Annex III to Preferred Stock Subscription Agreement REGISTRATION RIGHTS AGREEMENT THIS REGISTRATION RIGHTS AGREEMENT, dated as of March 29, 1996 (this "Agreement"), is made by and between XOMA CORPORATION, a Delaware corporation (the "Company"), and the person named on the signature page hereto (the "Initial Investor"). W I T N E S S E T H: WHEREAS, in connection with the Preferred Stock Subscription Agreement, dated as of March 27, 1996, between the Initial Investor and the Company (the "Subscription Agreement"), the Company has agreed, upon the terms and subject to the conditions of the Subscription Agreement, to issue and sell to the Initial Investor shares (the "Preferred Shares") of Non-Voting Cumulative Convertible Preferred Stock, Series D, $.05 par value (the "Preferred Stock"), of the Company, which Preferred Shares shall be convertible into shares (the "Conversion Shares") of Common Stock, $.0005 par value (the "Common Stock"), of the Company in accordance with the Certificate of Designations pursuant to Section 151 of the General Corporation Law of the State of Delaware relating to the Preferred Stock (the "Certificate of Designations"); WHEREAS, to induce the Initial Investor to execute and deliver the Subscription Agreement, the Company has agreed to provide certain registration rights under the Securities Act of 1933, as amended, and the rules and regulations thereunder, or any similar successor statute (collectively, the "Securities Act"), and applicable state securities laws with respect to the Conversion Shares; 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 Company and the Initial Investor hereby agree as follows: 1. Definitions. (a) As used in this Agreement, the following terms shall have the following meanings: (i) "Investor" means the Initial Investor and any transferee or assignee who is a Permitted Transferee (as defined in Section 9 hereof) and agrees to become bound by the provisions of this Agreement in accordance with Section 9 hereof. (ii) "register," "registered," and "registration" refer to a registration effected by preparing and filing a Registration Statement or Statements in compliance with the Securities Act and pursuant to Rule 415 under the Securities Act or any successor rule providing for offering securities on a continuous basis ("Rule 415"), and the declaration or ordering of effectiveness of such Registration Statement by the United States Securities and Exchange Commission (the "SEC"). (iii) "Registrable Securities" means the Conversion Shares and any shares of Common Stock issued by the Company to any Investor in payment of dividends on the Preferred Shares, in each case together with the related Preferred Stock Purchase Rights. (iv) "Registration Statement" means a registration statement of the Company under the Securities Act. (b) Capitalized terms defined in the introductory paragraph of or the recitals to this Agreement have the respective meanings provided therein. Capitalized terms used herein and not otherwise defined herein shall have the respective meanings set forth in the Subscription Agreement. 2. Registration. (a) Mandatory Registration. The Company shall prepare, and on or prior to the date which is 30 days after the date of the closing under the Subscription Agreement (the "Closing Date"), file with the SEC a Registration Statement on Form S-3 covering at least 2,272,728 shares of Common Stock as Registrable Securities, and which Registration Statement shall state that, in accordance with Rule 416 under the Securities Act, such Registration Statement also covers such indeterminate number of additional shares of Common Stock as may become issuable upon conversion of the Preferred Shares to prevent dilution resulting from stock splits, stock dividends or similar transactions or by reason of changes in the conversion price of the Preferred Shares in accordance with the terms thereof. If at any time the number of shares included in the Registration Statement required to be filed as provided in the first sentence of this Section 2(a) shall not be sufficient to cover the number of shares of Common Stock issuable on conversion -2- in full of the unconverted Preferred Shares, then promptly, but in no event later than 15 days after such insufficiency shall occur, the Company shall file with the SEC an additional Registration Statement on Form S-3 or other applicable form covering such number of shares of Common Stock as shall be sufficient to permit such conversion and exercise. For all purposes of this Agreement (other than Section 2(b) hereof) such additional Registration Statement shall be deemed to be the Registration Statement required to be filed by the Company pursuant to Section 2(a) of this Agreement, and the Company and the Investors shall have the same rights and obligations (other than Section 2(b) hereof) with respect to such additional Registration Statement as they shall have with respect to the initial Registration Statement required to be filed by the Company pursuant to this Section 2(a). (b) Reduction of Conversion Price. If the Registration Statement covering the Registrable Securities required to be filed by the Company pursuant to Section 2(a) hereof is not effective within 90 days after the Closing Date, then the conversion price of the Preferred Stock shall be reduced as provided in the Certificate of Designations subject to the right of the Company to make cash payments in lieu thereof as provided in the Certificate of Designations. (c) Piggy-Back Registrations. If at any time the Company shall determine to prepare and file with the SEC a Registration Statement relating to an offering for its own account or the account of others under the Securities Act of any of its equity securities, other than on Form S-4 or Form S-8 or their then equivalents relating to equity securities to be