XOMA 424B5 Prospectus supplement for primary offering

Filed Pursuant to Rule 424(b)(5)
Registration No. 333-223493

The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying base prospectus are not an offer to sell these securities, and are not soliciting an offer to buy these securities, in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION—DATED DECEMBER 10, 2020

PRELIMINARY PROSPECTUS SUPPLEMENT

(To Prospectus dated April 5, 2018)

LOGO

XOMA CORPORATION

Shares of % Series A Cumulative Perpetual Preferred Stock

(Liquidation Preference of $25.00 Per Share)

We are offering for sale shares of our % Series A Cumulative Perpetual Preferred Stock, par value $0.05 per share (the “Series A Preferred Stock”). The liquidation preference of each share of Series A Preferred Stock is $25.00.

We will pay cumulative distributions on the Series A Preferred Stock, from, and including, the date of original issuance, in the amount of $ per share each year, which is equivalent to % of the $25.00 liquidation preference per share. Dividends on the Series A Preferred Stock will be payable quarterly in arrears, on or about the 15th day of January, April, July and October of each year (or, if not on a business day, on the next succeeding business day). The first dividend on the Series A Preferred Stock sold in this offering will be paid on or about April 15, 2021. We will establish a segregated account that will be funded at closing with proceeds sufficient to pre-fund with four (4) quarterly dividend payments. The segregated account may only be used to pay dividends on the Series A Preferred Stock, when legally permitted, and may not be used for other corporate purposes.

Investing in our Series A Preferred Stock involves risks. See the section entitled “Risk Factors” beginning on page S-11 of this prospectus supplement and in our Quarterly Report on Form 10-Q for the for the fiscal quarter ended September 30, 2020, which has been filed with the Securities and Exchange Commission and is hereby incorporated by reference in this prospectus supplement and the accompanying prospectus, to read about factors you should consider before buying our Series A Preferred Stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying base prospectus is truthful or complete. Any representation to the contrary is a criminal offense.


	Per Share	Total
Public offering price(1)	$	$
Underwriting discount(2)	$	$
Proceeds to us, before expenses(3)	$	$

(1)	Plus accrued dividends, if any, from the original date of issuance.

(2)	See “Underwriting” for a description of all underwriting compensation payable in connection with this offering.

(3)	Assumes no exercise of the underwriters’ option described below.

We have granted the underwriters an option to purchase up to an additional shares of Series A Preferred Stock within 30 days from the date of this prospectus supplement. If the underwriters exercise the option in full, the total underwriting discounts and commissions payable by us will be $ (excluding the structuring fee), and the total proceeds to us, before payment of the structuring fee and expenses will be $ .

Certain of our existing stockholders, officers, directors and their affiliated entities have indicated an interest in purchasing up to approximately $ of shares of our Series A Preferred Stock at the public offering price. However, because indications of interest are not binding agreements or commitments to purchase, the underwriters may determine to sell more, less or no shares in this offering to any of these stockholders, officers, directors or their affiliates, or any of these stockholders, officers, directors or their affiliates may determine to purchase more, less or no shares in this offering.

The underwriters expect to deliver the shares of Series A Preferred Stock on or about December , 2020.

Joint Book-Runners


B. Riley Securities		Ladenburg Thalmann		National Securities Corporation		William Blair & Company

Co-Managers


Aegis Capital Corp.		Boenning & Scattergood		Northland Capital Markets

The date of this prospectus supplement is December , 2020.

Generally, we may not redeem the Series A Preferred Stock until December , 2021, and except as described below upon the occurrence of a Delisting Event or Change of Control (each as defined herein), as applicable. On and after December , 2021 the first anniversary of December , 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 , 2022 the second anniversary of December , 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 , 2023, third anniversary of December , 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 , 2024, fourth anniversary of December , 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 , 2025, the fifth anniversary of December , 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. In addition, upon the occurrence of a Delisting Event or a Change of Control (each as defined herein), we may, subject to certain conditions, 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 or within 120 days after the first date on which such Change of Control occurred, as applicable, by paying $25.00 per share, plus any accumulated and unpaid dividends up to, but not including, the redemption date. If we exercise any of our redemption rights relating to the Series A Preferred Stock, the holders of Series A Preferred Stock will not have the conversion right described below.

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 (each as defined herein), we have provided or provide notice of our election to redeem the Series A Preferred Stock) to convert some or all of the shares of 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 per share of Series A Preferred Stock equal to the lesser of:

•

the quotient obtained by dividing (i) the sum of the $25.00 liquidation preference plus the amount of any accumulated and unpaid dividends thereon up to, but not including, the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable (unless the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable, is after a record date for a Series A Preferred Stock dividend payment and prior to the corresponding Series A Preferred Stock dividend payment date, in which case no additional amount for such accumulated and unpaid dividend will be included in this sum) by (ii) the Common Stock Price (as defined herein); and

•

(i.e., the “Share Cap”), subject to certain adjustments;

subject, in each case, to the conditions described in this prospectus supplement, including, under specified circumstances, an aggregate cap on the total number of shares of common stock issuable upon conversion and to the provisions for the receipt of alternative consideration contained herein.

The Series A Preferred Stock has no maturity date and will remain outstanding indefinitely unless redeemed by us or converted into shares of common stock in connection with a Delisting Event or Change of Control by the holders of the Series A Preferred Stock. Investors in the Series A Preferred Stock generally will have no voting rights, but will have limited voting rights if we fail to pay dividends for six or more quarters (whether or not declared or consecutive) and in certain other events.

We have applied to list the Series A Preferred Stock on The Nasdaq Global Market (“Nasdaq”) under the symbol “XOMAP.” If the application is approved, we expect trading on Nasdaq will commence within 30 days after the initial delivery of the Series A Preferred Stock to the underwriters.

TABLE OF CONTENTS

Prospectus Supplement


	Page
About This Prospectus Supplement		S-1
Forward-Looking Statements		S-3
Prospectus Supplement Summary		S-4
Risk Factors		S-11
Use of Proceeds		S-17
Capitalization		S-18
Description of Series A Preferred Stock		S-19
Book-Entry, Delivery and Form		S-30
Material U.S. Federal Income Tax Considerations		S-32
Underwriting		S-38
Legal Matters		S-42
Experts		S-42
Where You Can Find More Information		S-42
Incorporation of Certain Information by Reference		S-43

Prospectus
About this Prospectus		i
Prospectus Summary		1
Risk Factors		5
Forward-Looking Statements		5
Financial Ratios		6
Use of Proceeds		6
Description of Capital Stock		7
Description of Debt Securities		13
Description of Warrants		20
Legal Ownership of Securities		22
Plan of Distribution		26
Legal Matters		28
Experts		28
Where You Can Find More Information		28
Incorporation of Certain Information by Reference		29

ABOUT THIS PROSPECTUS SUPPLEMENT

This document is part of the registration statement that we filed with the Securities and Exchange Commission (the “SEC”) using a “shelf” registration process and consists of two parts. The first part is this prospectus supplement, including the documents incorporated by reference herein, which describes the specific terms of this offering. The second part, the accompanying base prospectus, including the documents incorporated by reference therein, gives more general information, some of which may not apply to this offering. Generally, when we refer only to the “prospectus,” we are referring to both parts combined. This prospectus supplement may add to, update or change information in the accompanying base prospectus and the documents incorporated by reference into this prospectus supplement or the accompanying base prospectus.

If information in this prospectus supplement is inconsistent with the accompanying base prospectus or with any document incorporated by reference therein that was filed with the SEC before the date of this prospectus supplement, you should rely on this prospectus supplement. This prospectus supplement, the accompanying base prospectus and the documents incorporated by reference herein and therein include important information about us, the securities being offered and other information you should know before investing in our securities. You should read the entire prospectus supplement and the accompanying base prospectus carefully, including the “Risk Factors” contained in this prospectus supplement, the accompanying base prospectus and the documents incorporated by reference herein and therein and the financial statements incorporated by reference in this prospectus supplement and the accompanying base prospectus, before making an investment decision. You should also read and consider information in the documents we have referred you to in the section of this prospectus supplement and the accompanying base prospectus entitled “Where You Can Find More Information” and “Incorporation of Certain Information by Reference” as well as any free writing prospectus provided in connection with this offering.

You should rely only on this prospectus supplement, the accompanying base prospectus, and any free writing prospectus provided in connection with this offering and the information incorporated or deemed to be incorporated by reference in this prospectus supplement and the accompanying base prospectus. We have not, and the underwriters have not, authorized anyone to provide you with information that is in addition to or different from that contained or incorporated by reference in this prospectus supplement, the accompanying base prospectus, and any free writing prospectus provided in connection with this offering. If anyone provides you with different or inconsistent information, you should not rely on it. We and the underwriters take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. You should not assume that the information contained or incorporated by reference in this prospectus supplement, the accompanying base prospectus, or any free writing prospectus provided in connection with this offering is accurate as of any date other than as of the date of this prospectus supplement, the accompanying base prospectus, or such free writing prospectus, as the case may be, or in the case of the documents incorporated by reference, the date of such documents, regardless of the time of delivery of this prospectus supplement and the accompanying base prospectus or any sale of our securities. Our business, financial condition, liquidity, results of operations and prospects may have changed since those dates.

We are offering to sell, and seeking offers to buy, our securities only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the offering of the securities in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement must inform themselves about, and observe any restrictions relating to, the offering of the securities and the distribution of this prospectus supplement outside the United States. This prospectus supplement does not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

S-1

Any industry and market data and other statistical information contained in this prospectus supplement, the accompanying base prospectus and the documents we incorporate by reference herein or therein are based on management’s estimates, independent publications, government publications, reports by market research firms or other published independent sources, and, in each case, are believed by management to be reasonable estimates. Although we believe these sources are reliable, we have not independently verified the information. None of the independent industry publications used in this prospectus supplement, the accompanying base prospectus or the documents we incorporate by reference herein or therein, if any, were prepared on our or our affiliates’ behalf and none of the sources cited by us consented to the inclusion of any data from its reports, nor have we sought their consent.

Unless the context indicates otherwise or as otherwise expressly stated, references in this prospectus supplement to the “Company,” “XOMA,” “we,” “us,” “our” and similar terms refer to XOMA Corporation and its subsidiaries and references in this prospectus supplement to “common stock,” “our common stock,” “shares of common stock” and similar terms refer to shares of common stock of XOMA Corporation.

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FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying base prospectus and the documents incorporated by reference herein and therein may contain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 concerning our business, operations, financial performance, and condition, as well as our plans, objectives, and expectations for our business operations and financial performance and condition. Any statements contained herein that are not of historical facts may be deemed to be forward-looking statements. You can identify these statements by words such as “aim,” “anticipate,” “assume,” “believe,” “could,” “due,” “estimate,” “expect,” “goal,” “intend,” “may,” “objective,” “plan,” “predict,” “potential,” “positioned,” “should,” “target,” “will,” “would” and other similar expressions that are predictions of or indicate future events and future trends. Examples of these statements include, but are not limited to, any statements regarding: the sufficiency of our cash resources, our future operating expenses, our future losses, the extent to which our issued and pending patents may protect our products and technology, the potential of our existing product candidates to lead to the development of commercial products, our ability to receive potential milestone or royalty payments under license, collaboration and royalty purchase agreements and the timing of receipt of those payments, the timing and adequacy of cost-cutting measures, and our ability to defend against claims that have been or may be made in litigation or arbitration proceedings. These statements are based on assumptions that may not prove accurate. Actual results could differ materially from those anticipated due to certain risks inherent in the biotechnology industry and for our licensees engaged in the development of new products in a regulated market. Among other things, these risks include: our product candidates subject to out-license agreements are still being developed, and our licensees may require substantial funds to continue development which may not be available; we may not realize the expected benefits of our cost-saving initiatives; we may not be successful in entering into out-license agreements for our product candidates; if our therapeutic product candidates do not receive regulatory approval, our third-party licensees will not be able to manufacture and market them; products or technologies of other companies may render some or all of our product candidates noncompetitive or obsolete; we do not know whether there will be, or will continue to be, a viable market for the products in which we have an ownership or royalty interest; even once approved, a product may be subject to additional testing or significant marketing restrictions, its approval may be withdrawn or it may be voluntarily taken off the market; we and our licensees are subject to various state and federal healthcare related laws and regulations that may impact the commercialization of our product candidates and could subject us to significant fines and penalties; and certain of our technologies are in-licensed from third parties, so our capabilities using them are restricted and subject to additional risks.

These forward-looking statements are based on current expectations, estimates, forecasts, projections about our business and the industry in which we operate, and our management’s beliefs and assumptions. They are not guarantees of future performance or development and involve known and unknown risks, uncertainties, and other factors that are in some cases beyond our control. As a result, any or all of our forward-looking statements in this prospectus supplement, the accompanying base prospectus and the documents incorporated by reference herein and therein may turn out to be inaccurate or could cause our actual results to differ materially from historical results or from any results expressed or implied by such forward-looking statements.

You are urged to consider these factors carefully in evaluating the forward-looking statements and are cautioned not to place undue reliance on the forward-looking statements. These forward-looking statements speak only as of the date hereof. Unless required by law, we do not intend to publicly update or revise any forward-looking statements to reflect new information or future events or otherwise. You should, however, review the factors and risks we describe in the reports we will file from time to time with the SEC after the date of this prospectus supplement.

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PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights the information contained elsewhere in or incorporated by reference into this prospectus supplement and the accompanying prospectus. This summary does not contain all of the information that you should consider before deciding whether to invest in our Series A Preferred Stock. You should carefully read this entire prospectus supplement, including the information under the heading “Risk Factors,” and the documents incorporated by reference into this prospectus supplement and the accompanying prospectus, which are described under the headings “Where You Can Find More Information” and “Incorporation of Certain Information by Reference.”

You should rely only on the information contained in this prospectus supplement and the accompanying prospectus. We have not authorized anyone to provide you with information different from the information contained in this prospectus supplement or the accompanying prospectus. The information contained in this prospectus supplement is accurate only as of the date of this prospectus supplement, regardless of when this prospectus supplement is delivered or when any sale of our securities occurs.

The Company

We have a long history of discovering and developing innovative therapeutics derived from our unique platform of antibody technologies. Over our extensive history, we built a pipeline of drug product development candidates we discovered and advanced prior to licensing them to licensees who assumed the responsibilities of subsequent development, regulatory approval and commercialization (i.e., “Fully-funded programs”). Fully-funded programs are those for which our partners pay the development and commercialization costs. As licensees advance these programs, we are eligible for potential development, regulatory and commercial milestone and royalty payments.

In March 2017, we transformed our business model to become a royalty aggregator where we focus on expanding our portfolio of Fully-funded programs by out-licensing our internally developed product candidates and acquiring potential milestone and royalty revenue streams on additional drug development product candidates. As part of our royalty aggregator business model, we intend to continue to expand our pipeline of Fully-funded programs by acquiring potential milestone and royalty revenue streams on additional drug development product candidates from third parties. We combined our royalty aggregator model with a significantly reduced corporate cost structure in order to further build value for our shareholders. Our long-term prospects depend upon the ability of our partners to successfully commercialize new drug products.

Additional Company Information

We were incorporated in Delaware in 1981 and became a Bermuda-exempted company in December 1998. Effective December 31, 2011, we changed our jurisdiction of incorporation from Bermuda to Delaware and changed our name from XOMA Ltd. to XOMA Corporation.

Our principal executive offices are located at 2200 Powell Street, Suite 310, Emeryville, California 94608, and we maintain a registered office located at Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware 19801. Our telephone number at our principal executive offices is (510) 204-7200. Our website address is www.xoma.com. The information found on our website is not part of this or any other report filed with or furnished to the Securities and Exchange Commission (“SEC”).

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THE OFFERING

Issuer

XOMA Corporation

Securities offered

shares of % Series A Cumulative Perpetual Preferred Stock, par value $0.05 per share (or shares if the underwriters exercise their option to purchase additional shares in full).

We reserve the right to re-open this series of preferred stock and issue additional shares of Series A Preferred Stock either through public or private sales at any time and from time to time, without notice to or consent of holders of the Series A Preferred Stock. The additional shares would form a single series together with all previously issued shares of Series A Preferred Stock.

Option to purchase additional shares

We have granted the underwriters an option for a period of 30 days from the date of this prospectus supplement to purchase up to an additional shares of Series A Preferred Stock.

Ranking

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

Senior to all classes or series of our common stock and to all other equity securities issued by us expressly designated as ranking junior to the Series A Preferred Stock;

Senior with respect to the payment of dividends and on parity with respect to the distribution of assets upon our liquidation, dissolution or winding up with our Series X Preferred Stock and on parity with any future class or series of our equity securities expressly designated as ranking on parity with the Series A Preferred Stock;

Junior to all equity securities issued by us with terms specifically providing that those equity securities rank senior to the Series A Preferred Stock with respect to the payment of dividends and the distribution of assets upon our liquidation, dissolution or winding up, none of which exists on the date hereof; and

Effectively junior to all our existing and future indebtedness (including indebtedness convertible into our common stock or preferred stock) and to the indebtedness and other liabilities of (as well as any preferred equity interests held by others in) our existing or future subsidiaries.

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 % of the $25.00 liquidation preference per share per year (equivalent to $ 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

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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 , 2020. The first dividend, which is scheduled to be paid on or about April 15, 2021 in the amount of $ 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 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. See “Description of Series A Preferred Stock—Liquidation Preference” on page S-21 of this prospectus supplement.

