FORM OF PREFERRED STOCK SUBSCRIPTION AGREEMENT THIS PREFERRED STOCK SUBSCRIPTION AGREEMENT, dated as of the date of acceptance set forth below, by and between XOMA CORPORATION, a Delaware corporation, with headquarters located at 2910 Seventh Street, Berkeley, California 94710 (the "Company"), and the undersigned (the "Buyer"). W I T N E S S E T H : WHEREAS, the Company and the Buyer are executing and delivering this Agreement in reliance upon the exemption from securities registration afforded by Rule 506 under Regulation D ("Regulation D") as promulgated by the United States Securities and Exchange Commission (the "SEC") under the Securities Act of 1933, as amended (the "1933 Act"); and WHEREAS, the Buyer wishes to subscribe for and purchase shares of non-voting convertible preferred stock of the Company, which will be convertible into shares of Common Stock, $.0005 par value, and the related Preferred Stock Purchase Rights (the "Common Stock") of the Company, upon the terms and subject to the conditions of this Agreement, subject to acceptance of this Agreement by the Company; NOW THEREFORE, in consideration of the premises and the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties agree as follows: 1. AGREEMENT TO SUBSCRIBE; PURCHASE PRICE. (a) Subscription. The undersigned hereby subscribes for and agrees to purchase from the Company shares (the "Preferred Shares") of Non-Voting Cumulative Convertible Preferred Stock, Series F, $.05 par value (the "Series F Preferred Stock"), of the Company in such number as is set forth on the signature page of this Agreement (subject to reduction as provided in Section 7(b)) at the price per Share and for the aggregate subscription price set forth on the signature page of this Agreement. The Preferred Shares shall have the rights, designations and terms as set forth in the form of Certificate of Designations attached hereto as Annex I (the "Certificate of Designations"). The aggregate subscription price for the Preferred Shares shall be payable in United States Dollars. The shares of Common Stock issuable upon conversion of the Preferred Shares are referred to herein as the "Common Shares." The Common Shares and the Preferred Shares are referred to herein collectively as the "Shares." (b) Form of Payment. The Buyer shall pay the purchase price for the Preferred Shares by delivering good funds in United States Dollars to the escrow agent (the "Buyer Escrow Agent") identified in the Buyer Escrow Instructions attached hereto as Annex II (the "Buyer Escrow Instructions"). Such funds shall at all times remain the property of the Buyer, subject to the terms of the Buyer Escrow Instructions, until required to be released to the Company in accordance with the Buyer Escrow Instructions. Promptly, but in no event later than two New York Stock Exchange trading days, following receipt by the Company from the Buyer Escrow Agent of notice of payment by the Buyer to the Buyer Escrow Agent of the subscription price of the Preferred Shares, the Company shall deliver certificates for the Preferred Shares, registered in the name of the Buyer or as otherwise provided in Section 5 of this Agreement, to the escrow agent (the "Company Escrow Agent") identified in the Company Escrow Instructions attached hereto as Annex III (the "Company Escrow Instructions"). The Preferred Shares represented by such certificates shall at all times remain the property of the Company, subject to the terms of the Company Escrow Instructions, until required to be released to the Buyer in accordance with the Company Escrow Instructions; provided, however, that in no event shall the Company be entitled to exercise any voting rights or give any consent in respect of such Preferred Shares. By signing this Agreement, the Buyer agrees to all of the terms and conditions of, and becomes a party to, the Buyer Escrow Instructions, all of the provisions of which are incorporated herein by this reference as if set forth in full, and the Company agrees to all of the terms and conditions of, and becomes a party to, the Company Escrow Instructions, all of the provisions of which are incorporated herein by this reference as if set forth in full. Neither the Company nor any creditor or stockholder of the Company or any person claiming rights by, through or on behalf of the Company shall have any claim, lien, equity, encumbrance or other right to or in respect of the funds or any other property held pursuant to the Buyer Escrow Instructions prior to satisfaction of the conditions to the release thereof to the Company in accordance with the terms of this Agreement and the Buyer Escrow Instructions. Neither the Buyer nor any creditor or holder of an equity interest in the Buyer or any person claiming rights by, through or on behalf of the Buyer shall have any claim, lien, equity, encumbrance or other right to or in respect of the certificates for the Preferred Shares or any other property held pursuant to the Company Escrow Instructions prior to satisfaction of the conditions to the release thereof to the Buyer in accordance with the terms of this Agreement and the Company Escrow Instructions. (c) Method of Payment. Payment of the purchase price for the Preferred Shares shall be made by wire transfer of funds to: Citibank, N.A. 153 East 53rd Street New York, New York 10043 ABA#021000089 For Further Credit to A/C#37179446 for credit to the account of Brian W. Pusch Attorney Escrow Account Reference: ODA Fund I, Ltd./XOMA Not later than 4:00 p.m., New York City time, on the date which is two New York Stock Exchange trading days after the Company shall have accepted this Agreement and returned a signed counterpart of this Agreement to the Buyer, the Buyer shall deposit with the Buyer Escrow Agent the aggregate subscription price for the Preferred Shares. 