 15, 2025, the fifth anniversary of December 15, 2020, the shares of Series A Preferred Stock will be redeemable at our option, in whole or in part, at a redemption price equal to $25.00 per Preferred Share, plus any accrued and unpaid dividends. We may not redeem the shares of Series A Preferred Stock before the first anniversary of December 15, 2020, except as described below.

Special Optional Redemption Upon a Change of Control or Delisting Event. Upon the occurrence of a Delisting Event (as defined below), we may, at our option, redeem the Series A Preferred Stock, in whole or in part, within 90 days after the first date on which such Delisting Event occurred, for cash, at a redemption price of $25.00 per share, plus any accrued and unpaid dividends up to, but not including, the date of redemption.

A “Delisting Event” occurs when, after the original issuance of Series A Preferred Stock, both (i) the shares of Series A Preferred Stock are no longer listed on Nasdaq, the New York Stock Exchange (the “NYSE”) or the NYSE American LLC (“NYSE AMER”), or listed or quoted on an exchange or quotation system that is a successor to Nasdaq, the NYSE or the NYSE AMER, and (ii) we are not subject to the reporting requirements of the Exchange Act, but any Series A Preferred Stock is still outstanding.

Upon the occurrence of a Change of Control (as defined below), we may, at our option, redeem the Series A Preferred Stock, in whole or in part within 120 days after the first date on which such Change of Control occurred, for cash, at a redemption price of $25.00 per share, plus any accrued and unpaid dividends up to, but not including, the date of redemption.

A “Change of Control” occurs when, after the original issuance of the Series A Preferred Stock, the following have occurred and are continuing:

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We refer to redemption following a Delisting Event or Change of Control as a “special optional redemption.” If, prior to the Delisting Event Conversion Date (as defined below) or the Change of Control Conversion Date (as defined below), as applicable, we have provided or provide notice of exercise of any of our redemption rights relating to the Series A Preferred Stock (whether our optional redemption right or our special optional redemption right), the holders of the Series A Preferred Stock will not have the conversion right described below.

Conversion. Upon the occurrence of a Delisting Event or a Change of Control, as applicable, each holder of Series A Preferred Stock will have the right (unless, prior to the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable, we have provided or provide notice of our election to redeem the Series A Preferred Stock) to convert some or all of the Series A Preferred Stock held by such holder on the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable, into a number of shares of our common stock (or equivalent value of alternative consideration) per share of Series A Preferred Stock equal to the lesser of:

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If, prior to the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable, we have provided or provide a redemption notice, whether pursuant to our special optional redemption right or our optional redemption right, holders of Series A Preferred Stock will not have any right to convert the Series A Preferred Stock, and any Series A Preferred Stock subsequently selected for redemption that has been tendered for conversion will be redeemed on the related date of redemption instead of converted on the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable.

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In the event that the conversion would result in the issuance of fractional shares of common stock, we will pay the holder of Series A Preferred Stock cash in lieu of such fractional shares.

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Except as provided above in connection with a Delisting Event or Change of Control, shares of the Series A Preferred Stock are not convertible into or exchangeable for any other securities or property.

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For purposes of this description, “Change of Control Conversion Date” means a business day fixed by our board of directors that is not fewer than 20 days nor more than 35 days after the date on which we provide notice to the holders of the Series A Preferred Stock of a Change of Control.

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For purposes of this description, “Common Stock Price” for any Change of Control will be: (1) if the consideration to be received in the Change of Control by the holders of our common stock is solely cash, the amount of cash consideration per share of common stock; and (2) if the consideration to be received in the Change of Control by holders of our common stock is other than solely cash (x) the average of the closing prices for our common stock on the principal U.S. securities exchange on which our common stock is then traded (or, if no closing sale price is reported, the average of the closing bid and ask prices per share or, if more than one in either case, the average of the average closing bid and the average closing ask prices per share) for the ten consecutive trading days immediately preceding, but not including, the date on which such Change of Control occurred as reported on the principal U.S. securities exchange on which our common stock is then traded, or (y) the average of the last quoted bid prices for our common stock in the over-the-counter market as reported by OTC Markets Group Inc. or similar organization for the ten consecutive trading days immediately preceding, but not including, the date on which such Change of Control occurred, if our common stock is not then listed for trading on a U.S. securities exchange. The “Common Stock Price” for any Delisting Event will be the average of the closing price per share of our common stock on the 10 consecutive trading days immediately preceding, but not including, the effective date of the Delisting Event.

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For purposes of this description, “Delisting Event Conversion Date” means a business day fixed by our board of directors that is not fewer than 20 days nor more than 35 days after the date on which we provide notice to the holders of the Series A Preferred Stock of a Delisting Event.

Voting Rights. Holders of Series A Preferred Stock generally will have no voting rights. However, if we do not pay dividends on any outstanding shares of Series A Preferred Stock for six or more quarterly dividend periods (whether or not declared or consecutive), holders of Series A Preferred Stock (voting separately as a class with all other outstanding series of preferred stock upon which like voting rights have been conferred and are exercisable) will be entitled to elect two additional directors to our board of directors to serve until all unpaid dividends have been fully paid or declared and set apart for payment. In addition, certain material and adverse changes to the terms of the Series A Preferred Stock cannot be made without the affirmative vote of holders of at least 66 2/3% of the outstanding shares of Series A Preferred Stock, voting as a separate class. In any matter in which the Series A Preferred Stock may vote, each share of Series A Preferred Stock shall be entitled to one vote.