Optional redemption

On and after December , 2021 the first anniversary of December , 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 , 2022 the second anniversary of December , 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 , 2023, third anniversary of December , 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 , 2024, fourth anniversary of December , 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 , 2025, the fifth anniversary of December , 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 , 2020, except as described under

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“Description of Series A Preferred Stock—Special Optional Redemption” in this prospectus supplement.

Special optional redemption

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 Securities Exchange Act of 1934, as amended (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:

•

the acquisition by any person, including any syndicate or group deemed to be a “person” under Section 13(d)(3) of the Exchange Act, of beneficial ownership, directly or indirectly, through a purchase, merger or other acquisition transaction or series of purchases, mergers or other acquisition transactions of shares of our company entitling that person to exercise more than 50% of the total voting power of all shares of our company entitled to vote generally in elections of directors (except that such person will be deemed to have beneficial ownership of all securities that such person has the right to acquire, whether such right is currently exercisable or is exercisable only upon the occurrence of a subsequent condition); and

•

following the closing of any transaction referred to in the bullet point above, neither we nor any acquiring or surviving entity (or if, in connection with such transaction shares of our common stock are converted into or exchanged for (in whole or in part) common equity securities of another entity), has a class of common securities (or ADRs representing such securities) listed on Nasdaq, the NYSE or the NYSE AMER, or listed or quoted

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on an exchange or quotation system that is a successor to Nasdaq, the NYSE or the NYSE AMER.

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 or the Change of Control Conversion Date, 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 rights

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:

•

the quotient obtained by dividing (1) the sum of the $25.00 per share liquidation preference plus the amount of any accumulated and unpaid dividends up to, but not including, the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable (unless the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable is after a record date for a Series A Preferred Stock dividend payment and prior to the corresponding Series A Preferred Stock dividend payment date, in which case no additional amount for such accumulated and unpaid dividend will be included in this sum) by (2) the Common Stock Price (as defined herein); and

•

(i.e., the Share Cap), subject to certain adjustments;

and subject, in each case, to the conditions described in this prospectus supplement, including, under specified circumstances, an aggregate cap on the total number of shares of our common stock issuable upon conversion and to provisions for the receipt of alternative consideration.

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

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the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable.

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.

For a definition of “Change of Control Conversion Right”, “Change of Control Conversion Date,” “Common Stock Price,” “Delisting Event Conversion Right,” and “Delisting Event Conversion Date” and for a description of the adjustments and provisions for the receipt of alternative consideration that may be applicable to the Delisting Event Conversion Right or Change of Control Conversion Right described above, see “Description of Series A Preferred Stock—Conversion Rights.”

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.

Segregated dividend payment account

We will establish a segregated account that will be funded at closing with proceeds sufficient to pre-fund four (4) quarterly dividend payments. The segregated account may only be used to pay dividends on the Series A Preferred Stock, when legally permitted, and may not be used for other corporate purposes.

No maturity, sinking fund or mandatory redemption

The Series A Preferred Stock does not have any stated maturity date and is not subject to mandatory redemption at the option of the holder or any sinking fund. We are not required to set aside funds to redeem the Series A Preferred Stock. Accordingly, the shares of Series A Preferred Stock will remain outstanding indefinitely unless we decide to redeem them pursuant to our optional redemption or special optional redemption rights, or they are converted in connection with a Delisting Event or Change of Control.

Limited 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. See “Description of Series A Preferred Stock—Limited Voting Rights” beginning on page S-28 of this prospectus supplement. In any matter in which the Series A

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Preferred Stock may vote, each share of Series A Preferred Stock shall be entitled to one vote.

Use of proceeds

We intend to use the net proceeds from this offering to fund the segregated dividend account and the remaining net proceeds for general corporate purposes, including, but not limited to, funding future acquisitions of milestone and royalty rights associated with drug development programs with third-party funding. See “Use of Proceeds” on page S-17 of this prospectus supplement.

Risk factors

An investment in the Series A Preferred Stock involves risks. You should carefully consider the discussion of risks in “Risk Factors” in this prospectus supplement and the other information included in or incorporated by reference in this prospectus supplement and the accompanying base prospectus before making an investment decision.

Material federal income tax considerations

Material federal income tax considerations of purchasing, owning and disposing of the Series A Preferred Stock are summarized in “Material U.S. Federal Income Tax Considerations” in this prospectus supplement.

Listing

No current market exists for the Series A Preferred Stock. We have applied to list the Series A Preferred Stock on Nasdaq under the symbol “XOMAP.” If the application is approved, we expect trading on Nasdaq will commence within 30 days after the initial delivery of the Series A Preferred Stock to the underwriters. We cannot assure you that our listing application will be approved within 30 days or at all.

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RISK FACTORS

An investment in our stock involves a high degree of risk. You should carefully read and consider the risks described below, together with the other information contained in or incorporated by reference into this prospectus supplement and the accompanying prospectus, including under the heading “Risk Factors” in our Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2020 before making a decision to invest in our common stock. The risks described below are not the only risks we face. Additional risks and uncertainties not currently known to us or that we currently deem to be immaterial may also materially and adversely affect our business operations. If any of the following risks actually occurs, our business, results of operations and financial condition could suffer. In that case, the trading price of our common stock could decline, and you may lose all or part of your investment.

Risks Related to this Offering and to the Series A Preferred Stock

There is no established market for the Series A Preferred Stock and the market value of the Series A Preferred Stock could be substantially affected by various factors.

The shares of Series A Preferred Stock are a new issue of securities with no established trading market. We intend to apply to list the Series A Preferred Stock on Nasdaq. Our listing application may not be approved by the Nasdaq. Further, even if approved for listing by the Nasdaq, an active trading market on Nasdaq for the Series A Preferred Stock may not develop or last, in which case the trading price of the Series A Preferred Stock could be adversely affected and/or sufficient liquidity to dispose of Series A Preferred Stock may not exist. If an active trading market does develop on Nasdaq, the shares of Series A Preferred Stock may trade at prices higher or lower than their initial offering price.

The trading price of the Series A Preferred Stock would also depend on many factors, including:

•

prevailing interest rates;

•

the market for similar securities;

•

general economic and financial market conditions;

•

our financial condition, results of operations and prospects; and

•

the matters discussed in this prospectus supplement under the captions “Risk Factors” and “Cautionary Note Regarding Forward-Looking Statements” and in our Annual Report on Form 10-K, or any updates in our Quarterly Reports on Form 10-Q and Current Reports on Form 8-K.

We have been advised by some of the underwriters that they intend to make a market in the Series A Preferred Stock, but they are not obligated to do so and may discontinue market-making at any time without notice.

The shares of Series A Preferred Stock are subject to our rights of redemption.

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accrued and unpaid dividends. On and after December , 2025, the fifth anniversary of December , 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.

The Series A Preferred Stock rank junior to all of our indebtedness and other liabilities and are effectively junior to all indebtedness and other liabilities of our subsidiaries.

In the event of our bankruptcy, liquidation, dissolution or winding-up of our affairs, our assets will be available to pay obligations on the Series A Preferred Stock only after all of our indebtedness and other liabilities have been paid. The rights of holders of the Series A Preferred Stock to participate in the distribution of our assets will rank junior to the prior claims of our current and future creditors and any future series or class of preferred stock we may issue that ranks senior to the Series A Preferred Stock. In addition, the Series A Preferred Stock effectively ranks junior to all existing and future indebtedness and other liabilities of (as well as any preferred equity interests held by others in) our existing subsidiaries and any future subsidiaries. Our existing subsidiaries are and any future subsidiaries would be separate legal entities and have no legal obligation to pay any amounts to us in respect of dividends due on the Series A Preferred Stock. If we are forced to liquidate our assets to pay our creditors, we may not have sufficient assets to pay amounts due on any or all of the Series A Preferred Stock then outstanding. We and our subsidiaries have incurred and may in the future incur substantial amounts of debt and other obligations that will rank senior to the Series A Preferred Stock. We may incur additional indebtedness and become more highly leveraged in the future, which could harm our financial position and potentially limit our cash available to pay dividends. As a result, we may not have sufficient funds remaining to satisfy our dividend obligations relating to our Series A Preferred Stock if we incur additional indebtedness.

We will establish a segregated account that will be funded at closing with proceeds sufficient to pre-fund four (4) quarterly dividend payments although the payment of such amounts on deposit to holders of the Series A Preferred Stock is subject to compliance with applicable laws and with the foregoing limitations. Additionally, once the funds in the segregated account are exhausted, there can be no assurance that we will have sufficient cash flow from operations to continue such dividend payments. In addition, the amounts on deposit are also assets of our consolidated entity and while we have agreed not to use such amount for any corporate purposes other than payments of dividends on the Series A Preferred Stock, such assets in such account will nonetheless be available to our creditors generally in the event holders of our indebtedness or other obligations arising in the ordinary course of business seek to pursue remedies under bankruptcy or insolvency laws or otherwise. In addition, our Board of Directors may determine that the use of such amount on deposit for other corporate purposes is required pursuant to the exercise of their fiduciary duties to our common stockholders. You should be aware that the pre-funded dividends may not be available to make such payments in the amounts and at the times required under the terms of the Series A Preferred Stock.

Future offerings of debt or senior equity securities may adversely affect the market price of the Series A Preferred Stock. If we decide to issue debt or senior equity securities in the future, it is possible that these securities will be governed by an indenture or other instrument containing covenants restricting our operating flexibility. Additionally, any convertible or exchangeable securities that we issue in the future may have rights, preferences and privileges more favorable than those of the Series A Preferred Stock and may result in dilution to holders of the Series A Preferred Stock. We and, indirectly, our stockholders, will bear the cost of issuing and servicing such securities. Because our decision to issue debt or equity securities in any future offering will depend on market conditions and other factors beyond our control, we cannot predict or estimate the amount, timing or nature of our future offerings. Thus holders of the Series A Preferred Stock will bear the risk of our future offerings reducing the market price of the Series A Preferred Stock and diluting the value of their holdings in us.

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We may issue additional shares of the Series A Preferred Stock and additional series of preferred stock that rank on a parity with the Series A Preferred Stock as to dividend rights, rights upon liquidation or voting rights.

We are allowed to issue additional shares of Series A Preferred Stock and additional series of preferred stock that would rank on a parity with the Series A Preferred Stock as to dividend payments and rights upon our liquidation, dissolution or winding up of our affairs pursuant to our certificate of incorporation and the certificate of designation for the Series A Preferred Stock without any vote of the holders of the Series A Preferred Stock. The issuance of additional shares of Series A Preferred Stock and additional series of parity preferred stock could have the effect of reducing the amounts available to the holders of Series A Preferred Stock issued in this offering upon our liquidation or dissolution or the winding up of our affairs. It also may reduce dividend payments on the Series A Preferred Stock issued in this offering if we do not have sufficient funds to pay dividends on all Series A Preferred Stock outstanding and other classes of stock with equal priority with respect to dividends.

In addition, although holders of the Series A Preferred Stock are entitled to limited voting rights, as described in “Description of Series A Preferred Stock—Voting Rights,” with respect to such matters, the holders of the Series A Preferred Stock will vote separately as a class along with all other outstanding series of our preferred stock that we may issue upon which like voting rights have been conferred and are exercisable. As a result, the voting rights of holders of the Series A Preferred Stock may be significantly diluted, and the holders of such other series of preferred stock that we may issue may be able to control or significantly influence the outcome of any vote.

Future issuances and sales of parity preferred stock, or the perception that such issuances and sales could occur, may cause prevailing market prices for the Series A Preferred Stock and our common stock to decline and may adversely affect our ability to raise additional capital in the financial markets at times and prices favorable to us. Such issuances may also reduce or eliminate our ability to pay dividends on our common stock.

As a holder of Series A Preferred Stock, you will have extremely limited voting rights.

Your voting rights as a holder of Series A Preferred Stock will be limited. Our common stock is the only class of our securities that carries full voting rights. Voting rights for holders of Series A Preferred Stock will exist primarily with respect to the ability to elect (together with the holders of other outstanding series of our preferred stock, or additional series of preferred stock we may issue in the future and upon which similar voting rights have been or are in the future conferred and are exercisable) two additional directors to our Board of Directors in the event that six quarterly dividends (whether or not declared or consecutive) payable on the Series A Preferred Stock are in arrears, and with respect to voting on amendments to our certificate of incorporation or certificate of designation (in some cases voting together with the holders of other outstanding series of our preferred stock as a single class) that materially and adversely affect the rights of the holders of Series A Preferred Stock (and other series of preferred stock, as applicable) or create additional classes or series of our stock that are senior to the Series A Preferred Stock, provided that in any event adequate provision of funds sufficient for redemption has not been made. Other than the limited circumstances described in this prospectus supplement, holders of Series A Preferred Stock will not have any voting rights. See “Description of Series A Preferred Stock—Limited Voting Rights.”

The Series A Preferred Stock has not been rated.

The Series A Preferred Stock has not been rated and may never be rated. It is possible, however, that one or more rating agencies might independently decide to assign a rating to the Series A Preferred Stock or that we may elect to obtain a rating of the Series A Preferred Stock in the future. Furthermore, we may elect to issue other securities for which we may seek to obtain a rating. If any ratings are assigned to the Series A Preferred Stock in the future or if we issue other securities with a rating, such ratings, if they are lower than market expectations or are subsequently lowered or withdrawn, could adversely affect the market for, or the market value of, the Series A Preferred Stock.

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Ratings reflect the views of the issuing rating agency or agencies, and such ratings could at any time be revised downward, placed on negative outlook or withdrawn entirely at the discretion of the issuing rating agency or agencies. Furthermore, a rating is not a recommendation to purchase, sell or hold any particular security, including the Series A Preferred Stock. Ratings do not reflect market prices or the suitability of a security for a particular investor, and any future rating of the Series A Preferred Stock may not reflect all risks related to us and our business, or the structure or market value of the Series A Preferred Stock.

The conversion feature may not adequately compensate you, and the conversion and redemption features of the Series A Preferred Stock may make it more difficult for a party to take over our company and may discourage a party from taking over the Company.

Upon the occurrence of a Delisting Event or Change of Control, holders of the 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 into our common stock (or equivalent value of alternative consideration), and under these circumstances we will also have a special optional redemption right to redeem the Series A Preferred Stock. See “Description of Series A Preferred Stock—Conversion Rights” and “—Special Optional Redemption.” Upon such a conversion, the holders will be limited to a maximum number of shares of our common stock equal to the Share Cap multiplied by the number of shares of Series A Preferred Stock converted. If the Common Stock Price is less than $ (which is approximately 50% of the closing sale price per share of our common stock on December , 2020), subject to adjustment, the holders will receive a maximum of shares of our common stock per share of Series A Preferred Stock, which may result in a holder receiving value that is less than the liquidation preference of the Series A Preferred Stock. In addition, those features of the Series A Preferred Stock may have the effect of inhibiting a third party from making an acquisition proposal for our company or of delaying, deferring or preventing a change of control of the Company under circumstances that otherwise could provide the holders of our common stock and Series A Preferred Stock with the opportunity to realize a premium over the then-current market price or that stockholders may otherwise believe is in their best interests.

The market price of the Series A Preferred Stock could be substantially affected by various factors.

The market price of the Series A Preferred Stock will depend on many factors, which may change from time to time, including, without limitation:

•

prevailing interest rates, increases in which may have an adverse effect on the market price of the Series A Preferred Stock;

•

the annual yield from distributions on the Series A Preferred Stock as compared to yields on other financial instruments;

•

actual or anticipated variations in our operating results from quarter to quarter;

•

actual or anticipated variations in our operating results from the expectations of securities analysts and investors;

•

actual or anticipated variations in our operating results from those of our competitors;

•

sales of equity or other securities by us or our stockholders in the future;

•

changes in expectations as to our future financial performance, including financial estimates by securities analysts and investors;

•

departures of key executives or directors;

•

resignation of our auditors;

•

announcements by us or our competitors of significant contracts, acquisitions, strategic partnerships, financing efforts or capital commitments;

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•

involvement in litigation or governmental investigations or enforcement activity;

•

stock price and volume fluctuations attributable to inconsistent trading volume levels of our shares;

•

general economic and stock market conditions;

•

regulatory or political developments;

•

global pandemics, including the recent COVID-19 pandemic; and

•

terrorist attacks or natural disasters.

Furthermore, the capital markets have in the past experienced and may experience in the future extreme price and volume fluctuations that have affected and continue to affect the market prices of equity securities of many companies. These fluctuations often have been unrelated or disproportionate to the operating performance of those companies. These broad market and industry fluctuations, as well as general economic, political, and market conditions such as recessions, interest rate changes, or international currency fluctuations may negatively impact the market price of the Series A Preferred Stock. If the market price of the Series A Preferred Stock does not exceed the price at which the holders acquired their shares, such holders may not realize a full return on their investment. In the past, companies that have experienced volatility in the market price of their stock have been subject to securities class-action litigation. We may in the future be the target of this type of litigation.

We have broad discretion in the use of the net proceeds of this offering and may not use them effectively.

We intend to use the net proceeds from this offering for general corporate purposes, including, without limitation, funding future acquisitions and investments. However, our management will have broad discretion in the application of the net proceeds from this offering and could spend the proceeds in ways that do not improve our results of operations or enhance the value of our common stock. The failure by management to apply these funds effectively could result in financial losses that could have a material adverse effect on our business and cause the price of our common stock and the Series A Preferred Stock to decline.

Holders of Series A Preferred Stock may be unable to use the dividends-received deduction and may not be eligible for the preferential tax rates applicable to “qualified dividend income.”