2. BUYER REPRESENTATIONS, WARRANTIES, ETC.; ACCESS TO INFORMATION; INDEPENDENT INVESTIGATION. The Buyer represents and warrants to, and covenants and agrees with, the Company as follows: (a) The Buyer is purchasing the Preferred Shares for its own account for investment only and not with a view towards the public sale or distribution thereof; (b) The Buyer is an "accredited investor" as that term is defined in Rule 501 of the General Rules and Regulations under the 1933 Act by reason of Rule 501(a)(3); (c) All subsequent offers and sales of the Shares by the Buyer shall be made pursuant to registration of the Shares being offered and sold under the 1933 Act or pursuant to an exemption from registration; (d) The Buyer understands that the Preferred Shares are being offered and sold, and the Common Shares are being offered, to it in reliance on exemption from the registration requirements of the 1933 Act provided by Regulation D and exemptions from state securities laws, including exemptions available by reason of satisfying the requirements of Regulation D, and that the Company is relying upon the truth and accuracy of, and the Buyer's compliance with, the representations, warranties, agreements, acknowledgments and understandings of the Buyer set forth herein and in the Prospective Purchaser Questionnaire, a true and accurate copy of which has been delivered by the Buyer to the Company (the "Questionnaire"), in order to determine the availability of such exemptions and the eligibility of the Buyer to acquire the Preferred Shares and to receive an offer of the Common Shares; (e) The Buyer and its advisors, if any, have been furnished with all materials relating to the business, finances and operations of the Company and materials relating to the offer and sale of the Preferred Shares and the offer of the Common Shares which have been requested by the Buyer. The Buyer and its advisors, if any, have been afforded the opportunity to ask questions of the Company covering the terms of the offering of the Shares and the business, finances and operations of the Company and have received complete and satisfactory answers to any such inquiries. Without limiting the generality of the foregoing, the Buyer has had the opportunity to obtain and to review the Company's (1) Annual Report on Form 10-K for the fiscal year ended December 31, 1995 and Amendment No. 1 thereto on Form 10-K/A, filed March 26, 1996 and Amendment No. 2 thereto on Form 10-K/A, filed May 23, 1996, (2) Quarterly Reports on Form 10-Q for the fiscal quarters ended March 31, 1996 and June 30, 1996, (3) Current Report on Form 8-K, dated April 22, 1996, (4) Proxy Statement for its 1996 Annual Meeting of Stockholders, and (5) Registration Statement on Form S-3, filed with the SEC on June 28, 1996 (collectively, the "SEC Reports"), in each case as filed with the SEC. The Buyer understands that its investment in the Shares involves a high degree of risk; (f) The Buyer understands that no United States federal or state agency or any other government or governmental agency has passed on or made any recommendation or endorsement of the Shares; (g) This Agreement has been duly and validly authorized, executed and delivered on behalf of the Buyer and is a valid and binding agreement of the Buyer enforceable in accordance with its terms, subject as to enforceability to general principles of equity and to bankruptcy, insolvency, fraudulent conveyance, moratorium and other similar laws affecting the enforcement of creditors' rights generally and except that rights to indemnity and contribution may be limited by public policy; and (h) The Buyer understands that the Shares are being offered by the Company as part of an offering of shares of Series F Preferred Stock and Common Stock which may be greater than the number of Shares being purchased hereunder but that there is no minimum amount of the offering and that the Company may accept or reject this Agreement in its discretion. (i) Neither the Buyer (or any predecessor in interest to the Buyer) nor any person affiliated or associated with the Buyer (or any predecessor in interest to any such person) purchased any shares of Common Stock during the period from March 2, 1992 to June 3, 1992, inclusive. [(j) The purchase of the Preferred Shares by the Buyer pursuant to this Agreement does not require any governmental or regulatory consent, approval or filing on the part of the Buyer or, to the knowledge of the Buyer, on the part of the Company, under the securities or similar laws of the jurisdiction in which the Buyer's principal executive offices are located.] [TO BE INSERTED IF BUYER IS AN OFFSHORE ENTITY] 3. COMPANY REPRESENTATIONS, ETC. The Company represents and warrants to the Buyer that: (a) Organization and Authority. The Company is a corporation duly organized, validly existing and in good standing under the laws of the State of Delaware, and has all requisite corporate power and authority to (i) own, lease and operate its properties and to carry on its business as now being conducted, and (ii) to execute, deliver and perform its obligations under this Agreement, the Registration Rights Agreement, the form of which is attached hereto as Annex IV (the "Registration Rights Agreement"), the Certificate of Designations, and the other agreements executed and delivered by the Company in connection herewith, and to consummate the transactions contemplated hereby. The Company is duly qualified to do business as a foreign corporation and is in good standing in all jurisdictions wherein such qualification is necessary and where failure so to qualify could have a material adverse effect on the financial condition, results of operations, business or properties of the Company. (b) Capitalization. The authorized capital stock of the Company currently consists of (a) 70,000,000 shares of Common Stock, $.0005 par value per share, of which 34,324,669 shares were outstanding as of August 31, 1996 and all of which outstanding shares that are outstanding at the date hereof are fully paid and nonassessable and on the Closing Date (as defined herein) there will be no material increase from August 31, 1996 in the number of shares of Common Stock outstanding; and (b) 1,000,000 shares of Preferred Stock, $.05 par value per share, of which 650,000 shares are designated as Series A Cumulative Preferred Stock, none of which are outstanding, 7,500 shares are designated as Convertible Preferred Stock, Series E, none of which are outstanding, and of which up to 1,600 shares will be designated as Series F Preferred Stock. As of August 31, 1996, the Company had outstanding options to purchase 3,191,424 shares of Common Stock. The Company does not have outstanding any material amount of securities (or obligations to issue any such securities) convertible into, exchangeable for or otherwise entitling the holders thereof to acquire shares of Common Stock except as disclosed in the SEC Reports. The outstanding shares of Common Stock and outstanding options, warrants and other securities to purchase Common Stock have been duly authorized and validly issued. None of such outstanding shares of Common Stock, options, warrants and other securities has been issued in violation of the preemptive rights of any securityholder of the Company. The offers and sales of such outstanding shares of