Anti-takeover Effects of Provisions of our Certificate of Incorporation and By-laws and Delaware Law

Certificate of Incorporation and By-laws Provisions. Our Certificate of Incorporation authorizes our board of directors to issue up to 1,000,000 shares of Preferred Stock without stockholder approval and to set the rights, preferences and other designations, including voting rights, of those shares as the board of directors may determine. In addition, our By-laws require certain procedures to be followed and time periods to be met for any stockholder to propose matters to be considered at annual meetings of stockholders, including nominating directors for election at those meetings. Our By-laws also provide that our board of directors is able to elect a director to fill a vacancy created by the expansion of the board of directors or due to the resignation or departure of an existing board member. Provisions of Delaware law and our Certificate of Incorporation and By-laws could make the acquisition of our company through a tender offer, a proxy contest or other means more difficult and could make the removal of incumbent officers and directors more difficult. We expect these provisions to discourage coercive takeover practices and inadequate takeover bids and to encourage persons seeking to acquire control of our company to first negotiate with our board of directors. We believe that the benefits provided by our ability to negotiate with the proponent of an unfriendly or unsolicited proposal outweigh the disadvantages of discouraging these proposals. We believe the negotiation of an unfriendly or unsolicited proposal could result in an improvement of its terms.

Delaware Law. We are subject to Section 203 of the DGCL, an anti-takeover law. In general, Section 203 prohibits a publicly held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years following the date the person became an interested stockholder, unless:

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Generally, a “business combination” includes a merger, asset or stock sale, or other transaction resulting in a financial benefit to the interested stockholder. An “interested stockholder” is a person who, together with affiliates and associates, beneficially owns, or is an affiliate of the corporation and within three years prior to the determination of interested stockholder status did own, 15% or more of a corporation’s outstanding voting securities. We expect the existence of this provision to have an anti-takeover effect with respect to transactions our board of directors does not approve in advance.

The Series X Preferred Stock. We have designated 5,003 shares of our Preferred Stock as Series X Preferred Stock. The Series X Preferred Stock ranks:

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in each case, as to distributions of assets upon our liquidation, dissolution or winding up whether voluntarily or involuntarily.

Dividends. Holders of Series X Preferred Stock are entitled to receive dividends on shares of Series X Preferred Stock equal (on an as-converted basis) to and in the same form as dividends actually paid on our Common Stock or other junior securities.

Liquidation Preference. In the event of our liquidation, dissolution, or winding up, holders of our Series X Preferred Stock will participate pari passu (on an as-converted basis, without regard to any blocker provisions) with any distribution of proceeds to holders of our Common Stock.

Redemption. We are not obligated to redeem or repurchase any shares of Series X Preferred Stock. Shares of Series X Preferred Stock are not otherwise entitled to any redemption rights or mandatory sinking fund or analogous fund provisions.

Conversion. The Series X Preferred Stock is convertible at the option of the holders thereof at any time after issuance into the number of registered shares of Common Stock determined by dividing the aggregate stated value of the Series X Preferred Stock being converted by the conversion price then in effect. The initial conversion price is $4.03 and is subject to adjustment as described below. No holder may request a conversion of its Series X Preferred Stock to the extent such conversion would result in the holder and its affiliates beneficially owning more than a pre-set conversion blocker threshold, which will initially be set at 19.99% of our Common Stock then outstanding (the “Beneficial Ownership Limitation”). The amount of beneficial ownership of a holder and its affiliates will be determined in accordance with Section 13(d) of the Securities Exchange Act of 1934, as amended, and the rules and regulations of that section.

Conversion Price Adjustment—Stock Dividends and Stock Splits. If we pay a stock dividend or otherwise make a distribution payable in Common Stock on our Common Stock or any Common Stock equivalents, subdivide or combine our outstanding Common Stock, or reclassify our Common Stock in such a way that we issue additional shares of our capital stock, the conversion price will be adjusted by multiplying the then-existing conversion price by a fraction, the numerator of which is the number of shares of Common Stock outstanding immediately before the distribution, dividend, adjustment or recapitalization and the denominator of which is the number of shares of Common Stock outstanding immediately after such action.

Fundamental Transaction. If we effect a “fundamental transaction” (as defined below), then upon any future conversion of the Series X Preferred Stock, the holders will have the right to receive, for each share of Common Stock they would have received upon such conversion, the same kind and amount of securities, cash or property as such holder would have been entitled to receive in the fundamental transaction had it been the holder of Common Stock immediately prior to the fundamental transaction. The term “fundamental transaction” means any of the following:

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If the holders of Common Stock are given a choice as to the securities, cash or property to be received in a fundamental transaction, the holders of Series X Preferred Stock will be given the same choice on conversion of such holders’ shares.

Voting Rights. The Series X Preferred Stock has no voting rights, except to the extent expressly provided in our Certificate of Incorporation or as otherwise required by law. However, so long as 2,502 shares of Series X Preferred Stock are outstanding, we may not take any of the following actions without the affirmative consent of holders of a majority of the outstanding Series X Preferred Stock:

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