Distributions paid to corporate U.S. holders (as defined below in the “Material U.S. Federal Income Tax Consequences” section) on the Series A Preferred Stock may be eligible for the dividends-received deduction, and distributions paid to non-corporate U.S. holders on the Series A Preferred Stock may be subject to tax at the preferential tax rates applicable to “qualified dividend income,” if we have current or accumulated earnings and profits, as determined for U.S. federal income tax purposes. We may not have sufficient current or accumulated earnings and profits during future fiscal years for the distributions on the Series A Preferred Stock to qualify as dividends for U.S. federal income tax purposes. If any distributions on the Series A Preferred Stock with respect to any fiscal year fail to be treated as dividends for U.S. federal income tax purposes, corporate U.S. holders would be unable to use the dividends-received deduction and non-corporate U.S. holders may not be eligible for the preferential tax rates applicable to “qualified dividend income” and generally would be required to reduce their tax basis in the Series A Preferred Stock by the extent to which the distribution is not treated as a dividend. See the “Material U.S. Federal Income Tax Consequences” section for additional information.

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You may be subject to tax if we make or fail to make certain adjustments to the Conversion Rate of the Series A Preferred Stock even though you do not receive a corresponding cash dividend.

The Conversion Rate (as defined in “Description of Series A Preferred Stock—Conversion Rights”) for the Series A Preferred Stock is subject to adjustment in certain circumstances. A failure to adjust (or to adjust adequately) the Conversion Rate after an event that increases your proportionate interest in us could be treated as a deemed taxable dividend to you. If you are a non-U.S. holder (as defined in “Material U.S. Federal Income Tax Considerations”), any deemed dividend may be subject to U.S. federal withholding tax at a 30% rate, or such lower rate as may be specified by an applicable treaty, which may be set off against subsequent payments on the Series A Preferred Stock. In April 2016, the Internal Revenue Service issued new proposed income tax regulations in regard to the taxability of changes in conversion rights that will apply to the Series A Preferred Stock when published in final form and may be applied to us before final publication in certain instances. See “Material U.S. Federal Income Tax Considerations.”

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USE OF PROCEEDS

The net proceeds from the sale of the Series A Preferred Stock in this offering, after deducting the underwriting discount, the structuring fee and other estimated expenses of this offering payable by us, are estimated to be approximately $ million (approximately $ million if the underwriters’ option to purchase up to additional shares of Series A Preferred Stock is exercised in full).

$ of the net proceeds will be deposited at closing in a segregated account, representing an amount sufficient to pre-fund four (4) quarterly dividend payments on the Series A Preferred Stock. We intend to use the net proceeds from this offering to fund the segregated dividend account and the remaining net proceeds for general corporate purposes including, but not limited to, funding future acquisitions of milestone and royalty rights associated with drug development programs with third-party funding. The precise amount, use and timing of the application of such proceeds will depend upon our funding requirements and the availability and cost of other capital. Pending application of the net proceeds as described above, we intend to invest the net proceeds of the offering in short-term, investment-grade, interest-bearing securities and/or savings accounts.

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CAPITALIZATION

The following table sets forth our cash and cash equivalents and capitalization as of September 30, 2020:

•

on an actual basis; and

•

on an as-adjusted basis to give effect to the sale of shares of the Series A Preferred Stock by us in this offering (assuming no exercise of the underwriters’ option to purchase additional shares of Series A Preferred Stock) at the public offering price of $ per share, and after deducting the underwriting discount, the structuring fee and estimated offering expenses payable by us.


	As of September 30, 2020
	Actual			As Adjusted
	(Amounts in thousands, except share count and per share data)
Cash & Cash Equivalents	$	45,725

Total Debt		29,952			29,952
Stockholders’ Equity
Common Stock, $0.0075 par value per share, 277,333,332 shares authorized, 11,022,143 shares issued and outstanding		83			83
Preferred Stock, $0.05 par value per share, 1,000,000 shares authorized, 5,003 shares issued and outstanding (actual), and shares issued and outstanding (as adjusted)		—
Additional paid-in capital		1,241,711
Accumulated deficit		(1,203,752	)		(1,203,752	)

Total Stockholders’ Equity		38,042

Capitalization	$	67,944

The number of shares of our common stock issued and outstanding actual and as adjusted in the table above excludes, as of September 30, 2020:

•

2,002,779 shares of our common stock reserved for issuance upon the exercise of outstanding stock options;

•

19,426 shares of our common stock issuable upon the exercise of outstanding warrants;

•

352,216 shares of our common stock reserved for potential future issuance pursuant to our 2010 Long Term Incentive and Share Award Plan;

•

240,528 shares of our common stock reserved for potential future issuance pursuant to our 2015 Employee Stock Purchase Plan; and

•

5,003,000 shares of our common stock issuable upon the conversion of currently outstanding shares of Series X Preferred Stock.

You should read this table in conjunction with “Use of Proceeds” as well as our “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our consolidated financial statements, including the related notes, incorporated by reference into this prospectus supplement and the accompanying base prospectus from our Annual Report on Form 10-K for the year ended December 31, 2019, and our subsequent Quarterly Reports on Form 10-Q, and incorporated by reference herein and therein.

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DESCRIPTION OF SERIES A PREFERRED STOCK

The following is a summary of the material terms and provisions of the Series A Preferred Stock. The statements below describing our Series A Preferred Stock are in all respects subject to and qualified in their entirety by reference to the applicable provisions of our certificate of incorporation, including the certificate of designation establishing the Series A Preferred Stock, and our bylaws, each of which is available from us as described in the “Where You Can Find More Information” section of this prospectus supplement and is incorporated by reference in this prospectus supplement. This description of the particular terms of the Series A Preferred Stock supplements the description of the general terms and provisions of our preferred stock set forth in the accompanying prospectus under “Description of Capital Stock—Preferred Stock.” For a description of the common stock into which the Series A Preferred Stock is convertible, see “Description of Capital Stock—Common Stock” in the accompanying prospectus.

General

The Company’s current authorized capital stock consists of 277,333,332 shares of common stock, par value $0.0075 per share, and 1,000,000 shares of preferred stock, par value $0.05 per share.

Our Board of Directors may fix the rights, preferences, privileges and restrictions of up to an aggregate of 1,000,000 shares of preferred stock in one or more series and authorize their issuance. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series. The Series A Preferred Stock is being issued pursuant to the certificate of designation that sets forth the terms of a series of preferred stock consisting of up to shares, designated % Series A Cumulative Perpetual Preferred Stock.

The registrar, transfer agent and distributions disbursing agent for the Series A Preferred Stock is American Stock Transfer & Trust Company, LLC.

Ranking

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

Senior to all classes or series of our common stock and to all other equity securities issued by us expressly designated as ranking junior to the Series A Preferred Stock;

Dividends

Holders of Series A Preferred Stock will be entitled to receive, when and as declared by our Board of Directors, out of funds legally available for the payment of dividends, cumulative cash dividends at the rate of % of the

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$25.00 liquidation preference per year (equivalent to $ per year). Dividends on the Series A Preferred Stock will accumulate and be cumulative from, and including, the date of original issue by us of the Series A Preferred Stock. 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, as defined in the certificate of designation, 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 on the amounts so payable for the period from and after that dividend payment date to that next succeeding business day. We refer to each such date as a Dividend Payment Date. The first dividend on the Series A Preferred Stock is scheduled to be paid on or about April 15, 2021, which will be for more than a full quarter and will cover the period from the first date we issue and sell the Series A Preferred Stock through, but not including, April 15, 2021.

Any dividend, including any dividend payable on the Series A Preferred Stock for any partial dividend period, will be computed on the basis of a 360-day year consisting of twelve 30-day months. Dividends are payable to holders of record of Series A Preferred Stock as they appear in the transfer agent’s records at the close of business on the applicable record date, which will be the date that our Board of Directors designates for the determination of such holders that is not more than 30 nor less than 10 days prior to the Dividend Payment Date, which we refer to as a Dividend Payment Record Date.

A segregated account will be funded at closing with proceeds sufficient to pre-fund four (4) quarterly dividend payments, although such funds may only be used for the payment of such dividends to the extent funds are legally available therefor. The segregated account may only be used to pay dividends on the Series A Preferred Stock, when legally permitted, and may not be used for other corporate purposes.

Our Board of Directors will not authorize, pay or set apart for payment by us any dividend on the Series A Preferred Stock at any time that:

•

the terms and provisions of any of our agreements, including any agreement relating to our indebtedness, prohibits such authorization, payment or setting apart for payment;

•

the terms and provisions of any of our agreements, including any agreement relating to our indebtedness, provides that such authorization, payment or setting apart for payment thereof would constitute a breach of, or a default under, such agreement; or

•

the law restricts or prohibits the authorization or payment.

Notwithstanding the foregoing, dividends on the Series A Preferred Stock will accumulate whether or not:

•

the terms and provisions of any of our agreements relating to our indebtedness prohibit such authorization, payment or setting apart for payment;

•

we have earnings;

•

there are funds legally available for the payment of the dividends; and

•

the dividends are authorized.

No interest, or sums in lieu of interest, will accrue on or be payable in respect of any accumulated but unpaid dividend payment or payments on the Series A Preferred Stock, which may be in arrears, and holders of the Series A Preferred Stock will not be entitled to any dividends in excess of the full cumulative dividends described above. Any dividend payment made on the Series A Preferred Stock shall first be credited against the earliest accumulated but unpaid dividends due with respect to those shares.

We will not pay or declare and set apart for payment any dividends (other than a dividend paid in common stock or other stock ranking junior to the Series A Preferred Stock with respect to dividend rights and rights upon our

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voluntary or involuntary liquidation, dissolution or winding up) or declare or make any distribution of cash or other property on common stock or other stock that ranks junior to or on parity with the Series A Preferred Stock with respect to dividend rights and rights upon our voluntary or involuntary liquidation, dissolution or winding up or redeem or otherwise acquire common stock or other stock that ranks junior to or on parity with the Series A Preferred Stock with respect to dividend rights and rights upon our voluntary or involuntary liquidation, dissolution or winding up (except (i) by conversion into or exchange for common stock or other stock ranking junior to the Series A Preferred Stock with respect to dividend rights and rights upon our voluntary or involuntary liquidation, dissolution or winding up, (ii) for the redemption of shares of our stock pursuant to the provisions of our charter relating to the restrictions upon ownership and transfer of our stock and (iii) for a purchase or exchange offer made on the same terms to holders of all outstanding shares of Series A Preferred Stock and any other stock that ranks on parity with the Series A Preferred Stock with respect to dividend rights and rights upon our voluntary or involuntary liquidation, dissolution or winding up), unless we also have either paid or declared and set apart for payment full cumulative dividends on the Series A Preferred Stock for all past dividend periods.

Notwithstanding the foregoing, if we do not either pay or declare and set apart for payment full cumulative dividends on the Series A Preferred Stock and all stock that ranks on parity with the Series A Preferred Stock with respect to dividends, the amount which we have declared will be allocated pro rata to the holders of Series A Preferred Stock and to each equally ranked class or series of stock, so that the amount declared for each share of Series A Preferred Stock and for each share of each equally ranked class or series of stock is proportionate to the accrued and unpaid dividends on those shares. Any dividend payment made on the Series A Preferred Stock will first be credited against the earliest accrued and unpaid dividend.

Liquidation Preference

In the event of any voluntary or involuntary liquidation, dissolution or winding up of our affairs, the holders of shares of Series A Preferred Stock are entitled to be paid out of our assets legally available for distribution to our shareholders a liquidation preference of $25.00 per share, plus an amount equal to any accumulated and unpaid dividends up to the date of payment (whether or not declared), before any distribution or payment may be made to holders of shares of common stock or any other class or series of our equity stock ranking, as to liquidation rights, junior to the Series A Preferred Stock.

If, upon our voluntary or involuntary liquidation, dissolution or winding up, our available assets are insufficient to pay the full amount of the liquidating distributions on all outstanding shares of Series A Preferred Stock and the corresponding amounts payable on all shares of each other class or series of capital stock ranking, as to liquidation rights, on a parity with the Series A Preferred Stock, then the holders of the Series A Preferred Stock and each such other class or series of capital stock ranking, as to liquidation rights, on a parity with the Series A Preferred Stock will share ratably in any distribution of assets in proportion to the full liquidating distributions to which they would otherwise be respectively entitled. Holders of Series A Preferred Stock will be entitled to written notice of any liquidation no fewer than 30 days and no more than 60 days prior to the payment date. After payment of the full amount of the liquidating distributions to which they are entitled, the holders of Series A Preferred Stock will have no right or claim to any of our remaining assets.

Our consolidation or merger with or into any other entity or the sale, lease, transfer or conveyance of all or substantially all of our property or business will not be deemed to constitute our liquidation, dissolution or winding up. The Series A Preferred Stock will rank senior to the common stock as to priority for receiving liquidating distributions and on a parity with any existing and future equity securities which, by their terms, rank on a parity with the Series A Preferred Stock.

Optional Redemption

The Series A Preferred Stock is not redeemable prior to December , 2021, except under the circumstances described below. On and after December , 2021 the first anniversary of December , 2020 to but

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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 , 2022 the second anniversary of December , 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 , 2023, third anniversary of December , 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 , 2024, fourth anniversary of December , 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 , 2025, the fifth anniversary of December , 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 upon the giving of notice, as provided below.

If fewer than all of the outstanding shares of Series A Preferred Stock are to be redeemed, the shares to be redeemed will be determined pro rata or by lot.

In the event we elect to redeem Series A Preferred Stock, notice of redemption will be mailed to each holder of record of Series A Preferred Stock called for redemption at such holder’s address as it appear on our stock transfer records, not less than 30 nor more than 60 days prior to the date fixed for redemption. The notice will notify the holder of the election to redeem the shares and will state at least the following:

•

the date fixed for redemption thereof, which we refer to as the Redemption Date;

•

the redemption price;

•

the number of shares of Series A Preferred Stock a to be redeemed (and, if fewer than all the shares are to be redeemed, the number of shares to be redeemed from such holder);

•

the place(s) where holders may surrender certificates, if any, evidencing the Series A Preferred Stock for payment; and

•

that dividends on the shares of Series A Preferred Stock will cease to accumulate on the date prior to the Redemption Date.

On or after the Redemption Date, each holder of Series A Preferred Stock to be redeemed that holds a certificate other than through DTC book-entry described below must present and surrender the certificates evidencing the shares of Series A Preferred Stock at the place designated in the notice of redemption and shall be entitled to the redemption price and any accumulated and unpaid dividends payable upon the redemption following the surrender.

From and after the Redemption Date (unless we default in payment of the redemption price):

•

all dividends on the shares designated for redemption in the notice will cease to accumulate;

•

all rights of the holders of the shares, except the right to receive the redemption price thereof (including all accumulated and unpaid dividends up to the date prior to the Redemption Date), will cease and terminate; and

•

the shares will not be deemed to be outstanding for any purpose whatsoever.

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or otherwise acquire directly or indirectly any shares of Series A Preferred Stock (except by exchanging it for our capital stock ranking junior to the Series A Preferred Stock as to dividends and upon liquidation); provided, however, that the foregoing shall not prevent the purchase or acquisition by us of shares of Series A Preferred Stock pursuant to a purchase or exchange offer made on the same terms to holders of all outstanding shares of Series A Preferred Stock.

Special Optional Redemption

During any period of time (whether before or after December , 2021) that both (i) the Series A Preferred Stock are no longer listed on Nasdaq, the NYSE or the 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 (which we refer to collectively as a “Delisting Event”), we may, at our option, redeem the Series A Preferred Stock, in whole or in part and within 90 days after the date of the Delisting Event, by paying $25.00 per share, plus any accumulated and unpaid dividends up to, but not including, the date of redemption.

In addition, upon the occurrence of a Change of Control (defined below), we may, at our option, redeem the Series A Preferred Stock, in whole or in part and within 120 days after the first date on which such Change of Control occurred, by paying $25.00 per share, plus any accumulated and unpaid dividends up to, but not including, the date of redemption (other than any dividend with a record date before the applicable redemption date and a payment date after the applicable redemption date, which will be paid on the payment date notwithstanding prior redemption of such shares).

If, prior to the Delisting Event Conversion Date or Change of Control Conversion Date (each as defined below), as applicable, we have provided or provide notice of redemption with respect to the Series A Preferred Stock (whether pursuant to our optional redemption right described above or our special optional redemption), the holders of Series A Preferred Stock will not be permitted to exercise the conversion right described below under “—Conversion Rights” in respect of their shares called for redemption.

We will mail to you, if you are a record holder of the Series A Preferred Stock, a notice of redemption, no fewer than 30 days nor more than 60 days before the redemption date. No failure to give the notice or any defect in the notice or in the mailing of the notice will affect the validity of the proceedings for the redemption of any shares of our Series A Preferred Stock except as to a holder to whom notice was defective or not given. Each notice will state the following:

•

the redemption date;

•

the redemption price;

•

the number of shares of Series A Preferred Stock to be redeemed;

•

the place(s) where holders may surrender certificates, if any, evidencing the Series A Preferred Stock for payment;

•

that the Series A Preferred Stock is being redeemed pursuant to our special optional redemption right in connection with the occurrence of a Delisting Event or Change of Control, as applicable, and a brief description of the transaction or transactions or circumstances constituting such Delisting Event or Change of Control, as applicable;

•

that the holders Series A Preferred Stock to which the notice relates will not be able to convert such shares of Series A Preferred Stock in connection with the Delisting Event or Change of Control, as applicable, and each share of Series A Preferred Stock tendered for conversion that is selected, prior to the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable, for redemption 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; and

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•

that dividends on the Series A Preferred Stock to be redeemed will cease to accumulate on the date prior to the redemption date.