Common Stock, and outstanding options, warrants and other securities to purchase Common Stock were at all relevant times either registered under the 1933 Act and applicable state securities laws, or exempt from such registration requirements. The authorized shares of Common Stock, and outstanding options, warrants and other securities to purchase Common Stock conform to the descriptions thereof contained in the SEC Reports. No holder of any of the Company's securities has any rights, "demand," "piggy-back" or otherwise, to have such securities registered by reason of the intention to file, filing or effectiveness of the Registration Statement required to be filed pursuant to Section 2(a) of the Registration Rights Agreement. (c) Concerning the Shares and the Common Stock. The Shares have been duly authorized and the Preferred Shares, when issued, delivered and paid for in accordance with this Agreement, and the Common Shares, when issued on conversion of the Preferred Shares in accordance with the Certificate of Designations, as the case may be, will be duly and validly authorized and issued, fully paid and non-assessable and will not subject the holder thereof to personal liability by reason of being such holder. The Company has not granted any preemptive or similar rights which would entitle any stockholder of the Company or any other person to acquire the Shares. The Common Stock is listed for trading on the Nasdaq National Market ("Nasdaq") and (1) the Company and the Common Stock meet the criteria for continued listing and trading on Nasdaq; (2) the Company has not been notified since January 1, 1994 by the National Association of Securities Dealers, Inc. of any failure or potential failure to meet the criteria for continued listing and trading on Nasdaq and (3) no suspension of trading in the Common Stock is in effect. (d) Subscription Agreement; Registration Rights Agreement. This Agreement and the Registration Rights Agreement have been duly and validly authorized by the Company, this Agreement has been duly executed and delivered on behalf of the Company and, assuming the due authorization, execution and delivery hereof and thereof by the Buyer, this Agreement is, and the Registration Rights Agreement, when executed and delivered by the Company, will be, valid and binding agreements of the Company enforceable in accordance with their respective terms, subject as to enforceability to general principles of equity and to bankruptcy, insolvency, fraudulent conveyance, moratorium and other similar laws affecting the enforcement of creditors' rights generally and except that rights to indemnity and contribution may be limited by public policy. (e) Non-contravention. The execution and delivery of this Agreement and the Registration Rights Agreement by the Company and the consummation by the Company of the issuance of the Preferred Shares and the issuance of the Common Shares upon conversion of the Preferred Shares and the other transactions contemplated by this Agreement, the Registration Rights Agreement and the terms of the Series F Preferred Stock and the performance by the Company of its obligations thereunder do not and will not, with or without the giving of notice or the lapse of time, or both, conflict with or result in a breach or violation by the Company of any of the terms or provisions of, or constitute a default under, or result in the modification of, or result in the creation or imposition of any lien or other encumbrance upon any properties or assets of the Company pursuant to, the certificate of incorporation or by-laws of the Company, or any indenture, mortgage, deed of trust or other material agreement or instrument to which the Company is a party or by which it or any of its properties or assets are bound, or (assuming the representations and warranties of the Buyer in Section 2 hereof and in the Questionnaire, of the other buyers of shares of Series F Preferred Stock in the other Preferred Stock Subscription Agreements (collectively, the "Other Subscription Agreements") and Questionnaires executed by such other buyers, and of Carlyle International Securities (the "Placement Agent") in the letter to be delivered pursuant to Section 8(e) hereof are true and correct) any applicable law, rule or regulation or any applicable decree, judgment or order of any court, United States federal or state regulatory body, administrative agency or other governmental body having jurisdiction over the Company or any of its properties or assets, which conflict, breach, violation or default could have a material adverse effect on the validity or enforceability of this Agreement, the Registration Rights Agreement or the issuance of the Preferred Shares or the transactions contemplated by this Agreement, the Registration Rights Agreement or the terms of the Preferred Shares or on any right or remedy of the Buyer under this Agreement, the Registration Rights Agreement or the terms of the Preferred Shares. (f) Approvals. No authorization, approval or consent of, or filing with, any court, governmental body, regulatory agency, self-regulatory organization, or stock exchange or market or the stockholders of the Company is required to be obtained or made by the Company for the issuance and sale of the Shares as contemplated by this Agreement and the Certificate of Designations, other than (1) listing of the Common Shares on Nasdaq, (2) the filing of a Form D relating to the Common Shares by the Company with the SEC and (3) the requirements of any applicable blue sky laws. (g) Certain Environmental Matters. In September 1996, the Company received a notice from the U.S. Environmental Protection Agency ("EPA") that the Company may have incurred or may incur liability under the Comprehensive Environmental Response, Compensation and Liability Act in connection with the RAMP Industries, Inc. site in Denver, Colorado. The notice indicates that the Company is one of approximately 690 parties to receive the same notice and that, to date, EPA has identified between 1 and 3 barrels of the approximately 6,000 barrels located at the site when EPA began clean up as being attributable to the Company. The notice also states that EPA does not anticipate proposing this site for listing on the National Priorities List of Superfund Sites. Although the Company has not yet completed its review of this matter, it has no reason to believe at the date hereof that the outcome of this matter will have a material adverse effect on its financial condition or results of operations. (h) Information Provided. The information