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

•

the acquisition by any person, including any syndicate or group deemed to be a “person” under Section 13(d)(3) of the Exchange Act of beneficial ownership, directly or indirectly, through a purchase, merger or other acquisition transaction or series of purchases, mergers or other acquisition transactions of shares of our company entitling that person to exercise more than 50% of the total voting power of all shares of our company entitled to vote generally in elections of directors (except that such person will be deemed to have beneficial ownership of all securities that such person has the right to acquire, whether such right is currently exercisable or is exercisable only upon the occurrence of a subsequent condition); and

•

following the closing of any transaction referred to in the bullet point above, neither we nor any acquiring or surviving entity (or if, in connection with such transaction shares of our common stock are converted into or exchanged for (in whole or in part) common equity securities of another entity, such other entity) has a class of common securities (or ADRs representing such securities) listed on Nasdaq, the NYSE or the NYSE AMER, or listed or quoted on an exchange or quotation system that is a successor to Nasdaq, the NYSE or the NYSE AMER.

If we redeem fewer than all of the outstanding shares of Series A Preferred Stock, the notice of redemption mailed to each record holder of Series A Preferred Stock will also specify the number of shares of Series A Preferred Stock that we will redeem from such record holder. In this case, we will determine the number of shares of Series A Preferred Stock to be redeemed on a pro rata basis or by lot.

If we have given a notice of redemption and have irrevocably set aside sufficient funds for the redemption for the benefit of the holders of the shares of Series A Preferred Stock called for redemption, then from and after the redemption date, those shares of Series A Preferred Stock will be treated as no longer being outstanding, no further dividends will accumulate on the Series A Preferred Stock and all other rights of the holders of those shares of Series A Preferred Stock will terminate. If any redemption date is not a business day, then the redemption price and accumulated and unpaid dividends, if any, payable upon redemption may be paid on the next business day and no interest, additional dividends or other sums will accumulate on the amount payable for the period from and after that redemption date to that next business day. The holders of those shares of Series A Preferred Stock will retain their right to receive the redemption price for their shares of Series A Preferred Stock (including any accumulated and unpaid dividends up to, but excluding, the redemption date).

The holders of Series A Preferred Stock at the close of business on a dividend record date will be entitled to receive the dividend payable with respect to the Series A Preferred Stock on the corresponding payment date notwithstanding the redemption of the Series A Preferred Stock between such record date and the corresponding payment date or our default in the payment of the dividend due. Except as provided above, we will make no payment or allowance for unpaid dividends, whether or not in arrears, on Series A Preferred Stock to be redeemed.

Unless full cumulative dividends on all shares of Series A Preferred Stock shall have been or contemporaneously are declared and paid or declared and a sum sufficient for the payment thereof has been or contemporaneously is set apart for payment for all past dividend periods, no shares of Series A Preferred Stock shall be redeemed unless all outstanding shares of Series A Preferred Stock are simultaneously redeemed and we shall not purchase or otherwise acquire directly or indirectly any shares of Series A Preferred Stock (except by exchanging it for our capital stock ranking junior to the Series A Preferred Stock as to dividends and upon liquidation); provided, however, that the foregoing shall not prevent the purchase or acquisition by us of shares of Series A Preferred Stock pursuant to a purchase or exchange offer made on the same terms to holders of all shares of Series A Preferred Stock.

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Conversion Rights

Upon the occurrence of a Delisting Event or a Change of Control, as applicable, each holder Series A Preferred Stock will have the right (unless, prior to the Delisting Event Conversion Right or Change of Control Conversion Date, as applicable, we have provided or provide notice of our election to redeem the Series A Preferred Stock as described above under “- Optional Redemption” or “- Special Optional Redemption”) to convert some or all of the shares of Series A Preferred Stock held by such holder (the “Delisting Event Conversion Right” or “Change of Control Conversion Right,” as applicable) 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, or the “Common Stock Conversion Consideration,” equal to the lesser of:

•

the quotient obtained by dividing (1) the sum of the $25.00 per share liquidation preference plus the amount of any accumulated and unpaid dividends up to, but not including, the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable (unless the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable, is after a record date for a Series A Preferred Stock dividend payment and prior to the corresponding Series A Preferred Stock dividend payment date, in which case no additional amount for such accumulated and then remaining unpaid dividend will be included in this sum) by (2) the Common Stock Price (such quotient, the “Conversion Rate”); and

•

(i.e., the Share Cap), subject to certain adjustments described below.

The Share Cap is subject to pro rata adjustments for any share splits (including those effected pursuant to a distribution of shares of our common stock to existing holders of common stock), subdivisions or combinations (in each case, a “Share Split”) with respect to our common stock as follows: the adjusted Share Cap as the result of a Share Split will be the number of shares of our common stock that is equivalent to the product obtained by multiplying (1) the Share Cap in effect immediately prior to such Share Split by (2) a fraction, the numerator of which is the number of shares of our common stock outstanding after giving effect to such Share Split and the denominator of which is the number of shares of our common stock outstanding immediately prior to such Share Split.

In the case of a Delisting Event or Change of Control pursuant to, or in connection with, which our common stock will be converted into cash, securities or other property or assets (including any combination thereof) (the “Alternative Form Consideration”), a holder of Series A Preferred Stock will receive upon conversion of such Series A Preferred Stock the kind and amount of Alternative Form Consideration which such holder would have owned or been entitled to receive upon the Delisting Event or Change of Control, as applicable, had such holder held a number of shares of our common stock equal to the Common Stock Conversion Consideration immediately prior to the effective time of the Delisting Event or Change of Control, as applicable (the “Alternative Conversion Consideration,” and the Common Stock Conversion Consideration or the Alternative Conversion Consideration, as may be applicable to a Delisting Event or Change of Control, as applicable, is referred to as the “Conversion Consideration”).

If the holders of our common stock have the opportunity to elect the form of consideration to be received in the Delisting Event or Change of Control, the Conversion Consideration that the holders of Series A Preferred Stock will receive will be in the form and proportion of the aggregate consideration elected by the holders of our common stock who participate in the determination (based on the weighted average of elections) and will be subject to any limitations to which all holders of our common stock are subject, including, without limitation, pro rata reductions applicable to any portion of the consideration payable in, or in connection with, the Delisting Event or Change of Control, as applicable.

We will not issue fractional shares of common stock upon the conversion of the Series A Preferred Stock. 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 the cash value of such fractional shares in lieu of such fractional shares.

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Within 15 days following the occurrence of a Delisting Event or Change of Control, as applicable, we will provide to holders of Series A Preferred Stock a notice of occurrence of the Delisting Event or Change of Control, as applicable, that describes the resulting Delisting Event Conversion Right or Change of Control Conversion Right, as applicable. This notice will state the following:

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the events constituting the Delisting Event or Change of Control, as applicable;

•

the date of the Delisting Event or Change of Control, as applicable;

•

the last date on which the holders of Series A Preferred Stock may exercise their Delisting Event Conversion Right or Change of Control Conversion Right, as applicable;

•

the method and period for calculating the Common Stock Price;

•

the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable;

•

that if, 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 all or any portion of the Series A Preferred Stock, holders will not be able to convert the Series A Preferred Stock and such shares will be redeemed on the related redemption date, even if such shares have already been tendered for conversion pursuant to the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable;

•

if applicable, the type and amount of Conversion Consideration entitled to be received per share of Series A Preferred Stock;

•

the name and address of the paying agent and the conversion agent;

•

the procedures that the holders of Series A Preferred Stock must follow to exercise the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable; and

•

the last date on which holders of Series A Preferred Stock may withdraw shares surrendered for conversion and the procedures that such holders must follow to effect such a withdrawal.

We will issue a press release setting forth the details of such notice for publication on the Dow Jones & Company, Inc., Business Wire, PR Newswire or Bloomberg Business News (or, if these organizations are not in existence at the time of issuance of the press release, such other news or press organization as is reasonably calculated to broadly disseminate the relevant information to the public), or post notice on our website, in any event prior to the opening of business on the first business day following any date on which we provide the notice described above to the holders of Series A Preferred Stock.

To exercise the Delisting Event Conversion Right or Change of Control Conversion Right, as applicable, each holder of Series A Preferred Stock will be required to deliver, on or before the close of business on the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable, the certificates, if any, evidencing the shares of Series A Preferred Stock to be converted, duly endorsed for transfer, together with a written conversion notice completed, to our transfer agent, or, in the case of shares of Series A Preferred Stock held in global form, comply with the applicable procedures of DTC. The conversion notice must state:

•

the “Delisting Event Conversion Date” or “Change of Control Conversion Date”, as applicable, which will be 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 the notice described above to the holders of the Series A Preferred Stock; and

•

the number of shares of Series A Preferred Stock to be converted.

The “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

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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.

Holders of the Series A Preferred Stock may withdraw any notice of exercise of a Delisting Event Conversion Date or Change of Control Conversion Date, as applicable (in whole or in part), by a written notice of withdrawal delivered to our transfer agent prior to the close of business on the business day prior to the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable. The notice of withdrawal must state:

•

the number of withdrawn shares of Series A Preferred Stock;

•

if certificated shares of Series A Preferred Stock have been issued, the receipt or certificate numbers of the withdrawn shares of Series A Preferred Stock; and

•

the number of shares of Series A Preferred Stock, if any, which remain subject to the conversion notice.

Notwithstanding the foregoing, if the shares of Series A Preferred Stock are held in global form, the conversion notice and/or the notice of withdrawal, as applicable, must comply with applicable procedures of The Depository Trust Company.

Shares of Series A Preferred Stock as to which the Delisting Event Conversion Right or Change of Control Conversion Right, as applicable, has been properly exercised and for which the conversion notice has not been properly withdrawn will be converted into the applicable Conversion Consideration in accordance with the Delisting Event Conversion Right or Change of Control Conversion Right, as applicable, on the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable, 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 such shares of Series A Preferred Stock, whether pursuant to our optional redemption right or our special optional redemption right. If we elect to redeem shares of Series A Preferred Stock that would otherwise be converted into the applicable Conversion Consideration on a Delisting Event Conversion Date or Change of Control Conversion Date, as applicable, such shares of Series A Preferred Stock will not be so converted and the holders of such shares will be entitled to receive on the applicable redemption date $25.00 per share, plus any accumulated and unpaid dividends thereon to, but not including, the redemption date. See “—Optional Redemption” and “—Special Optional Redemption.”

We will deliver the applicable Conversion Consideration no later than the third business day following the Delisting Event Conversion Date or Change of Control Conversion Date, as applicable.

In connection with the exercise of any Delisting Event Conversion Right or Change of Control Conversion Right, as applicable, we will comply with all applicable federal and state securities laws and stock exchange rules in connection with any conversion of Series A Preferred Stock into our common stock.

The Delisting Event Conversion Right or Change of Control Conversion Right, as applicable, may make it more difficult for a third party to acquire us or discourage a party from acquiring us. See “Risk Factors—The

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conversion feature may not adequately compensate you, and the conversion and redemption features of the Series A Preferred Stock may make it more difficult for a party to take over the Company and may discourage a party from taking over the Company.”

The Series A Preferred Stock are not convertible into or exchangeable for any other securities or property, except as provided above.

Limited Voting Rights

Except as described below, holders of Series A Preferred Stock will generally have no voting rights. In any matter in which the Series A Preferred Stock may vote (as expressly provided herein, or as may be required by law), each share of Series A Preferred Stock shall be entitled to one vote.

If dividends on the Series A Preferred Stock are in arrears, whether or not declared, for six or more quarterly periods, whether or not these quarterly periods are consecutive, holders of Series A Preferred Stock and holders of all other classes or series of parity preferred stock with which the holders of Series A Preferred Stock are entitled to vote together as a single class, and are exercisable, voting together as a single class, will be entitled to vote, at a special meeting called by the holders of record of at least 10% of any series of preferred stock as to which dividends are so in arrears or at the next annual meeting of shareholders, for the election of two additional directors to serve on our Board of Directors until all dividend arrearages have been paid. If and when all accumulated dividends on the Series A Preferred Stock for all past dividend periods shall have been paid in full, holders of shares of Series A Preferred Stock shall be divested of the voting rights set forth above (subject to re-vesting in the event of each and every preferred dividend default) and, unless outstanding shares of parity preferred stock remain entitled to vote in the election of preferred stock directors, the term of office of such preferred stock directors so elected will terminate and the number of directors will be reduced accordingly.

In addition, so long as any shares of Series A Preferred Stock remain outstanding, we will not, without the consent or the affirmative vote of the holders of at least two-thirds of the outstanding shares of Series A Preferred Stock and each other class or series of parity preferred stock with which the holders of Series A Preferred Stock are entitled to vote together as a single class on such matter (voting together as a single class):

•

authorize, create or issue, or increase the number of authorized or issued number of shares of, any class or series of stock ranking senior to the Series A Preferred Stock with respect to payment of dividends or the distribution of assets upon our liquidation, dissolution or winding up, or reclassify any of our authorized capital stock into any such shares, or create, authorize or issue any obligation or security convertible into or evidencing the right to purchase any such shares; or

•

amend, alter or repeal the provisions of our charter, including the terms of the Series A Preferred Stock, whether by merger, consolidation, transfer or conveyance of all or substantially all of our assets or otherwise, so as to materially and adversely affect the rights, preferences, privileges or voting powers of the Series A Preferred Stock,

except that, with respect to the occurrence of any of the events described in the second bullet point immediately above, so long as the Series A Preferred Stock remains outstanding with the terms of the Series A Preferred Stock materially unchanged, taking into account that, upon the occurrence of an event described in the second bullet point above, we may not be the surviving entity and the surviving entity may not be a corporation, the occurrence of such event will not be deemed to materially and adversely affect the rights, preferences, privileges or voting powers of the Series A Preferred Stock, and in such case such holders shall not have any voting rights with respect to the events described in the second bullet point immediately above. Furthermore, if holders of shares of the Series A Preferred Stock receive the greater of the full trading price of the Series A Preferred Stock on the date of an event described in the second bullet point immediately above or the $25.00 per share of the Series A Preferred Stock liquidation preference plus all accrued and unpaid dividends thereon pursuant to the occurrence of any of the events described in the second bullet point immediately above, then such holders shall

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not have any voting rights with respect to the events described in the second bullet point immediately above. If any event described in the second bullet point above would materially and adversely affect the rights, preferences, privileges or voting powers of the Series A Preferred Stock disproportionately relative to any other class or series of parity preferred stock, the affirmative vote of the holders of at least two-thirds of the outstanding shares of the Series A Preferred Stock, voting as a separate class, will also be required.

The following actions are not deemed to materially and adversely affect the rights, preferences, powers or privileges of the Series A Preferred Stock:

•

any increase in the amount of our authorized common stock or preferred stock or the creation or issuance of equity securities of any class or series ranking, as to dividends or liquidation preference, on a parity with, or junior to, the Series A Preferred Stock; or

•

the amendment, alteration or repeal or change of any provision of our articles of incorporation, including the certificate of designation establishing the Series A Preferred Stock, as a result of a merger, consolidation, reorganization or other business combination, if the Series A Preferred Stock (or shares into which the Series A Preferred Stock have been converted in any successor entity to us) remain outstanding with the terms thereof materially unchanged.

No Maturity, Sinking Fund or Mandatory Redemption

The Series A Preferred Stock has no maturity date and we are not required to redeem the Series A Preferred Stock at any time. Accordingly, the Series A Preferred Stock will remain outstanding indefinitely, unless we decide, at our option, to exercise our redemption right or, under circumstances where the holders of Series A Preferred Stock have a conversion right, such holders convert the Series A Preferred Stock into our common stock. The Series A Preferred Stock is not subject to any sinking fund.

Listing

No current market exists for the Series A Preferred Stock. We have applied to list the Series A Preferred Stock on Nasdaq under the symbol “XOMAP.” If this application is approved, we expect trading in the Series A Preferred Stock to commence within 30 days of the initial delivery of the Series A Preferred Stock to the underwriters.

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BOOK-ENTRY, DELIVERY AND FORM

The Series A Preferred Stock will be issued in fully registered form in the name of Cede & Co., as nominee of The Depository Trust Company (“DTC”). One or more fully registered global securities will be issued representing in the aggregate the total number of the share of Series A Preferred Stock. Such global securities will be deposited with or on behalf of DTC and may not be transferred except as a whole by DTC to a nominee of DTC or by a nominee of DTC to DTC or another nominee of DTC or by DTC or any nominee to a successor of DTC or a nominee of such successor.

So long as DTC, or its nominee, is the registered owner of a global security, DTC or such nominee, as the case may be, will be considered the sole owner or holder of the Series A Preferred Stock represented by such global security for all purposes under the instruments governing the rights and obligations of holders of the Series A Preferred Stock. Except as set forth in the accompanying prospectus, owners of beneficial interests in a global security will not be entitled to have the shares of Series A Preferred Stock represented by such global security registered in their names, will not receive or be entitled to receive physical delivery of such shares of Series A Preferred Stock in definitive form and will not be considered the owners or holders thereof. Accordingly, each person owning a beneficial interest in a global security must rely on the procedures of DTC for such global security and, if such person is not a participant in DTC (as described below), on the procedures of the participant through which such person owns its interest, to exercise any rights of a holder.

As long as the shares of Series A Preferred Stock are represented by the global securities, we will pay dividends, if any, on the Series A Preferred Stock to or as directed by DTC as the registered holder of the global securities. Payments to DTC will be in immediately available funds by wire transfer. DTC will credit the relevant accounts of their participants on the applicable date. Neither we nor EQ Shareowner Services will be responsible for making any payments to participants or customers of participants or for maintaining any records relating to the holdings of participants and their customers, and each person owning a beneficial interest will have to rely on the procedures of the depositary and its participants.