provided by or on behalf of the Company to the Buyer and referred to in Section 2(e) of this Agreement and the information set forth in Section 3(g) of this Agreement does not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they are made, not misleading. (i) Absence of Certain Changes. Since December 31, 1995, there has been no material adverse change and no material adverse development in the business, properties, operations, financial condition or results of operations of the Company, except as disclosed in the documents referred to in Section 2(e) hereof. (j) Absence of Litigation. Except (i) as set forth in the SEC Reports and as disclosed in Section 3(g) hereof, and (ii) for applications and proceedings relating to regulatory approval of new drugs or the granting of patents, there is no action, suit, proceeding, inquiry or investigation before or by any court, public board or body pending or, to the knowledge of the Company, threatened against or affecting the Company, wherein an unfavorable decision, ruling or finding would have a material adverse effect on the properties, business, condition (financial or other) or results of operations of the Company or the transactions contemplated by this Agreement or any of the documents contemplated hereby or which would materially adversely affect the validity or enforceability of, or the authority or ability of the Company to perform its obligations under, this Agreement or any of such other documents. (k) Properties. The Company has good title to all property real and personal (tangible and intangible) and other assets owned by it, free and clear of all security interests, charges, mortgages, liens or other encumbrances, except such as are described in the SEC Reports or such as do not materially interfere with the use of such property made, or proposed to be made, by the Company. The leases, licenses or other contracts or instruments under which the Company leases, holds or is entitled to use any property, real or personal, are valid, subsisting and enforceable only with such exceptions as do not materially interfere with the use of such property made, or proposed to be made, by the Company. The Company has not received notice of any material violation of any applicable law, ordinance, regulation, order or requirement relating to its owned or leased properties. (l) Labor Relations. No material labor problem exists or, to the knowledge of the Company, is imminent with respect to any of the employees of the Company. (m) SEC Filings. The Company has timely filed all required forms, reports and other documents with the SEC. All of such forms, reports and other documents complied, when filed, in all material respects, with all applicable requirements of the 1933 Act and the Securities Exchange Act of 1934, as amended (the "1934 Act"). (n) Transfer Agent. The Company has used, and the Company's transfer agent has accepted, instructions and opinions in substantially the forms attached as Exhibits 1 and 2 to the Registration Rights Agreement in connection with the Company's Non-Voting Cumulative Convertible Preferred Stock, Series D, and the Company has no reason to believe that such transfer agent will not find acceptable and sufficient instructions and opinions in such form in connection with the Series F Preferred Stock. 4. CERTAIN COVENANTS AND ACKNOWLEDGMENTS. (a) Transfer Restrictions. The Buyer acknowledges that (1) the Preferred Shares to be issued to it hereunder have not been and are not being registered under the provisions of the 1933 Act and, except as provided in the Registration Rights Agreement, the Common Shares have not been and are not being registered under the 1933 Act, and the Preferred Shares may not be transferred unless (A) the Preferred Shares to be transferred are subsequently registered thereunder for resale by the Buyer or (B) the Buyer shall have delivered to the Company an opinion, reasonably satisfactory in form, scope and substance to the Company, of counsel reasonably satisfactory to the Company (which shall include, but not be limited to, counsel who represented the Buyer in connection with the negotiation and execution of this Agreement) to the effect that the Preferred Shares to be sold or transferred may be sold or transferred pursuant to an exemption from such registration; (2) any sale of the Shares made in reliance on Rule 144 promulgated under the 1933 Act may be made only in accordance with the terms of said Rule and further, if said Rule is not applicable, any resale of such Shares under circumstances in which the seller, or the person through whom the sale is made, may be deemed to be an underwriter, as that term is used in the 1933 Act, may require compliance with some other exemption under the 1933 Act or the rules and regulations of the SEC thereunder; and (3) neither the Company nor any other person is under any obligation to register the Shares (other than registration of the Common Shares pursuant to the Registration Rights Agreement) under the 1933 Act or to comply with the terms and conditions of any exemption thereunder. (b) Restrictive Legend. The Buyer acknowledges and agrees that the certificates for the Preferred Shares may bear a restrictive legend in substantially the following form (and a stop-transfer order may be placed against transfer of the certificates for the Preferred Shares): The securities represented by this certificate have not been registered under the Securities Act of 1933, as amended, or any state securities laws. The securities have been acquired for investment and may not be sold, transferred or assigned in the absence of (1) an effective registration statement for these shares under the Securities Act of 1933, as amended, or an opinion reasonably satisfactory in form, scope and substance to the Company of counsel reasonably satisfactory to the Company that registration is not required under said Act and (2) registration under or compliance with such state securities laws. (c) Registration Rights Agreement. The parties hereto agree to enter into the Registration Rights Agreement, in the form attached hereto as Annex IV, on or before the Closing Date. (d) Form D. The Company agrees to file a Form D with respect to the Shares as required under Regulation D and to provide a copy thereof to the Buyer promptly after such filing. The Buyer agrees to cooperate with the Company in connection with such filing and, upon request of the Company, to provide all information relating to the Buyer required for such filing. (e) Nasdaq Listing; Reporting Status. Promptly but in no event