DTC has advised us that it is a limited-purpose trust company organized under the New York Banking Law, a “banking organization” within the meaning of the New York Banking Law, a member of the Federal Reserve System, a “clearing corporation” within the meaning of the New York Uniform Commercial Code, and a “clearing agency” registered pursuant to the provisions of Section 17A of the Securities Exchange Act of 1934, as amended. DTC holds securities deposited with it by its participants and facilitates the settlement of transactions among its participants in such securities through electronic computerized book-entry changes in accounts of the participants, thereby eliminating the need for physical movement of securities certificates. DTC’s participants include securities brokers and dealers, banks, trust companies, clearing corporations and certain other organizations, some of whom (and/or their representatives) own DTC. Access to DTC’s book-entry system is also available to others, such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with a participant, either directly or indirectly. According to DTC, the foregoing information with respect to DTC has been provided to the financial community for informational purposes only and is not intended to serve as a representation, warranty or contract modification of any kind.

Settlement

Investors in the Series A Preferred Stock will be required to make their initial payment for the Series A Preferred Stock in immediately available funds. Secondary market trading between DTC participants will occur in the ordinary way in accordance with DTC rules and will be settled in immediately available funds.

The information in this section concerning DTC and DTC’s book-entry system has been obtained from sources that we believe to be reliable (including DTC), but we take no responsibility for the accuracy thereof.

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Neither we nor the underwriters will have any responsibility or obligation to participants, or the persons for whom they act as nominees, with respect to the accuracy of the records of DTC, its nominee or any participant with respect to any ownership interest in the shares of Series A Preferred Stock or payments to, or the providing of notice to participants or beneficial owners.

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MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS

The following summary describes certain material U.S. federal income tax consequences of the acquisition, ownership, and disposition of our Series A Preferred Stock acquired in this offering. This discussion is not a complete analysis of all potential U.S. federal income tax consequences relating thereto, and does not address foreign, state, and local consequences that may be relevant to stockholders in light of their particular circumstances, nor does it address U.S. federal tax consequences (such as gift and estate taxes) other than income taxes. This discussion is limited to stockholders that hold our Series A Preferred Stock as a “capital asset” within the meaning of Section 1221 of the Code (generally, property held for investment). This discussion does not address all U.S. federal income tax consequences relevant to a stockholder’s particular circumstances, including the impact of the alternative minimum tax, the special tax accounting rules under Section 451(b) of the Code, and the Medicare contribution tax on net investment income. Special rules different from those described below may apply to certain stockholders that are subject to special treatment under the Internal Revenue Code of 1986, as amended (the “Code”), such as financial institutions, insurance companies, tax-exempt organizations, broker-dealers and traders in securities, U.S. expatriates, “controlled foreign corporations,” “passive foreign investment companies,” corporations that accumulate earnings to avoid U.S. federal income tax, corporations organized outside of the United States, any state thereof or the District of Columbia that are nonetheless treated as U.S. taxpayers for U.S. federal income tax purposes, persons that hold our Series A Preferred Stock as part of a “straddle,” “hedge,” “conversion transaction,” “synthetic security” or integrated investment or other risk reduction strategy, persons who acquire our Series A Preferred Stock through the exercise of an option or otherwise as compensation, “qualified foreign pension funds” as defined in Section 897(l)(2) of the Code and entities all of the interests of which are held by qualified foreign pension funds, partnerships and other pass-through entities or arrangements, and investors in such pass-through entities or arrangements. Such stockholders are urged to consult their own tax advisors to determine the U.S. federal, state, local, and other tax consequences that may be relevant to them. Furthermore, the discussion below is based upon the provisions of the Code, and Treasury Regulations, rulings, and judicial decisions thereunder as of the date hereof, and such authorities may be repealed, revoked, or modified, perhaps retroactively, so as to result in U.S. federal income tax consequences different from those discussed below. We have not requested a ruling from the U.S. Internal Revenue Service (the “IRS”) with respect to the statements made and the conclusions reached in the following summary, and there can be no assurance that the IRS will agree with such statements and conclusions.

This discussion is for informational purposes only and is not tax advice. Persons considering the purchase of our Series A Preferred Stock pursuant to this offering should consult their own tax advisors concerning the U.S. federal income, estate, and other tax consequences of acquiring, owning, and disposing of our Series A Preferred Stock in light of their particular situations as well as any consequences arising under the laws of any other taxing jurisdiction, including any state, local, or foreign tax consequences.

A “U.S. Holder” means a beneficial owner of our Series A Preferred Stock that is for U.S. federal income tax purposes any of the following:

an individual who is a citizen or resident of the United States;

a corporation or other entity treated as a corporation for U.S. federal income tax purposes created or organized in or under the laws of the United States, any state thereof, or the District of Columbia;

an estate the income of which is subject to U.S. federal income taxation regardless of its source; or

a trust if it (1) is subject to the primary supervision of a court within the United States and one or more U.S. persons have the authority to control all substantial decisions of the trust or (2) has a valid election in effect under applicable U.S. Treasury Regulations to be treated as a U.S. person.

For the purposes of this discussion, a “Non-U.S. Holder” is, for U.S. federal income tax purposes, a beneficial owner of Series A Preferred Stock that is neither a U.S. Holder, nor a partnership (or other entity treated as a partnership for U.S. federal income tax purposes regardless of its place of organization or formation).

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Tax Considerations for U.S. Holders

Distributions.

Distributions with respect to the Series A Preferred Stock will be taxable as dividend income to the extent paid out of our current and accumulated earnings and profits as determined for U.S. federal income tax purposes. To the extent that the amount of a distribution with respect to the Series A Preferred Stock exceeds our current and accumulated earnings and profits, such distribution will be treated first as a tax-free return of capital to the extent of the U.S. Holder’s adjusted tax basis in such Series A Preferred Stock, and thereafter as capital gain.

Distributions with respect to the Series A Preferred Stock taxable as dividends for U.S. federal income tax purposes paid to a corporate U.S. Holder will generally qualify for a 50% dividends-received deduction, subject to various limitations. Corporate U.S. Holders should consult their tax advisors regarding the holding period and other requirements that must be satisfied in order to qualify for the dividends-received deduction in their particular circumstances. Distributions with respect to the Series A Preferred Stock taxable as dividends for U.S. federal income tax purposes paid to a noncorporate U.S. Holder will generally represent “qualified dividend income.” Qualified dividend income is taxable at preferential rates applicable to long-term capital gains, provided that certain holding period requirements are met and certain other conditions are satisfied. A U.S. holder should consult its own tax advisors regarding the availability of the reduced tax rate applicable to qualified dividend income and the dividends-received deduction in light of its particular circumstances.

Extraordinary Dividends

Dividends that exceed certain thresholds in relation to a U.S. Holder’s tax basis in our Series A Preferred Stock could be characterized as “extraordinary dividends” under the Code. A corporate U.S. Holder that has held our Series A Preferred Stock for two years or less before the dividend announcement date and that receives an extraordinary dividend will generally be required to reduce its tax basis in the stock (but not below zero) with respect to which such dividend was made by the “nontaxed portion” of such dividend, which equals (i) the amount of such dividend over (ii) the portion of such dividend includible in gross income, reduced by any dividends received deduction allowable with respect to such dividend. If the amount of the reduction exceeds the U.S. Holder’s tax basis in such stock, the excess is taxable as capital gain realized on the sale or other disposition of the Series A Preferred Stock.

Holder’s Conversion Option in connection with a Change of Control or Delisting Event.

In the event of a U.S. Holder’s conversion of Series A Preferred Stock in connection with a Change of Control, Delisting Event or otherwise, the tax consequences of such conversion will depend, in part, upon the facts underlying the transaction in which the conversion occurs. A U.S. holder should consult its tax advisor regarding the tax consequences of the conversion of Series A Preferred Stock.

Constructive Distributions.

The conversion price of our Series A Preferred Stock is subject to adjustment under certain circumstances. Additionally, because the Series A Preferred Stock may be redeemed at a premium under certain circumstances, the Series A Preferred Stock may be treated as issued with redemption premium. In either such circumstances, U.S. Holders of our Series A Preferred Stock may be deemed to have received a distribution if the adjustment (or failure to make an adjustment), or if the redemption premium, has the effect of increasing the proportionate interest of the U.S. holder in our assets or earnings and profits. If such adjustments are made, U.S. holders will be deemed to have received constructive distributions from us even though they may not receive any cash or property. Any deemed distributions will be taxable as a dividend, return of capital, or capital gain as described in “Distributions” above. However, U.S. Holders should consult with their own tax advisors as to whether a constructive dividend deemed paid to a non-corporate U.S. Holder would be eligible for the preferential rates of U.S. federal income tax applicable in respect of certain dividends received. It is also unclear whether corporate

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U.S. Holders would be entitled to claim the dividends received deduction with respect to any such constructive dividends. Because a constructive dividend deemed received by a U.S. Holder would not give rise to any cash from which any applicable withholding could be satisfied, if backup withholding is paid on behalf of a U.S. Holder (because such U.S. Holder failed to establish an exemption from backup withholding), such backup withholding may be withheld, in certain circumstances, from payments on the Series A Preferred Stock. Generally, a U.S. holder’s adjusted tax basis in the Series A Preferred Stock will be increased to the extent any such constructive distribution is treated as a dividend. U.S. Holders should consult their tax advisors on the impact a constructive distribution may have on their holding period in the Series A Preferred Stock. Adjustments to the conversion price made pursuant to a bona fide reasonable adjustment formula which has the effect of preventing dilution of the interest of the holders of shares of our Series A Preferred Stock generally will not be considered to result in a constructive dividend distribution.

The IRS proposed regulations addressing the amount and timing of deemed distributions. If adopted as proposed, the regulations would generally provide that: (i) the amount of a constructive distribution is the excess of the fair market value of the right to acquire common stock immediately after the conversion rate adjustment over the fair market value of the right to acquire common stock (determined immediately after conversion rate adjustment) without the adjustment, and (ii) the constructive distribution occurs at the earlier of the date the adjustment occurs under the terms of the Series A Preferred Stock and the date of the actual distribution of cash or property that results in the constructive distribution. The final regulations will be effective for deemed distributions occurring on or after the date of adoption, but holders of Series A Preferred Stock and withholding agents may rely on them prior to that date under certain circumstances.

Sale, Exchange, or Certain Other Taxable Dispositions of the Series A Preferred Stock.

A U.S. Holder will generally recognize capital gain or loss on a sale or exchange or other taxable disposition (other than certain redemptions described under “Redemptions of the Series A Preferred Stock”) of Series A Preferred Stock equal to the difference, if any, between the amount realized upon the sale or exchange and such U.S. Holder’s adjusted tax basis in the Series A Preferred Stock sold or exchanged. Such capital gain or loss will be long-term capital gain or loss if the U.S. Holder’s holding period for the Series A Preferred Stock sold or exchanged is more than one year. Long-term capital gains of noncorporate taxpayers are generally taxed at preferential rates. The deductibility of capital losses is subject to limitations.

Redemptions of the Series A Preferred Stock.

Whether a payment made in redemption of the Series A Preferred Stock will be treated as a dividend or as a payment in exchange for the Series A Preferred Stock can only be determined on the basis of the particular facts as to each U.S. Holder of the Series A Preferred Stock at the time of redemption.

In general, a U.S. Holder of the Series A Preferred Stock will recognize capital gain or loss measured by the difference between the amount received by the U.S. Holder for such Series A Preferred Stock upon the redemption and such U.S. Holder’s adjusted tax basis in the Series A Preferred Stock redeemed if such redemption is considered to:

•

result in a complete termination of the U.S. Holder’s stock interest in us under Section 302(b)(3) of the Code;

•

be substantially disproportionate with respect to the U.S. Holder under Section 302(b)(2) of the Code;

•

be not essentially equivalent to a dividend with respect to the U.S. Holder under Section 302(b)(1) of the Code; or

•

be a redemption of stock held by a shareholder who is not a corporation and where such redemption results in a partial liquidation of us under Section 302(b)(4) of the Code.

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In applying these tests, there must be taken into account not only the Series A Preferred Stock being redeemed, but also such U.S. Holder’s ownership of other classes and series of our capital stock and any options (including stock purchase rights) to acquire any of the foregoing. A U.S. Holder of the Series A Preferred Stock also must take into account any such securities (including options) that are considered to be owned by such U.S. Holder by reason of the constructive ownership rules set forth in Sections 302(c) and 318 of the Code.

If the redemption does not meet any of the tests described above, then the redemption proceeds received from the Series A Preferred Stock will be treated as a distribution on our shares and will be taxable as described under the caption “Distributions” above. If a redemption of the Series A Preferred Stock is treated as a distribution that is taxable as a dividend, U.S. Holders are urged to consult their own tax advisors regarding the allocation of their tax basis in the redeemed and remaining Series A Preferred Stock.

Tax Considerations for Non-U.S. Holders

Distributions.

Distributions, if any, made on our Series A Preferred Stock to a Non-U.S. Holder to the extent made out of our current and accumulated earnings and profits (as determined under U.S. federal income tax principles) generally will constitute dividends for U.S. tax purposes and will be subject to withholding tax at a 30% rate or such lower rate as may be specified by an applicable income tax treaty, subject to the discussions below regarding effectively connected income, backup withholding, and foreign accounts. To obtain a reduced rate of withholding under a treaty, a Non-U.S. Holder generally will be required to provide us with a properly executed IRS Form W-8BEN (in the case of individuals) or IRS Form W-8BEN-E (in the case of entities), or other appropriate form, certifying the Non-U.S. Holder’s entitlement to benefits under that treaty. This certification must be provided to us and/or our paying agent prior to the payment of dividends and must be updated periodically. If a Non-U.S. Holder is eligible for a reduced rate of U.S. federal withholding tax under an income tax treaty and such Non-U.S. Holder does not timely file the required certification, such Non-U.S. Holder may be able to obtain a refund or credit of any excess amounts withheld by timely filing an appropriate claim for a refund with the IRS.

We generally are not required to withhold tax on dividends paid to a Non-U.S. Holder that are effectively connected with the Non-U.S. Holder’s conduct of a trade or business within the United States (and, if required by an applicable income tax treaty, are attributable to a permanent establishment or fixed base that such holder maintains in the United States) if a properly executed IRS Form W-8ECI, stating that the dividends are so connected, is furnished to us (or, if stock is held through a financial institution or other agent, to such agent). In general, such effectively connected dividends will be subject to U.S. federal income tax, on a net income basis at the regular rates applicable to U.S. residents. A corporate Non-U.S. Holder receiving effectively connected dividends may also be subject to an additional “branch profits tax,” which is imposed, under certain circumstances, at a rate of 30% (or such lower rate as may be specified by an applicable treaty) on the corporate Non-U.S. Holder’s effectively connected earnings and profits, subject to certain adjustments. Non-U.S. Holders should consult their tax advisors regarding any applicable income tax treaties that may provide for different rules.

To the extent distributions on our Series A Preferred Stock, if any, exceed our current and accumulated earnings and profits, they will first reduce the Non-U.S. Holder’s adjusted basis in our Series A Preferred Stock, but not below zero, and then will be treated as gain to the extent of any excess amount distributed, and taxed in the same manner as gain realized from a sale or other disposition of Series A Preferred Stock as described below under “Sale, Exchange or Certain Other Taxable Dispositions of the Series A Preferred Stock.”

Holder’s Conversion Option in connection with a Change of Control or Delisting Event.

In the event of a Non-U.S. Holder’s conversion of Series A Preferred Stock in connection with a Change of Control, Delisting Event or otherwise, the tax consequences of such conversion will depend, in part, upon the facts underlying the transaction in which the conversion occurs. A Non-U.S. Holder should consult its tax advisor regarding the tax consequences of the conversion of Series A Preferred Stock.

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Constructive Distributions.

As described above under “Tax Considerations for U.S. Holders—Constructive Distributions,” adjustments in the conversion price (or failures to adjust the conversion price), or possible redemption premium, that result in an increase in the proportionate interest of a Non-U.S. Holder in our assets or earnings and profits could result in deemed distributions to the Non-U.S. holder that are taxed as described above under “Distributions.”

Sale, Exchange, or Certain Other Taxable Dispositions of the Series A Preferred Stock.

Subject to the discussions below regarding backup withholding and foreign accounts, a Non-U.S. Holder generally will not be subject to U.S. federal income tax with respect to gain realized on a sale or other taxable disposition of our Series A Preferred Stock unless (a) the gain is effectively connected with a trade or business of such holder in the United States (and, if required by an applicable income tax treaty, is attributable to a permanent establishment or fixed base that such holder maintains in the United States), (b) the Non-U.S. Holder is a nonresident alien individual and is present in the United States for 183 or more days in the taxable year of the disposition and certain other conditions are met, or (c) we are or have been a “United States real property holding corporation” within the meaning of Code Section 897(c)(2) at any time within the shorter of the five-year period preceding such disposition or such holder’s holding period in our Series A Preferred Stock. In general, we would be a United States real property holding corporation if our interests in U.S. real property comprise (by fair market value) at least half of our worldwide real property interests and our other assets used or held for use in a trade or business. We believe that we are not, and do not anticipate becoming, a United States real property holding corporation; however, there can be no assurance that we will not become one in the future.

Non-U.S. Holders described in (a) above will be required to pay tax on the net gain derived from the sale at regular U.S. federal income tax rates, and corporate Non-U.S. Holders described in (a) above may be subject to the additional branch profits tax on such gain at a 30% rate or such lower rate as may be specified by an applicable income tax treaty. Gain described in (b) above will be subject to U.S. federal income tax at a flat 30% rate or such lower rate as may be specified by an applicable income tax treaty, which gain may be offset by certain U.S.-source capital losses (even though a Non-U.S. Holder is not considered a resident of the United States), provided that the Non-U.S. Holder has timely filed U.S. federal income tax returns with respect to such losses.