later than five business days following the Closing Date, the Company will file with Nasdaq an application or other document required by Nasdaq for the listing of the Common Shares with Nasdaq and shall provide evidence of such filing to the Buyer. So long as the Buyer beneficially owns any of the Preferred Shares or the Common Shares, the Company shall file all reports required to be filed with the SEC pursuant to Section 13 or 15(d) of the 1934 Act, and the Company shall not terminate its status as an issuer required to file reports under the 1934 Act even if the 1934 Act or the rules and regulations thereunder would permit such termination. The Company will use its commercially reasonable efforts to maintain the listing of the Common Stock on Nasdaq or another national securities exchange for at least six months following the latest date of conversion of Preferred Shares. (f) Use of Proceeds. The Company will use the proceeds from the sale of the Preferred Shares for internal working capital and shall not, directly or indirectly, use such proceeds for any loan to or investment in any other corporation, partnership enterprise or other person; provided, however, that nothing in this Section 4(f) shall prohibit the Company from using such proceeds for the acquisition of or investment in businesses, product lines or technologies in the fields of research, development or marketing of pharmaceutical products for the treatment of human and animal diseases and illnesses or from making any loan to any business engaged in such activity and in which the Company owns an interest having a majority of the voting or similar power of such business. (g) Blue Sky Laws. On or before the Closing Date, the Company shall take such action as shall be necessary to qualify, or to obtain an exemption for, the Preferred Shares for sale to the Buyer pursuant to this Agreement and the Common Shares for sale to the Buyer on conversion of the Preferred Shares under such of the securities or "blue sky" laws of jurisdictions in the United States as shall be applicable to the sale of the Preferred Shares to the Buyer pursuant to this Agreement and issuance of the Common Shares on conversion of the Preferred Shares. The Company shall furnish to the Buyer copies of all filings, applications, orders and grants or confirmations of exemptions relating to such securities or "blue sky" laws on or before the Closing Date. The Buyer agrees to cooperate with the Company in connection with such actions and, upon request of the Company, to provide all information, if any, concerning the Buyer required for such actions. (h) Limitation on Certain Sales of Common Shares. The Buyer agrees that, except as hereinafter provided, the Buyer shall not make open market sales of more than [BEFORE SIGNING INSERT PRO RATA PORTION OF 375,000] Common Shares (such amount to be subject to equitable adjustment from time to time for stock splits, stock dividends, combinations, capital reorganizations and similar events relating to the Common Stock occurring on or after the date of this Agreement) during any calendar week, unless otherwise agreed to in advance by the Company. Amounts of Common Shares not sold in any calendar week shall not be cumulative and may not be carried forward to any future calendar week. Notwithstanding the foregoing, if on or after the date on which the Registration Statement required to be filed by the Company with the SEC pursuant to Section 2(a) of the Registration Rights Agreement is first declared effective by the SEC (the "SEC Effective Date") the arithmetic average of the Closing Prices (as defined herein) during any period of five consecutive trading days is 20% or more above the Closing Price on the trading day immediately preceding such five-day period then, during the period of ten consecutive trading days immediately following such five-day period the foregoing restriction on the amount of Common Shares which may be sold by the Buyer shall be inapplicable. If any such ten-day period shall end on any day other than a Friday, then, during the portion of such calendar week after such ten-day period, the Buyer shall not make open market sales of Common Shares in an amount in excess of an amount equal to the product obtained by multiplying (1) [BEFORE SIGNING INSERT PRO RATA PORTION OF 75,000] Common Shares (such amount to be subject to equitable adjustment from time to time for stock splits, stock dividends, combinations, capital reorganizations and similar events relating to the Common Stock occurring on or after the date of this Agreement) times (2) the number of trading days in such calendar week falling after the last day in such ten-day period. As used herein, the "Closing Price" on any date shall mean (i) if the Common Stock is listed on a national securities exchange, the last reported bid price per share of the Common Stock on the principal securities exchange on which the Common Stock is listed that shall be consolidated for consolidated trading, if applicable to such exchange, on such date, or (ii) if the Common Stock is not so listed, the last reported bid price per share of the Common Stock as reported on Nasdaq on such date, or (iii) if the Common Stock is neither so listed nor so reported, the last reported bid price per share of the Common Stock as quoted by a registered broker-dealer on such date; provided that such quotes must have been available for at least five days in the preceding thirty-day period, or (iv) if the Common Stock is not so listed, so reported or so quoted, the fair value of the Common Stock on such date, as reasonably determined by the Board of Directors of the Company in good faith after taking into account such factors as the Board of Directors of the Company may deem appropriate, including one or more professional valuations. Notwithstanding the foregoing limitation, the Buyer shall be permitted to tender all or any portion of the Common Shares in connection with any tender offer or exchange offer for outstanding shares of Common Stock. (i) Certain Future Financings. The Company shall not issue any equity securities or securities convertible into, exchangeable for or otherwise entitling the holder to acquire, any equity securities of the Company during the period from the date of acceptance of this Agreement by the Company to the date which is 90 days after the SEC Effective Date without the prior written consent of the Buyer (which consent shall not be unreasonably withheld or delayed); provided, however, that nothing in this Section 4(i) shall prohibit the Company from issuing securities (x) as part of a transaction involving a strategic alliance, collaboration, joint venture, partnership or other similar arrangement of the Company, (y) pursuant to compensation plans for employees, directors, officers, advisers or consultants of the Company or (z) upon exercise of conversion, exchange, purchase or similar rights issued, granted or given by the Company and outstanding as of the date of this Agreement. (j) Certain Information. From the date hereof to the SEC Effective Date, the Company shall provide to Och-Ziff Capital Management L.L.C. information concerning all material developments relating to the matter described in Section 3(g) hereof of which the Company has knowledge during such period. 5. TRANSFER OF PREFERRED SHARES; CONVERSION PROCEDURE. (a) Limitation on Transfer Agent Instructions; Certain Transfers. The Company warrants that no instruction contrary to the instructions referred to in Section 3(l) of the Registration Rights Agreement will be given by the Company to the Company's transfer agent for the Common Stock with respect to the Common Shares and that the Common Shares shall otherwise be freely transferable on the books and records of the Company as and to the extent provided in the Registration Rights Agreement. If the Buyer provides the Company with an opinion of counsel that registration of a proposed resale by the Buyer of any of the Preferred Shares is not required under the 1933 Act and which opinion otherwise meets the requirements of clause (1)(B) of Section 4(a) of this Agreement and such proposed transfer otherwise meets the requirements of the Certificate of Designations, the Company shall permit the transfer of such Preferred Shares. (b) Conversion Procedure. In connection with the exercise of conversion rights relating to the Preferred Shares, the Buyer shall complete, sign and furnish to the Company by personal delivery, courier or telephone line facsimile transmission (in each case to be effective on receipt and in the case of telephone line facsimile transmission, the original conversion certificate shall promptly be sent to the Company by overnight courier service) a conversion certificate in the form attached hereto as Annex V, which shall satisfy the requirements of Section 8(c) of the Certificate of Designations. 6. STOCK DELIVERY INSTRUCTIONS. The certificates for the Preferred Shares shall be delivered by the Company to the Company Escrow Agent pursuant to Section 1(b) hereof on a delivery against payment basis upon release from escrow in accordance with Section 7(b). 7. CLOSING DATE; ESCROW RELEASES. (a) The date and time of the issuance and sale of the Preferred Shares (the "Closing Date") shall be 12:00 noon, New York City time, on the date which is two New York Stock Exchange trading days after the date on which the Buyer has deposited the aggregate subscription price for the Preferred Shares with the Buyer Escrow Agent in accordance with Section 1(c) hereof, or such other mutually agreed to time. The closing shall occur on the Closing Date at the Law Offices of Brian W Pusch, Penthouse Suite, 29 West 57th Street, New York, New York. The Buyer and the Company agree that, upon completion of the closing on the Closing Date, the Preferred Shares shall be deemed to be outstanding for all purposes and the escrow created by the Company Escrow Instructions shall serve so that all acts necessary for the issuance of the Preferred Shares shall be deemed to have occurred on the Closing Date and only delivery of the Preferred Shares to the Buyer shall not have occurred; provided, however, that the Preferred Shares shall not be deemed fully paid until the purchase price therefor as provided in this Agreement shall have been released to the Company from the escrow created by the Buyer Escrow Instructions, which release shall occur only as provided herein, and the Buyer shall have no liability for payment of such purchase price other than in accordance with the Buyer Escrow Instructions. (b)(1) Promptly after the SEC Effective Date, the Company shall notify the Buyer (the "Company Notice") that the SEC Effective Date has occurred. Promptly, but in no event later than two New York Stock Exchange trading days after the Company Notice has been given to the Buyer, the Company shall notify the Company Escrow Agent that the SEC Effective Date has occurred. If (A) no Insolvency Event (as defined herein) shall have occurred and be continuing; (B) the representations and warranties of the Company in this Agreement made on the date of this Agreement and on the Closing Date shall have been true and correct in all material respects on the date of this Agreement and on the Closing Date; (C) the Company shall have performed on or before the SEC Effective Date all covenants and agreements of the Company required to be performed on or before the SEC Effective Date; (D) the Company shall have furnished to the Buyer a written opinion, dated the SEC Effective Date, addressed to the Buyer, of Cahill Gordon & Reindel, special counsel for the Company substantially in the form attached hereto as Annex VI and a written statement of Christopher J. Margolin, Vice President, General Counsel and Secretary of the Company substantially in the form attached hereto as Annex VII ; and (E) the Company shall have furnished to the Buyer a certificate of the Company, dated the SEC Effective Date, signed by any two of the five executive officers of the Company, to the effect that the signers of such certificate have examined the Registration Statement and related prospectus and this Agreement and that: (i) the representations and warranties of the Company in this Agreement made on the date of this Agreement and on the Closing Date were true and correct in all material respects on the date of this Agreement and on the Closing Date, and the Company has performed on or before the SEC Effective Date all covenants and agreements of the Company required to be performed on or before the SEC Effective Date; and (ii) no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose have been instituted or, to the Company's knowledge, threatened by the SEC. then promptly, but in no event later than two New York Stock Exchange trading days after the later of (x) the date the Company Notice has been given to the Buyer, and (y) the date of delivery to the Buyer of the documents specified in the foregoing clauses (D) and (E), the Buyer shall notify the Buyer Escrow Agent that (1) the SEC Effective Date has occurred and (2) all conditions precedent to the release of the portion of the Escrow Funds (as