As discussed above under “Tax Considerations for U.S. Holders—Redemptions of the Series A Preferred Stock,” an amount paid to a Non-U.S. Holder in connection with a redemption of the Series A Preferred Stock may, under certain circumstances, be treated as a dividend. In that case, the payment would be subject to the rules for dividends described above under “Non-U.S. Holders—Distributions.”

•

Information Reporting Requirements and Backup Withholding

Generally, we must report information to the IRS with respect to any distributions we pay on our Series A Preferred Stock (even if the payments are exempt from withholding), including the amount of any such distributions, the name and address of the recipient, and the amount, if any, of tax withheld. A similar report is sent to the holder to whom any such distributions are paid. Pursuant to tax treaties or certain other agreements, the IRS may make its reports available to tax authorities in the recipient’s country of residence.

Distributions paid by us (or our paying agents) to a Non-U.S. Holder may also be subject to U.S. backup withholding. U.S. backup withholding generally will not apply to a Non-U.S. Holder who provides a properly executed IRS Form W-8BEN, IRS Form W-8BEN-E, or IRS Form W-ECI, or otherwise establishes an exemption. Notwithstanding the foregoing, backup withholding may apply if the payor has actual knowledge, or reason to know, that the holder is a U.S. person who is not an exempt recipient.

U.S. information reporting and backup withholding requirements generally will apply to the proceeds of a disposition of our Series A Preferred Stock effected by or through a U.S. office of any broker, U.S. or foreign,

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except that information reporting and such requirements may be avoided if the holder provides a properly executed IRS Form W-8BEN or IRS Form W-8BEN-E or otherwise meets documentary evidence requirements for establishing non-U.S. person status or otherwise establishes an exemption. Generally, U.S. information reporting and backup withholding requirements will not apply to a payment of disposition proceeds to a Non-U.S. Holder where the transaction is effected outside the United States through a non-U.S. office of a non-U.S. broker. Information reporting and backup withholding requirements may, however, apply to a payment of disposition proceeds if the broker has actual knowledge, or reason to know, that the holder is, in fact, a U.S. person. For information reporting purposes, certain brokers with substantial U.S. ownership or operations will generally be treated in a manner similar to U.S. brokers.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be credited against the tax liability of persons subject to backup withholding, provided that the required information is timely furnished to the IRS.

•

Foreign Accounts

Sections 1471 through 1474 of the Code (commonly referred to as FATCA) impose a U.S. federal withholding tax of 30% on certain payments to a foreign financial institution (as specifically defined by applicable rules) unless such institution enters into an agreement with the U.S. government to withhold on certain payments and to collect and provide to the U.S. tax authorities substantial information regarding U.S. account holders of such institution (which includes certain equity holders of such institution, as well as certain account holders that are foreign entities with U.S. owners). FATCA also generally imposes a federal withholding tax of 30% on certain payments to a non-financial foreign entity unless such entity provides the withholding agent with either a certification that it does not have any substantial direct or indirect U.S. owners or provides information regarding substantial direct and indirect U.S. owners of the entity. An intergovernmental agreement between the United States and an applicable foreign country may modify those requirements. The withholding tax described above will not apply if the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from the rules.

FATCA withholding currently applies to payments of dividends, if any, on our Series A Preferred Stock and, subject to the proposed Treasury Regulations described in this paragraph, generally also would apply to payments of gross proceeds from the sale or other disposition of our Series A Preferred Stock. The U.S. Treasury Department released proposed regulations which, if finalized in their present form, would eliminate the federal withholding tax of 30% applicable to the gross proceeds of a disposition of our Series A Preferred Stock. In its preamble to such proposed regulations, the U.S. Treasury Department stated that taxpayers may generally rely on the proposed regulations until final regulations are issued. Non-U.S. holders are encouraged to consult with their own tax advisors regarding the possible implications of FATCA on their investment in our Series A Preferred Stock.

EACH PROSPECTIVE INVESTOR SHOULD CONSULT ITS OWN TAX ADVISOR REGARDING THE TAX CONSEQUENCES OF PURCHASING, HOLDING, AND DISPOSING OF OUR SERIES A PREFERRED STOCK, INCLUDING THE CONSEQUENCES OF ANY RECENT OR PROPOSED CHANGE IN APPLICABLE LAW.

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UNDERWRITING

B. Riley Securities, Inc. is acting as representative of each of the underwriters named below. Subject to the terms and conditions set forth in an underwriting agreement among us and the underwriters, we have agreed to sell to the underwriters, and each of the underwriters has agreed to purchase from us, the number of shares of our Series A Preferred Stock set forth opposite its name below.


Name		Number of Shares
B. Riley Securities, Inc.
Aegis Capital Corp.
A.G.P.
Boenning & Scattergood, Inc.
Ladenburg Thalmann & Co. Inc.
National Securities Corporation
Northland Securities, Inc.
William Blair & Company

Total

The underwriting agreement provides that the obligations of the underwriters to pay for and accept delivery of the Series A Preferred Stock offered by this prospectus supplement are subject to the approval of certain legal matters by their counsel and to other conditions, including the absence of any material adverse change in our business and the receipt of customary legal opinions, letters and certificates. The underwriters are committed to take and pay for all of the shares of Series A Preferred Stock being offered, if any are taken, other than the shares covered by the option described below unless and until this option is exercised. If an underwriter defaults, the underwriting agreement provides that the purchase commitments of the non-defaulting underwriters may be increased or the underwriting agreement may be terminated.

Commissions and Expenses

The representative has advised us that the underwriters propose initially to offer the Series A Preferred Stock to the public at the public offering price set forth on the cover page of this prospectus supplement and to securities dealers at the public offering price less a concession not in excess of $ per share. The shares of Series A Preferred Stock are offered by the underwriters as stated in this prospectus supplement, subject to receipt and acceptance and subject to their right to reject any order in whole or in part. If all the shares are not sold at the public offering price, the underwriters may change the offering price and selling terms.

The following table shows the per share and total public offering price, underwriting discount and proceeds before expenses to us and the structuring fee. The amounts are shown assuming both no exercise and full exercise of the underwriters’ option to purchase up to additional shares of Series A Preferred Stock.

Per Share

No
Exercise

Full
Exercise

Public offering price

Underwriting discount and commissions

Proceeds to us, before expenses

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The estimated offering expenses payable by us, exclusive of the underwriting discounts and commissions, are approximately $ . We have also agreed to reimburse the Underwriters up to $75,000 of the Underwriters’ actual expenses, including legal expenses, incurred by the Underwriters in connection with this offering. We have also agreed to pay B. Riley Securities, Inc. a structuring fee of $ for evaluation, analysis and structuring of the Series A Preferred Stock.

Option to Purchase Additional Shares

We have granted to the underwriters an option to purchase up to an additional shares of Series A Preferred Stock at the public offering price, less the underwriting discount. This option is exercisable for a period of 30 days. To the extent that the underwriters exercise this option, the underwriters will purchase additional shares from us in approximately the same proportion as shown in the table above.

Lock-Up Agreements

We have agreed, subject to limited exceptions, for a period of 60 days from the date of this prospectus supplement, not to offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Series A Preferred Stock or any securities convertible into or exchangeable or exercisable for shares of Series A Preferred Stock.

Indemnification

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act and liabilities arising from breaches of representations and warranties contained in the underwriting agreement, or to contribute to payments that the underwriters may be required to make in respect of those liabilities.

Price Stabilization, Short Positions and Penalty Bids

In connection with the offering, the underwriters may engage in transactions that stabilize, maintain or otherwise affect the price of our Series A Preferred Stock. These transactions may include short sales, stabilizing transactions, and purchases to cover positions created by short sales. Short sales involve the sale by the underwriters of a greater number of shares than it is required to purchase in the offering, and a short position represents the amount of such sales that have not been covered by subsequent purchases. The underwriters must cover any such short position by purchasing shares in the open market. A short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of our Series A Preferred Stock in the open market after pricing that could adversely affect investors who purchase in the offering. Stabilizing transactions consist of various bids for or purchases of our Series A Preferred Stock made by the underwriters in the open market prior to the closing of the offering. Purchases to cover a short position and stabilizing transactions, as well as other purchases by an underwriter for its own account, may have the effect of preventing or retarding a decline in the market price of our Series A Preferred Stock, and may stabilize, maintain, or otherwise affect the market price of our Series A Preferred Stock. As a result, the price of our Series A Preferred Stock may be higher than the price that otherwise might exist in the open market. The underwriters are not required to engage in these activities and may end any of these activities at any time. These transactions may be effected on Nasdaq, in the over-the-counter market, or otherwise.

In connection with the offering, the underwriters may engage in passive market making transactions in the Series A Preferred Stock on Nasdaq in accordance with Rule 103 of Regulation M under the Exchange Act during the period before the commencement of offers or sales of the Series A Preferred Stock and extending through the completion of distribution. A passive market maker must display its bids at a price not in excess of the highest independent bid of the security. However, if all independent bids are lowered below the passive market maker’s

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bid that bid must be lowered when specified purchase limits are exceeded. If passive market making is commenced, it may be discontinued at any time.

Conflicts of Interest

The underwriters and their respective affiliates are full-service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. The underwriters and certain of their affiliates have provided from time to time, and may provide in the future, investment and commercial banking and financial advisory services to us and our affiliates in the ordinary course of business, for which they have received and may continue to receive customary fees and commissions. In the ordinary course of their various business activities, the underwriters and their respective affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own accounts and for the accounts of their customers, and such investment and securities activities may involve securities and/or instruments of ours. The underwriters and their respective affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or instruments and may at any time hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

Electronic Offer, Sale and Distribution of Series A Preferred Stock

A prospectus in electronic format may be made available on the websites maintained by one or more of the underwriters participating in this offering and one or more of underwriters participating in this offering may distribute prospectuses electronically. The representative may agree to allocate a number of shares to underwriters for sale to their online brokerage account holders. Internet distributions will be allocated by the underwriters that will make internet distributions on the same basis as other allocations. Other than the prospectus in electronic format, the information on these websites is not part of this prospectus supplement, the accompanying prospectus or the registration statement of which the accompanying prospectus forms a part, has not been approved or endorsed by us or any underwriter in its capacity as underwriter, and should not be relied upon by investors.

Listing

We have applied to list the Series A Preferred Stock on Nasdaq under the symbol “XOMAP.” If this application is approved, we expect trading in the Series A Preferred Stock to commence within 30 days of the initial delivery of the Series A Preferred Stock to the underwriters. The underwriters have advised us that they intend to make a market in the Series A Preferred Stock prior to the commencement of trading on Nasdaq. The underwriters will have no obligation to make a market in the Series A Preferred Stock, however, and may cease market making activities, if commenced, at any time.

NOTICE TO INVESTORS

Australia

This prospectus is not a disclosure document for the purposes of Australia’s Corporations Act 2001 (Cth) of Australia (the “Corporations Act”), has not been lodged with the Australian Securities & Investments Commission and is only directed to the categories of exempt persons set out below. Accordingly, if you receive this prospectus in Australia:

You confirm and warrant that you are either:

•

a “sophisticated investor” under section 708(8)(a) or (b) of the Corporations Act;

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•

a “sophisticated investor” under section 708(8)(c) or (d) of the Corporations Act and that you have provided an accountant’s certificate to the company which complies with the requirements of section 708(8)(c)(i) or (ii) of the Corporations Act and related regulations before the offer has been made; or

•

a “professional investor” within the meaning of section 708(11)(a) or (b) of the Corporations Act.

To the extent that you are unable to confirm or warrant that you are an exempt sophisticated investor or professional investor under the Corporations Act any offer made to you under this prospectus is void and incapable of acceptance.

You warrant and agree that you will not offer any of the shares issued to you pursuant to this prospectus for resale in Australia within 12 months of those securities being issued unless any such resale offer is exempt from the requirement to issue a disclosure document under section 708 of the Corporations Act.

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LEGAL MATTERS

The validity of the securities offered by us has been passed upon for us by Cooley LLP, Palo Alto, California, and for the underwriters by Duane Morris LLP, New York, New York.

EXPERTS

The consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2019 incorporated by reference in this prospectus, and the effectiveness of XOMA Corporation’s internal control over financial reporting have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports which are incorporated herein by reference. Such financial statements have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public at the SEC’s website at http://www.sec.gov.

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

This prospectus supplement and the accompanying prospectus is part of a registration statement on Form S-3. The SEC allows this filing to “incorporate by reference” information that we previously have filed with the SEC. This means we can disclose important information to you by referring you to other documents that we have filed with the SEC. The information that is incorporated by reference is considered part of this prospectus supplement and the accompanying prospectus, and information that we file later will automatically update and may supersede this information. For further information about our company and the securities being offered, you should refer to the registration statement and the following documents that are incorporated by reference:

•

our Annual Report on Form 10-K for the fiscal year ended December 31, 2019 filed with the SEC on March 10, 2020;

•

our Quarterly Reports on Form 10-Q for the fiscal quarters ended March 31, 2020, June 30, 2020 and September 30, 2020 filed with the SEC on May 5, 2020, August 6, 2020 and November 5, 2020, respectively;

•

our Current Reports on Form 8-K filed with the SEC on March 9, 2020, April 2, 2020, May 22, 2020, July 2, 2020, October 28, 2020 and November 16, 2020;

•

the portions of our Definitive Proxy Statement on Schedule 14A filed with the SEC on April 9, 2020 that are incorporated by reference into our Annual Report on Form 10-K for the fiscal year ended December 31, 2019; and

•

the description of our capital stock included under the caption “Description of Capital Stock” in the prospectus dated December 16, 2011, which was filed on December 19, 2011, and is part of our registration statement on Form S-4/A filed on December 13, 2011 (registration no. 333-177165), including any amendment or report for the purpose of updating such description.

In addition, all documents filed by us under Sections 13(a), 14 or 15(d) of the Exchange Act (excluding, unless otherwise provided in this prospectus supplement or in the applicable document, documents not deemed “filed” with the SEC and information furnished pursuant to Item 2.02 and Item 7.01 on any Current Report on Form 8-K or certain exhibits furnished pursuant to Item 9.01 of Form 8-K), after the date of this prospectus supplement but before the termination of the rights offering covered by this prospectus supplement, are hereby incorporated by reference herein. We have not authorized anyone to provide you with any different or additional information other than that contained in or incorporated by reference into this prospectus supplement and the accompanying prospectus. We take no responsibility for, and can provide no assurance as to the reliability of, any information that others may provide.

Any statement contained in a document incorporated or deemed to be incorporated by reference into this prospectus supplement or the accompanying prospectus will be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in this prospectus supplement or any other subsequently filed document that is deemed to be incorporated by reference into this prospectus supplement modifies or supersedes the statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement.

The documents incorporated by reference into this prospectus supplement and the accompanying prospectus are available from us upon request. We will provide a copy of any and all of the documents incorporated by reference (excluding exhibits, unless the exhibits are specifically incorporated), without charge, upon written or oral request. Requests for any of these documents should be directed to:

XOMA Corporation

2200 Powell Street, Suite 310

Emeryville, California 94608

(510) 204-7200

Attn: Chief Financial Officer

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PROSPECTUS

$300,000,000

LOGO

Common Stock

Preferred Stock

Debt Securities

Warrants

We may, from time to time, offer and sell up to $300,000,000 of any combination of our common stock, preferred stock, debt securities or warrants described in this prospectus, either individually or in combination with other securities, at prices and on terms described in one or more supplements to this prospectus. We may also offer common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings.

This prospectus describes some of the general terms that may apply to an offering of our securities. The specific terms and any other information relating to a specific offering will be set forth in supplement to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. You should read this prospectus, the information incorporated by reference in this prospectus and any applicable prospectus supplement or free writing prospectus carefully before you invest.

Securities may be sold by us to or through underwriters or dealers, directly to purchasers or through agents designated from time to time. For additional information on the methods of sale, you should refer to the section under the heading “Plan of Distribution” in this prospectus and under a similar heading in the applicable prospectus supplement. If any underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such underwriters and any applicable discounts or commissions and over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

Our common stock is listed on the Nasdaq Global Market under the symbol “XOMA” On March 6, 2018, the last reported sale price of our common stock on the Nasdaq Global Market was $26.49 per share.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and in any free writing prospectuses we have authorized for use in connection with a specific offering, and under similar headings in the documents that are incorporated by reference into this prospectus.

This prospectus may not be used to offer or sell any securities unless accompanied by a prospectus supplement.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is April 5, 2018

TABLE OF CONTENTS


	Page
About this Prospectus		i
Prospectus Summary		1
Risk Factors		5
Forward-Looking Statements		5
Financial Ratios		6
Use of Proceeds		6
Description of Capital Stock		7
Description of Debt Securities		13
Description of Warrants		20
Legal Ownership of Securities		22
Plan of Distribution		26
Legal Matters		28
Experts		28
Where You Can Find More Information		28
Incorporation of Certain Information by Reference		29

You should rely only on the information contained in or incorporated by reference into this prospectus or any applicable prospectus supplement or free writing prospectus. We have not authorized anyone to provide you with different information. We are not making an offer to sell or seeking an offer to buy securities under this prospectus or any applicable prospectus supplement or free writing prospectus in any jurisdiction where the offer or sale is not permitted. The information contained in this prospectus, any applicable prospectus supplement or free writing prospectus and the documents incorporated by reference herein and therein are accurate only as of their respective dates, regardless of the time of delivery of this prospectus or any sale of a security.

About this Prospectus

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, using a “shelf” registration process. Under this shelf registration statement, we may sell from time to time in one or more offerings up to a total dollar amount of $300,000,000 of common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in combination with other securities as described in this prospectus. Each time we sell any type or series of securities under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. We may also add, update or change in a prospectus supplement or free writing prospectus any of the information contained in this prospectus or in documents we have incorporated by reference into this prospectus. This prospectus, together with any applicable prospectus supplement or free writing prospectus and the documents incorporated by reference into this prospectus, include all material information relating to this offering. You should carefully read both this prospectus and any applicable prospectus supplement and any related free writing prospectus together with the additional information described under “Where You Can Find More Information” before buying securities in this offering.

You should rely only on the information contained in, or incorporated by reference into, this prospectus and the applicable prospectus supplement, along with the information contained in any free writing prospectuses we have authorized for use in connection with a specific offering. We have not authorized anyone to provide you

with different or additional information. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so.

The information appearing in this prospectus, any applicable prospectus supplement and any related free writing prospectus is accurate only as of the date on the front of the document and any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus, the applicable prospectus supplement or any related free writing prospectus, or any sale of a security. Our business, financial condition, results of operations and prospects may have changed since those dates.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the section entitled “Where You Can Find More Information.”

Unless otherwise specified or required by context, references in this prospectus to “XOMA,” “the Company,” “we,” “us” and “our” refer to XOMA Corporation, a Delaware corporation and its consolidated subsidiaries, if any, unless otherwise specified.

Prospectus Summary

This summary highlights selected information contained elsewhere in this prospectus or incorporated by reference herein and does not contain all the information that may be important to purchasers of our securities. Prospective purchasers of our securities should carefully read the entire prospectus, the applicable prospectus supplement and any related free writing prospectus, including the risks of investing in our securities discussed under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. Prospective purchasers of our securities should also carefully read the information incorporated by reference into this prospectus, including our financial statements, and the exhibits to the registration statement of which this prospectus is a part.

This prospectus and the information incorporated herein by reference include trademarks, service marks and trade names owned by us or other companies. All trademarks, service marks and trade names included or incorporated by reference into this prospectus or any related free writing prospectus are the property of their respective owners.

XOMA CORPORATION

Overview

We are a Delaware corporation with a long history of discovering and developing innovative therapeutics derived from our unique platform of antibody technologies. Over our 37-year history, we built an extensive portfolio of fully-funded programs by advancing product candidates into the earlier stages of development and then licensing them to licensees who assumed the responsibilities of later stage development, approval and commercialization. Fully-funded programs are those for which our partners pay all of the development and commercialization costs. As licensees advance these programs, we are eligible for potential milestone and royalty payments.

In March 2017, we transformed our business model to become a royalty aggregator where we focus on expanding our portfolio of fully-funded programs by out-licensing our internally developed product candidates and acquiring potential milestone and royalty revenue streams on additional product candidates. We combined our royalty-aggregator model with a significantly reduced corporate cost structure to further build value for our stockholders. We expect that a significant portion of our future revenue will be based on payments we may receive for milestones and royalties related to these programs.

We have designed our business model to create value for stockholders by assembling a diversified portfolio of biotech and pharmaceutical revenue streams and operating that business with an efficient and low corporate cost structure. Our goal is to become a sustainably profitable company that offers investors an opportunity to participate in the promise of the biotech industry in a diversified, lower-risk business investment than a typical biotech model.

Risks Associated with our Business

Our business is subject to numerous risks, as described under the heading “Risk Factors” contained in the applicable prospectus supplement and in any free writing prospectuses we have authorized for use in connection with a specific offering, and under similar headings in the documents that are incorporated by reference into this prospectus.

Company Information

We were incorporated in Delaware in 1981 and became a Bermuda exempted company in December 1998. Effective December 31, 2011, we changed our jurisdiction of incorporation from Bermuda to Delaware and changed our name from XOMA Ltd. to XOMA Corporation.

Our principal executive offices are located at 2200 Powell Street, Suite 310, Emeryville, California 94608, and we maintain a registered office located at Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware 19801. Our telephone number at our principal executive offices is (510) 204-7200. Our website address is www.xoma.com. Information found on, or accessible through, our website is not a part of, and is not incorporated into, this prospectus, and you should not consider it part of this prospectus or part of any prospectus supplement. Our website address is included in this document as an inactive textual reference only.

Nasdaq Global Market Listing

Our common stock is listed on The Nasdaq Global Market under the symbol “XOMA.”

The Securities We May Offer

We may offer shares of our common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in combination with other securities, with a total value of up to $300,000,000 from time to time under this prospectus, together with the applicable prospectus supplement and any related free writing prospectus, at prices and on terms to be determined at the time of any offering. We may also offer common stock, preferred stock and/or debt securities upon the exercise of warrants. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

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designation or classification;

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aggregate principal amount or aggregate offering price;

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maturity date, if applicable;

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original issue discount, if any;

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rates and times of payment of interest or dividends, if any;

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redemption, conversion, exercise, exchange or sinking fund terms, if any;

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ranking;

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restrictive covenants, if any;

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voting or other rights, if any;

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conversion or exchange prices or rates, if any, and, if applicable, any provisions for changes to or adjustments in the conversion or exchange prices or rates and in the securities or other property receivable upon conversion or exchange; and

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a discussion of material United States federal income tax considerations, if any.

The applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

This prospectus may not be used to consummate the sale of securities unless it is accompanied by a prospectus supplement.

We may sell the securities directly to investors or to or through agents, underwriters or dealers. We, and our agents, underwriters or dealers reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities to or through agents, underwriters or dealers, we will include in the applicable prospectus supplement:

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the names of those agents, underwriters or dealers;

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applicable fees, discounts and commissions to be paid to them;

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details regarding over-allotment options, if any; and

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the net proceeds to us.

Common Stock. We may issue shares of our common stock from time to time. Common stockholders are entitled to one vote per share for the election of directors and on all other matters that require common stockholder approval. Holders of our common stock are entitled to share in an equal amount per share in any dividends declared by our board of directors on the common stock and paid out of legally available assets. Subject to any preferential rights of any outstanding preferred stock, in the event of our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in the assets remaining after payment of liabilities and the liquidation preferences of any outstanding preferred stock. Our common stock does not carry any preemptive rights enabling a holder to subscribe for, or receive shares of, any class of our common stock or any other securities convertible into shares of any class of our common stock, or any redemption rights. There are no redemption or sinking fund provisions applicable to our common stock. In this prospectus, we have summarized certain general features of the common stock under “Description of Capital Stock – Common Stock.” We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to any common stock being offered.

Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. Under our certificate of incorporation, our board of directors has the authority to designate up to 1,000,000 shares of preferred stock in one or more series and to fix the privileges, preferences and rights of each series of preferred stock, any or all of which may be greater than the rights of the common stock. Currently, of 1,000,000 shares of preferred stock, 5,003 shares are designated as Series X Preferred Stock. If we sell any new series of preferred stock under this prospectus and any applicable prospectus supplement, our board of directors will determine the designations, voting powers, preferences and rights of the preferred stock, as well as the qualifications, limitations or restrictions thereof, including dividend rights, conversion rights, preemptive rights, terms of redemption or repurchase, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of any series. Convertible preferred stock will be convertible into our common stock or exchangeable for other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates.

If we sell any series of preferred stock under this prospectus, we will fix the designations, voting powers, preferences and rights of such series of preferred stock, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that contains the terms of the series of preferred stock that we are offering before the issuance of the related series of preferred stock. In this prospectus, we have summarized certain general features of the preferred stock under “Description of Capital Stock – Preferred Stock.” We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Debt Securities. We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into or exchangeable for our common stock or other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates.

Any debt securities issued under this prospectus will be issued under one or more documents called indentures, which are contracts between us and a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities under “Description of Debt Securities.” We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. We have filed the form of indenture as an exhibit to the registration statement of which this prospectus is a part, and we will file supplemental indentures and forms of debt securities containing the terms of the debt securities being offered as exhibits to the registration statement of which this prospectus is a part or we will incorporate them by reference from reports that we file with the SEC.

Warrants. We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and/or debt securities. In this prospectus, we have summarized certain general features of the warrants under “Description of Warrants.” We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to the series of warrants being offered, as well as any warrant agreements and warrant certificates that contain the terms of the warrants. We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that may be offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants.

Any warrants issued under this prospectus may be evidenced by warrant certificates. Warrants also may be issued under an applicable warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.

Use of Proceeds

Except as described in any applicable prospectus supplement or in any free writing prospectuses we have authorized for use in connection with a specific offering, we currently intend to use the net proceeds from the sale of the securities offered by us hereunder, if any, for working capital and general corporate purposes, including capital expenditures.

Risk Factors

Investing in our securities involves a high degree of risk. Before deciding whether to invest in our securities, you should consider carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and discussed under the section entitled “Risk Factors” contained in our most recent Annual Report on Form 10-K and in our most recent Quarterly Report on Form 10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC, which are incorporated by reference into this prospectus in their entirety, together with other information in this prospectus, the documents incorporated by reference and any free writing prospectus that we may authorize for use in connection with this offering. The risks described in these documents are not the only ones we face, but those that we consider to be material. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects on our future results. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment. Please also read carefully the section below entitled “Forward-Looking Statements.”

Forward-Looking Statements

This prospectus, including the documents that we incorporate by reference herein, contains, and any applicable prospectus supplement or free writing prospectus may contain, forward-looking statements that relate to future periods, which are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the Private Securities Litigation Reform Act of 1995, which are subject to the “safe harbor” created by those sections. The words “believe,” “may,” “estimate,” “continue,” “anticipate,” “intend,” “expect,” “predict,” “project,” “potential,” “believe,” “should,” “could” and similar expressions are intended to identify forward-looking statements. Examples of these statements include, but are not limited to, statements regarding: the sufficiency of our cash resources, our future operating expenses, our future losses, the extent to which our issued and pending patents may protect our products and technology, the potential of our existing product candidates to lead to the development of commercial products, our ability to receive potential milestone or royalty payments under license and collaboration agreements and the timing of receipt of those payments, the timing and adequacy of cost-cutting measures, and our ability to defend against claims that have been made in litigation. These statements are based on assumptions that may not prove accurate. Actual results could differ materially from those anticipated due to certain risks inherent in the biotechnology industry and for our licensees engaged in the development of new products in a regulated market. Among other things, these risks include: our product candidates subject to out-license agreements are still being developed, and our licensees may require substantial funds to continue development which may not be available; we may not realize the expected benefits of our cost-saving initiatives; we may not be successful in entering into out-license agreements for our product candidates; if our therapeutic product candidates do not receive regulatory approval, our third-party licensees will not be able to manufacture and market them; products or technologies of other companies may render some or all of our product candidates noncompetitive or obsolete; we do not know whether there will be, or will continue to be, a viable market for the products in which we have an ownership or royalty interest; even once approved, a product may be subject to additional testing or significant marketing restrictions, its approval may be withdrawn or it may be voluntarily taken off the market; we and our licensees are subject to various state and federal healthcare related laws and regulations that may impact the commercialization of our product candidates and could subject us to significant fines and penalties; and certain of our technologies are in-licensed from third parties, so our capabilities using them are restricted and subject to additional risks. These and other risks, including those related to current economic and financial market conditions, are described in more detail in “Risk Factors” above and the additional risk factors contained in our most recent Annual Report on Form 10-K and Quarter Reports on Form 10-Q. We undertake no obligation to publicly update any forward-looking statements, regardless of any new information, future events or other occurrences. We advise you, however, to consult any additional disclosures we make in our reports to the SEC on Forms 10-K, 10-Q and 8-K.

Financial Ratios

The following table sets forth our ratio of earnings to fixed charges and preferred stock dividends and the amount of deficiency for periods in which the ratio indicates less than one-to-one coverage.


	Year Ended December 31,
	2017			2016			2015			2014			2013
	(in thousands)
Ratio of Earnings to Fixed Charges and Preferred Stock Dividends (1)		9.58 (2	)		N/A			N/A			N/A			N/A
Deficiency of Earnings Available to Cover Fixed Charges		N/A			(53,530	)		(20,606	)		(38,301	)		(124,072	)

(1)

We have not had any preferred stock subject to dividends outstanding during the periods presented (other than the non-cash deemed dividend described in footnote (2) below, which is excluded for purposes of this calculation); therefore, the ratio of earnings to (and the deficiency of earnings available to cover) combined fixed charges and preferred stock dividends is the same as our ratio of earnings to (and the deficiency of earnings available to cover) fixed charges alone.

(2)

The ratio of earnings available to cover combined fixed charges and preference dividends for the year ended December 31, 2017 excludes non-cash deemed dividends to preferred stockholders of $5.6 million related to the issuance of our convertible preferred stock in connection with a private placement.

For these purposes, earnings are defined as income before income taxes and fixed charges, and fixed charges include interest expense on indebtedness, and the portion of operating lease rental expense, which is deemed to represent interest. The deficiency is disclosed for periods in which net losses were insufficient to cover fixed charges.

Use of Proceeds

The amounts and timing of our use of the net proceeds from this offering will depend on a number of factors, such as the timing and progress of any partnering and commercialization efforts, technological advances and the competitive environment for our products. As of the date of this prospectus, we cannot specify with certainty all of the particular uses for the net proceeds to us from the sale of the securities offered by us hereunder. Accordingly, our management will have broad discretion in the timing and application of these proceeds. Pending application of the net proceeds as described above, we intend to temporarily invest the proceeds in short-term, interest-bearing instruments.

Description of Capital Stock

As of the date of this prospectus, our certificate of incorporation, as amended, authorizes us to issue 277,333,332 shares of common stock, par value $0.0075 per share, and 1,000,000 shares of preferred stock, par value $0.05 per share.

The following summary describes the material terms of our capital stock. The description of capital stock is qualified by reference to our certificate of incorporation and our bylaws.

Common Stock

Dividends and distributions. 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. We have not paid cash dividends on the common stock. We currently do not intend to pay dividends and intend to retain any of our earnings for use in our business and the financing of our capital requirements for the foreseeable future. The payment of any future cash dividends on the common stock is necessarily dependent upon our earnings and financial needs, along with applicable legal and contractual restrictions.

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 Delaware General Corporation Law, or the DGCL, the certificate of incorporation, the bylaws, 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).

Restrictions on transfer. Neither our certificate of incorporation nor our bylaws contain any restrictions on the transfer of our common stock. However, in the case of any transfer of shares, there may be restrictions imposed by applicable securities laws or by the terms of restricted share award grants.

Other Provisions. There are no redemption provisions or sinking fund provisions applicable to our common stock.

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

General. Under our certificate of incorporation, our board of directors is authorized 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 of terms of our preferred stock is not complete. You should refer to the provisions of our certificate of incorporation and bylaws and the resolutions containing the terms of each class or series of the preferred stock which have been or will be filed with the SEC at or prior to the time of issuance of such class or series of preferred stock and described in the applicable prospectus supplement. The applicable prospectus supplement may also state that any of the terms set forth herein are inapplicable to such series of preferred stock, provided that the information set forth in such prospectus supplement does not constitute material changes to the information herein such that it alters the nature of the offering or the securities offered.

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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senior to any class or series of our capital stock created specifically ranking by its terms junior to the Series X Preferred Stock;

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on parity to our common stock;

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on parity to any class or series of our capital stock created specifically ranking by its terms on parity with the Series X Preferred Stock; and

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junior to any class or series of our capital stock created specifically ranking by its terms senior to the Series X Preferred Stock;

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 if converted to common stock 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.

Exchange Listing. We have not made and do not plan on making an application to list the Series X Preferred Stock on the Nasdaq Global Market, any national securities exchange or other nationally recognized trading system. We expect the common stock issuable upon conversion of the Series X Preferred Stock to be listed on the Nasdaq Global Market.

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 Exchange Act 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 common share 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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a merger or consolidation of the Company with or into another entity or any stock sale to, or other business combination in which the Company is not the surviving entity;

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the sale of all or substantially all of our assets in one transaction or a series of related transactions;

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any completed tender offer or exchange offer involving holders of common stock in which more than 50% of the common stock is converted or exchanged into other securities, cash or property, regardless of who makes such offer; or

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any reclassification of common stock or any compulsory share exchange by which our common stock is effectively converted into or exchanged for other securities, cash or property (but not a reverse stock split).

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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amend our articles of incorporation, bylaws or other charter documents so as to materially, specifically and adversely affect the preferences, rights, privileges of the Series X Preferred Stock;

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issue additional shares of Series X Preferred Stock or increase or decrease the number of authorized shares of Series X Preferred Stock;

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sell, assign, monetize, pledge or otherwise divest or encumber our rights under any material license agreement, joint venture or other partnership agreement to which we are a party as of the date of this offering and involving any drug or drug candidate;

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issue or commit to issue any other equity securities, with certain exceptions;

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issue any equity-based award or compensation to certain of our officers, unless the award has been unanimously approved by our compensation committee at a time when a designee appointed by the Series X Preferred holders is then serving on that committee; or

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enter into any agreement or understanding to take any of the actions listed above.