defined in the Buyer Escrow Instructions) to be released to the Company have been satisfied or waived. The Company and the Buyer agree that, on the latest of (1) the date of receipt by the Company Escrow Agent of such notice from the Company, (2) the date of receipt by the Buyer Escrow Agent of such notice from the Buyer, (3) the date of receipt by the escrow agent acting on behalf of the Company in connection with the Other Subscription Agreements of the latest of the notices from the Company to release the securities held by such escrow agents to the buyers under the Other Subscription Agreements, and (4) the date of receipt by the escrow agent acting on behalf of the buyers in connection with the Other Subscription Agreements of the latest of the notices from such buyers to release funds held by such escrow agents to the Company, or as promptly as practicable thereafter, the certificate(s) for the Preferred Shares shall be released to the Buyer in accordance with Section 1 of the Company Escrow Instructions and the portion of the Escrow Funds to be released to the Company shall be released to the Company in accordance with Section 1 of the Buyer Escrow Instructions. (2) As used herein, the term "Insolvency Event" means (A) a decree or order for relief by a court having jurisdiction in the premises shall have been entered in respect of the Company in an involuntary case under the federal bankruptcy laws, as now or hereafter constituted, or any other applicable federal or state bankruptcy, insolvency or other similar law, including any such decree or order appointing a custodian or receiver or liquidator or trustee or assignee of the Company or of all or a major part of its property, or for the winding-up or liquidation of its affairs (or any petition seeking such decree or order shall have been filed with such a court and shall not have been withdrawn or dismissed); or (B) the Company shall commence a voluntary case under the federal bankruptcy laws, as now or hereafter constituted, or any other applicable federal or state bankruptcy, insolvency or other similar law, or shall consent to the appointment of or taking possession by a custodian or receiver or liquidator or trustee or assignee of the Company or of all or a major part of its property, or shall make an assignment for the benefit of creditors. (3) Notwithstanding any other provision of this Agreement or any of the other documents contemplated hereby, if on the date on which the Escrow Funds are to be released to the Company and the certificate(s) for the Preferred Shares are to be released to the Buyer any Preferred Shares would not, by reason of the provisions of Section 8(d)(1) of the Certificate of Designations, be convertible into shares of Common Stock had all Preferred Shares been surrendered for conversion into Common Stock on such date (determined without regard to the proviso to the second sentence of Section 8(a) of the Certificate of Designations), then the number of Preferred Shares to be released to the Buyer from the escrow created by the Company Escrow Instructions shall be reduced pro rata with all other outstanding shares of Series F Preferred Stock and shares of Series F Preferred Stock which the Company has so agreed to issue and the amount of Escrow Funds to be released to the Company shall be reduced accordingly so that the provisions of Section 8(d)(1) of the Certificate of Designations would not so limit the conversion of any such shares of Series F Preferred Stock on such date. If the provisions of this Section 7(b)(3) become applicable, the Company shall instruct the Company Escrow Agent to reduce the number of Preferred Shares to be released to the Buyer as provided herein (and shall arrange to subdivide appropriately the certificate(s) for Preferred Shares held by the Company Escrow Agent to permit such reduction), to release such reduced number of Preferred Shares to the Buyer and to release the balance of the shares of Series F Preferred Stock held by the Company Escrow Agent to the Company, and the Buyer shall instruct the Buyer Escrow Agent to reduce the amount of the Escrow Funds to be released to the Company as provided herein, to release such reduced amount of Escrow Funds to the Company and to release the balance of the Escrow Funds to the Buyer. (c) If the SEC Effective Date does not occur within 90 days after the Closing Date, the Buyer shall have the right, exercisable by notice to the Company pursuant to this Agreement and to the Buyer Escrow Agent pursuant to the Buyer Escrow Instructions given at any time prior to the SEC Effective Date, to terminate the escrow under the Buyer Escrow Instructions as to all or any portion of the Preferred Shares, whereupon, the Company shall be entitled to release of the certificates for the Preferred Shares as to which the escrow created by the Buyer Escrow Instructions is to be so terminated from the escrow created by the Company Escrow Instructions and the Buyer shall be entitled to release of an amount equal to all or such portion of the subscription price for the Preferred Shares as to which the escrow created by the Buyer Escrow Instructions is to be so terminated, together with interest thereon as contemplated by the Buyer Escrow Instructions, from the escrow created by the Buyer Escrow Instructions, and (x) if the Buyer has so notified the Company and the Buyer Escrow Agent that it wishes to terminate the escrow created by the Buyer Escrow Instructions with respect to all of the Preferred Shares, then the Company and the Buyer shall have no further obligations or liabilities to one another under this Agreement or in connection with the transactions contemplated hereby and (y) if the Buyer has so notified the Company and the Buyer Escrow Agent that it wishes to terminate the escrow created by the Buyer Escrow Instructions with respect to a portion of the Preferred Shares, then the Company and the Buyer shall have no further obligations or liabilities to one another in respect of the Preferred Shares as to which the escrow created by the Buyer Escrow Instructions is so terminated under this Agreement or in connection with the transactions contemplated hereby. If the Buyer exercises its right to terminate the escrow created by the Buyer Escrow Instructions with respect to a portion of the Preferred Shares, then the Company shall promptly deliver to the Company Escrow Agent a substitute certificate or certificates for Preferred Shares in such denomination or denominations as shall be required to accommodate the reduction in the number of Preferred Shares to be released to the Buyer from the escrow created by the Company Escrow Instructions. 