Preferred Stock. We will fix the designations, voting powers, preferences and rights of the preferred stock of each series we issue under this prospectus, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering. We will describe in the applicable prospectus supplement the terms of the series of preferred stock being offered, including, to the extent applicable:

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the title and stated value;

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the number of shares we are offering;

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the liquidation preference per share;

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the purchase price;

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the dividend rate, period and payment date and method of calculation for dividends;

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whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

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the procedures for any auction and remarketing, if applicable;

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the provisions for a sinking fund, if applicable;

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the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;

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any listing of the preferred stock on any securities exchange or market;

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whether the preferred stock will be convertible into our common stock, and, if applicable, the conversion price, or how it will be calculated, and the conversion period;

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whether the preferred stock will be exchangeable into debt securities, and, if applicable, the exchange price, or how it will be calculated, and the exchange period;

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voting rights of the preferred stock;

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preemptive rights, if any;

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restrictions on transfer, sale or other assignment;

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whether interests in the preferred stock will be represented by depositary shares;

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a discussion of material United States federal income tax considerations applicable to the preferred stock;

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the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;

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any limitations on the issuance of any class or series of preferred stock ranking senior to or on a parity with the series of preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and

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any other specific terms, preferences, rights or limitations of, or restrictions on, the preferred stock.

If we issue shares of preferred stock under this prospectus, the shares will be fully paid and non-assessable.

The issuance of preferred stock could adversely affect the voting power of holders of common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation. The issuance could have the effect of decreasing the market price of the common stock. The issuance of preferred stock also could have the effect of delaying, deterring or preventing a change in control of us.

Outstanding Warrants

In February 2016, in conjunction with services provided by a third-party consultant, we issued a warrant to purchase up to an aggregate of 8,249 unregistered shares of our common stock at an exercise price equal to $15.40 per share. This warrant was exercisable immediately and has a five-year term expiring in February 2021.

In February 2015, we issued a warrant in connection with a debt financing, which entitles the holder to purchase up to an aggregate of 9,063 unregistered shares of our common stock at an exercise price equal to $66.20 per share. The warrant was exercisable immediately and has a 5-year term expiring in 2020.

Anti-Takeover Effects of Our Charter Documents and Some Provisions of Delaware Law

Certificate of incorporation and bylaws. 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 bylaws 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 bylaws 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 bylaws 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.

Section 203 of the Delaware General Corporation 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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prior to the date of the transaction, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;

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upon completion 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 (a) shares owned by persons who are directors and also officers, and (b) shares owned 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

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on or subsequent to the date of the transaction, the business combination is approved by the board and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66% of the outstanding voting stock which is not owned by the interested stockholder.

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.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Wells Fargo Shareowner Services.

Listing on the Nasdaq Global Market

Our common stock is listed on the Nasdaq Global Market under the symbol “XOMA.”

DESCRIPTION OF DEBT SECURITIES

We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue the debt securities under the indenture that we will enter into with the trustee named in the indenture. The indenture will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We have filed the form of indenture as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

The following summary of material provisions of the debt securities and the indenture is subject to, and qualified in its entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indenture that contains the terms of the debt securities.

General

The indenture does not limit the amount of debt securities that we may issue. It provides that we may issue debt securities up to the principal amount that we may authorize and may be in any currency or currency unit that we may designate. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us.

We may issue the debt securities issued under the indenture as “discount securities,” which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may be issued with “original issue discount,” or OID, for U.S. federal income tax purposes because of interest payment and other characteristics or terms of the debt securities. Material U.S. federal income tax considerations applicable to debt securities issued with OID will be described in more detail in any applicable prospectus supplement.

We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:

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the title of the series of debt securities;

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any limit upon the aggregate principal amount that may be issued;

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the maturity date or dates;

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the form of the debt securities of the series;

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the applicability of any guarantees;

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whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

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whether the debt securities rank as senior debt, senior subordinated debt, subordinated debt or any combination thereof, and the terms of any subordination;

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if the price (expressed as a percentage of the aggregate principal amount thereof) at which such debt securities will be issued is a price other than the principal amount thereof, the portion of the principal amount thereof payable upon declaration of acceleration of the maturity thereof, or if applicable, the portion of the principal amount of such debt securities that is convertible into another security or the method by which any such portion shall be determined;

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the interest rate or rates, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

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our right, if any, to defer payment of interest and the maximum length of any such deferral period;

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if applicable, the date or dates after which, or the period or periods during which, and the price or prices at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

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the date or dates, if any, on which, and the price or prices at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

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the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

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any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;

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whether the debt securities of the series shall be issued in whole or in part in the form of a global security or securities; the terms and conditions, if any, upon which such global security or securities may be exchanged in whole or in part for other individual securities; and the depositary for such global security or securities;

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if applicable, the provisions relating to conversion or exchange of any debt securities of the series and the terms and conditions upon which such debt securities will be so convertible or exchangeable, including the conversion or exchange price, as applicable, or how it will be calculated and may be adjusted, any mandatory or optional (at our option or the holders’ option) conversion or exchange features, the applicable conversion or exchange period and the manner of settlement for any conversion or exchange;

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if other than the full principal amount thereof, the portion of the principal amount of debt securities of the series which shall be payable upon declaration of acceleration of the maturity thereof;

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additions to or changes in the covenants applicable to the particular debt securities being issued, including, among others, the consolidation, merger or sale covenant;

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additions to or changes in the events of default with respect to the securities and any change in the right of the trustee or the holders to declare the principal, premium, if any, and interest, if any, with respect to such securities to be due and payable;

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additions to or changes in or deletions of the provisions relating to covenant defeasance and legal defeasance;

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additions to or changes in the provisions relating to satisfaction and discharge of the indenture;

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additions to or changes in the provisions relating to the modification of the indenture both with and without the consent of holders of debt securities issued under the indenture;

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the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars;

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whether interest will be payable in cash or additional debt securities at our or the holders’ option and the terms and conditions upon which the election may be made;

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the terms and conditions, if any, upon which we will pay amounts in addition to the stated interest, premium, if any and principal amounts of the debt securities of the series to any holder that is not a “United States person” for federal tax purposes;

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any restrictions on transfer, sale or assignment of the debt securities of the series; and

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any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, any other additions or changes in the provisions of the indenture, and any terms that may be required by us or advisable under applicable laws or regulations.

Conversion or Exchange Rights

We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to settlement upon conversion or exchange and whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of our assets as an entirety or substantially as an entirety. However, any successor to or acquirer of such assets (other than a subsidiary of ours) must assume all of our obligations under the indenture or the debt securities, as appropriate.

Events of Default under the Indenture

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:

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if we fail to pay any installment of interest on any series of debt securities, as and when the same shall become due and payable, and such default continues for a period of 90 days; provided, however, that a valid extension of an interest payment period by us in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of interest for this purpose;

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if we fail to pay the principal of, or premium, if any, on any series of debt securities as and when the same shall become due and payable whether at maturity, upon redemption, by declaration or otherwise, or in any payment required by any sinking or analogous fund established with respect to such series; provided, however, that a valid extension of the maturity of such debt securities in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of principal or premium, if any;

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if we fail to observe or perform any other covenant or agreement contained in the debt securities or the indenture, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive written notice of such failure, requiring the same

to be remedied and stating that such is a notice of default thereunder, from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and

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if specified events of bankruptcy, insolvency or reorganization occur.

If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:

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the direction so given by the holder is not in conflict with any law or the applicable indenture; and

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subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

A holder of the debt securities of any series will have the right to institute a proceeding under the indenture or to appoint a receiver or trustee, or to seek other remedies only if:

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the holder has given written notice to the trustee of a continuing event of default with respect to that series;

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the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request,

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such holders have offered to the trustee indemnity satisfactory to it against the costs, expenses and liabilities to be incurred by the trustee in compliance with the request; and

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the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the indenture.

Modification of Indenture; Waiver

We and the trustee may change an indenture without the consent of any holders with respect to specific matters:

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to cure any ambiguity, defect or inconsistency in the indenture or in the debt securities of any series;

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to comply with the provisions described above under “Description of Debt Securities—Consolidation, Merger or Sale;”

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to provide for uncertificated debt securities in addition to or in place of certificated debt securities;

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to add to our covenants, restrictions, conditions or provisions such new covenants, restrictions, conditions or provisions for the benefit of the holders of all or any series of debt securities, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default or to surrender any right or power conferred upon us in the indenture;

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to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;

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to make any change that does not adversely affect the interests of any holder of debt securities of any series in any material respect;

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to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided above under “Description of Debt Securities—General” to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;

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to evidence and provide for the acceptance of appointment under any indenture by a successor trustee; or

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to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act.

In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:

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extending the fixed maturity of any debt securities of any series;

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reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption of any series of any debt securities; or

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reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.

Discharge

Each indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

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provide for payment;

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replace stolen, lost or mutilated debt securities of the series;

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pay principal of and premium and interest on any debt securities of the series;

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maintain paying agencies;

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hold monies for payment in trust;

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recover excess money held by the trustee;

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compensate and indemnify the trustee; and

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appoint any successor trustee.

In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium, if any, and interest on, the debt securities of the series on the dates payments are due.

Form, Exchange and Transfer

We will issue the debt securities of each series only in fully registered form without coupons and, unless we provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indenture provides that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company, or DTC, or another depositary named by us and identified in the applicable prospectus supplement with respect to that series. To the extent the debt securities of a series are issued in global form and as book-entry, a description of terms relating to any book-entry securities will be set forth in the applicable prospectus supplement.

At the option of the holder, subject to the terms of the indenture and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem the debt securities of any series, we will not be required to:

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issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or

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register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.

Information Concerning the Trustee

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the trustee is under no obligation to exercise any of the powers given it by the indenture at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

Governing Law

The indenture and the debt securities will be governed by and construed in accordance with the internal laws of the State of New York, except to the extent that the Trust Indenture Act of 1939 is applicable.

DESCRIPTION OF WARRANTS

The following description, together with the additional information we may include in any applicable prospectus supplements and in any related free writing prospectuses that we may authorize to be distributed to you, summarizes the material terms and provisions of the warrants that we may offer under this prospectus, which may consist of warrants to purchase common stock, preferred stock and/or debt securities and may be issued in one or more series. Warrants may be offered independently or in combination with common stock, preferred stock or debt securities offered by any prospectus supplement. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The following description of warrants will apply to the warrants offered by this prospectus unless we provide otherwise in the applicable prospectus supplement. The applicable prospectus supplement for a particular series of warrants may specify different or additional terms.

We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that may be offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants. The following summaries of material terms and provisions of the warrants are subject to, and qualified in their entirety by reference to, all the provisions of the form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements applicable to a particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplement related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectus, and the complete form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements, that contain the terms of the warrants.

General

We will describe in the applicable prospectus supplement the terms of the series of warrants being offered, including, to the extent applicable:

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the offering price and aggregate number of warrants offered;

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the currency for which the warrants may be purchased;

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the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

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in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

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in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which these shares may be purchased upon such exercise;

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the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;

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the terms of any rights to redeem or call the warrants;

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any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;

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the dates on which the right to exercise the warrants will commence and expire;

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the manner in which the warrant agreements and warrants may be modified;

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a discussion of material or special U.S. federal income tax consequences of holding or exercising the warrants;

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the terms of the securities issuable upon exercise of the warrants; and

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any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

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in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or, payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any; or

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in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture.

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. The warrants may be exercised as set forth in the prospectus supplement relating to the warrants offered. Unless we otherwise specify in the applicable prospectus supplement, warrants may be exercised at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Upon receipt of payment and the warrant or warrant certificate, as applicable, properly completed and duly executed at the corporate trust office of the warrant agent, if any, or any other office, including ours, indicated in the prospectus supplement, we will, as soon as practicable, issue and deliver the securities purchasable upon such exercise. If less than all of the warrants (or the warrants represented by such warrant certificate) are exercised, a new warrant or a new warrant certificate, as applicable, will be issued for the remaining warrants.

Governing Law

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements, and any claim, controversy or dispute arising under or related to the warrants or warrant agreements, will be governed by and construed in accordance with the laws of the State of New York.

Enforceability of Rights by Holders of Warrants

Each warrant agent, if any, will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

LEGAL OWNERSHIP OF SECURITIES

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants. Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a book-entry security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not legal holders, of the securities.

Street Name Holders

We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we or any applicable trustee or depositary will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we or any applicable trustee or depositary will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee and of any third parties employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the legal holder, we have no further responsibility for the payment or notice even if that legal holder is required, under agreements with its participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the legal holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of the indenture or for other purposes. In such an event, we would seek approval only from the holders, and not the indirect holders, of the securities. Whether and how the legal holders contact the indirect holders is up to the legal holders.

Special Considerations for Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form because the securities are represented by one or more global securities or in street name, you should check with your own institution to find out:

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how it handles securities payments and notices;

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whether it imposes fees or charges;

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how it would handle a request for the holders’ consent, if ever required;

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whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;

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how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and

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if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.

Global Securities

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we issue to, deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, DTC will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under “Special Situations When a Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and legal holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a legal holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations for Global Securities

The rights of an indirect holder relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only in the form of a global security, an investor should be aware of the following:

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an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

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an investor will be an indirect holder and must look to his or her own bank, broker or other financial institution for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;

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an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

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an investor may not be able to pledge his or her interest in a global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

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the depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in a global security;

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we and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in a global security, nor do we or any applicable trustee supervise the depositary in any way;

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the depositary may, and we understand that DTC will, require that those who purchase and sell interests in a global security within its book-entry system use immediately available funds, and your bank, broker or other financial institution may require you to do so as well; and

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financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in a global security, may also have their own policies affecting payments, notices and other matters relating to the securities.

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When a Global Security Will Be Terminated

In a few special situations described below, the global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks, brokers or other financial institutions to find out how to have their interests in securities transferred to their own name, so that they will be direct holders. We have described the rights of holders and street name investors above.

Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:

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if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;

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if we notify any applicable trustee that we wish to terminate that global security; or

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if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.

The applicable prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

PLAN OF DISTRIBUTION

We may sell the securities from time to time pursuant to underwritten public offerings, direct sales to the public, “at the market” offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:

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at a fixed price or prices, which may be changed;

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at market prices prevailing at the time of sale;

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at prices related to such prevailing market prices; or

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at negotiated prices.

A prospectus supplement or supplements (and any related free writing prospectus that we may authorize to be provided to you) will describe the terms of the offering of the securities, including, to the extent applicable:

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the name or names of the underwriters, if any;

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the purchase price of the securities or other consideration therefor, and the proceeds, if any, we will receive from the sale;

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any over-allotment or other options under which underwriters may purchase additional securities from us;

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any agency fees or underwriting discounts and other items constituting agents’ or underwriters’ compensation;

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any public offering price;

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any discounts or concessions allowed or reallowed or paid to dealers; and

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any securities exchange or market on which the securities may be listed.

Only underwriters named in the prospectus supplement will be underwriters of the securities offered by the prospectus supplement.

If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement, other than securities covered by any over-allotment or other option. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.

We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in an applicable prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in an applicable prospectus supplement pursuant

to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

We may provide agents and underwriters with indemnification against civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

All securities we may offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in over-allotment, stabilizing transactions, short-covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Over-allotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum price. Syndicate-covering or other short-covering transactions involve purchases of the securities, either through exercise of the over-allotment option or in the open market after the distribution is completed, to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time.

Any underwriters or agents that are qualified market makers on the Nasdaq Global Market may engage in passive market making transactions in the common stock on the Nasdaq Global Market in accordance with Regulation M under the Exchange Act, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the common stock. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

In compliance with guidelines of the Financial Industry Regulatory Authority, or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and any applicable prospectus supplement.

LEGAL MATTERS

The validity of the securities being offered hereby will be passed upon for us by Cooley LLP, Palo Alto, California.

EXPERTS

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2017, which are incorporated by reference in this prospectus and elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on Ernst & Young LLP’s reports, given on their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any document we file with the SEC at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C., 20549. Please call the SEC at 1.800.SEC.0330 for further information on the operation of the public reference room. Our SEC filings are also available to the public at the SEC’s website at http://www.sec.gov.

Incorporation of Certain Information by Reference

The SEC allows us to “incorporate by reference” the information we file with it, which means that we can disclose important information to you by referring you to those documents instead of having to repeat the information in this prospectus. The information incorporated by reference is considered to be part of this prospectus, and later information that we file with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below and any future filings (including those made after the date of the initial filing of the registration statement of which this prospectus is a part and prior to the effectiveness of such registration statement) we will make with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act until the termination of the offering of the shares covered by this prospectus (other than information furnished under Item 2.02 or Item 7.01 of Form 8-K):

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our annual report on Form 10-K for the year ended December 31, 2017, filed with the SEC on March 7, 2018, including the information specifically incorporated by reference therein from our definitive proxy statement to be filed with the SEC;

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Any statements we may in any future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later-filed document modify or replace such earlier statements. We will furnish without charge to each person, including any beneficial owner, to whom a prospectus is delivered, upon written or oral request, a copy of any or all of the documents incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits that are specifically incorporated by reference into such documents.

You can request a copy of these filings, at no cost, by writing or telephoning us at the following address or telephone number:

XOMA Corporation

2200 Powell Street, Suite 310

Emeryville, California 94608

(510) 204-7200

Attn: Chief Financial Officer

This prospectus is part of a registration statement we filed with the SEC. That registration statement and the exhibits filed along with the registration statement contain more information about us and the shares in this offering. Because information about documents referred to in this prospectus is not always complete, you should read the full documents which are filed as exhibits to the registration statement. You may read and copy the full registration statement and its exhibits at the SEC’s public reference rooms or its website.

LOGO

XOMA CORPORATION

Shares of % Series A Cumulative Perpetual Preferred Stock

(Liquidation Preference of $25.00 Per Share)

PROSPECTUS SUPPLEMENT

Joint Book-Runners


B. Riley Securities		Ladenburg Thalmann		National Securities Corporation		William Blair & Company

Co-Managers


Aegis Capital Corp.		Boenning & Scattergood		Northland Capital Markets

December , 2020

XOMA (XOMA) 424B5Prospectus supplement for primary offering