8. CONDITIONS TO THE COMPANY'S OBLIGATION TO SELL AND ISSUE. The Buyer understands that the Company's obligation to sell the Preferred Shares to the Buyer pursuant to this Agreement is conditioned upon: (a) The receipt and acceptance by the Company of the Buyer's subscription for the Preferred Shares as evidenced by execution of this Agreement by the Company and the return of an executed copy hereof to the Buyer or its legal counsel; (b) Delivery by the Buyer to the Buyer Escrow Agent of good funds as payment in full of an amount equal to the subscription price for the Preferred Shares in accordance with Section 1(c) hereof; (c) No legal action, suit or proceeding shall be pending or threatened which (i) demands damages for any alleged liability asserted to arise by reason of the transaction contemplated by this Agreement and/or (ii) seeks to restrain or prohibit the transactions contemplated by this Agreement; (d) The accuracy on the Closing Date of the representations and warranties of the Buyer contained in this Agreement and in the Questionnaire as if made on the Closing Date and the performance by the Buyer on or before the Closing Date of all covenants and agreements of the Buyer required to be performed on or before the Closing Date; and (e) The Company shall have received a letter, dated the Closing Date, from the Placement Agent addressed to the Company in the form attached hereto as Annex VIII. 9. CONDITIONS TO THE BUYER'S OBLIGATION TO PURCHASE. The Company understands that the Buyer's obligation to purchase the Preferred Shares is conditioned upon: (a) Delivery by the Company to the Company Escrow Agent of the certificates for the Preferred Shares in accordance with this Agreement; (b) No legal action, suit or proceeding shall be pending or threatened which (i) demands damages for any alleged liability asserted to arise by reason of the transaction contemplated by this Agreement and/or (ii) seeks to restrain or prohibit the transactions contemplated by this Agreement; (c) The accuracy on the Closing Date of the representations and warranties of the Company contained in this Agreement as if made on the Closing Date and the performance by the Company on or before the Closing Date of all covenants and agreements of the Company required to be performed on or before such Closing Date; (d) The receipt by the Buyer of confirmation of the filing with the Secretary of State of the State of Delaware of the Certificate of Designations in the form attached hereto as Annex I; and (e) On the Closing Date, the Buyer having received opinions of counsel for the Company, dated the Closing Date, substantially in the forms of Annex IX and Annex X attached hereto. 10. MISCELLANEOUS. (a) This Agreement shall be governed by and interpreted in accordance with the laws of the State of California without regard to principles of conflicts of laws. (b) This Agreement may be executed in counterparts and by the parties hereto on separate counterparts, all of which together shall constitute one and the same instrument. A facsimile transmission of this signed Agreement bearing a signature on behalf of a party hereto shall be legal and binding on such party. (c) The headings and captions of this Agreement are for convenience of reference and shall not form part of, or affect the interpretation of, this Agreement. (d) If any provision of this Agreement shall be invalid or unenforceable in any jurisdiction, such invalidity or unenforceability shall not affect the validity or enforceability of the remainder of this Agreement or the validity or enforceability of this Agreement in any other jurisdiction. (e) This Agreement may be amended only by an instrument in writing signed by the party to be charged with enforcement. (f) Any notices required or permitted to be given under the terms of this Agreement shall be in writing and shall be delivered personally (which shall include telephone line facsimile transmission) or by courier and shall be effective upon receipt, in each case addressed to a party at such party's address shown in the introductory paragraph or on the signature page of this Agreement (facsimile number (510) 649-7571, in the case of the Company, and facsimile number ______________, in the case of the Buyer) or such other address as a party shall have provided by notice to the other party in accordance with this provision. The Buyer hereby designates as its address and telephone line facsimile number for any notice required or permitted to be given to the Buyer pursuant to the Certificate of Designations the address and facsimile number shown on the signature page of this Agreement, until the Buyer shall designate another address or telephone line facsimile number for such purpose by notice to the Company. (g) This Agreement shall be binding on the parties hereto and their respective successors and permitted assigns. Neither the Company nor the Buyer may assign its rights or obligations under this Agreement without the prior written consent of the other party hereto. (h) Failure of any party to exercise any right or remedy under this Agreement or otherwise, or delay by a party in exercising such right or remedy, shall not operate as a waiver thereof, nor shall any single or partial exercise of any such right or power, or any abandonment or discontinuance of steps to enforce such a right or power, preclude any other or further exercise thereof or exercise of any other right or power. IN WITNESS WHEREOF, this Agreement has been duly executed by the Buyer or one of its officers thereunto duly authorized as of the date set forth below. NUMBER OF SHARES OF SERIES F PREFERRED STOCK: __________ PRICE PER SHARE: $10,000.00 AGGREGATE SUBSCRIPTION PRICE: $_______________ For purposes of Section 8(a) of the Certificate of Designations, the Buyer hereby agrees to the following percentage as the Buyer's Restriction Percentage: Please Check One: --- /__/ 4.9 percent --- /__/ 9.9 percent If no box is checked, there will be no such limit. NAME OF BUYER: ______________________ SIGNATURE ____________________________ Title: _______________________________ Date: _______________________________ Address: __________________________ __________________________ __________________________ Facsimile Number: ____________________ This Agreement has been accepted as of the date set forth below. XOMA CORPORATION By: ______________________________ Peter Davis Vice President, Finance and Chief Financial Officer Date: ____________________________