issued solely in connection with any acquisition of any entity or business or equity securities issuable in connection with stock option or other employee benefit plans, the Company shall send to each Investor who is entitled to registration rights under this Section 2(c) written notice of such determination and, if within ten (10) days after receipt of such notice, such Investor shall so request in writing, the Company shall include in such Registration Statement all or any part of the Registrable Securities such Investor requests to be registered, except that if, in connection with any underwritten public offering for the account of the Company the managing underwriter(s) thereof shall impose a limitation on the number of shares of Common Stock which may be included in the Registration Statement because, in such underwriter(s)' judgment, such limitation is necessary to effect an orderly public distribution, then the Company shall be obligated to include in such Registration Statement only such limited portion of the Registrable Securities with respect to which such Investor has requested inclusion hereunder. Any exclusion of Registrable Securities shall be made -3- pro rata among the Investors seeking to include Registrable Securities, in proportion to the number of Registrable Securities sought to be included by such Investors; provided, however, that the Company shall not exclude any Registrable Securities unless the Company has first excluded all outstanding securities the holders of which are not entitled by right to inclusion of securities in such Registration Statement; and provided further, however, that, after giving effect to the immediately preceding proviso, any exclusion of Registrable Securities shall be made pro rata with holders of other securities having the right to include such securities in the Registration Statement, based on the number of securities for which registration is requested. No right to registration of Registrable Securities under this Section 2(c) shall be construed to limit any registration required under Section 2(a) hereof. The obligations of the Company under this Section 2(c) may be waived by Investors holding a majority in interest of the Registrable Securities and shall expire after the Company has afforded the opportunity for the Investors to exercise registration rights under this Section 2(c) for two registrations; provided, however, that any Investor who shall have had any Registrable Securities excluded from any Registration Statement in accordance with this Section 2(c) shall be entitled to include in an additional Registration Statement filed by the Company the Registrable Securities so excluded. Notwithstanding any other provision of this Agreement, if the Registration Statement required to be filed pursuant to Section 2(a) of this Agreement shall have been ordered effective by the SEC and the Company shall have maintained the effectiveness of such Registration Statement as required by this Agreement and if the Company shall otherwise have complied in all material respects with its obligations under this Agreement and the terms of the Preferred Shares, then the Company shall not be obligated to register any Registrable Securities on such Registration Statement referred to in this Section 2(c). (d) Eligibility for Form S-3. The Company represents and warrants that it meets the requirements for the use of Form S-3 for registration of the sale by the Initial Investor and any Investor of the Registrable Securities and the Company shall file all reports required to be filed by the Company with the SEC in a timely manner so as to maintain such eligibility for the use of Form S-3 for so long as the Company is required to maintain effectiveness of the Registration Statement in accordance with Section 3(a). 3. Obligations of the Company. In connection with the registration of the Registrable Securities, the Company shall: (a) prepare promptly, and file with the SEC not later -4- than 30 days after the Closing Date, a Registration Statement with respect to the number of Registrable Securities provided in Section 2(a), and thereafter to use its commercially reasonable best efforts to cause each Registration Statement relating to Registrable Securities to become effective as soon as practicable after such filing, and keep the Registration Statement effective pursuant to Rule 415 at all times until such date as is three years after the Closing Date (or, if all of the Preferred Shares have been converted into shares of Common Stock, such date after which each Investor may sell all Registrable Securities without registration under the Securities Act pursuant to Rule 144 promulgated under the Securities Act or any other similar rule or regulation of the SEC that may at any time permit the Investors to sell securities of the Company to the public without registration ("Rule 144"), free of any limitation on the volume of such securities which may be sold in any period, which Registration Statement (including any amendments or supplements thereto and prospectuses contained therein) shall not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein, or necessary to make the statements therein, in light of the circumstances in which they were made, not misleading; (b) prepare and file with the SEC such amendments (including post-effective amendments) and supplements to the Registration Statement and the prospectus used in connection with the Registration Statement as may be necessary to keep the Registration Statement effective at all times until such date as is three years after the Closing Date (or such earlier date as shall be permitted under Section 3(a)), and, during such period, comply with the provisions of the Securities Act with respect to the disposition of all Registrable Securities of the Company covered by the Registration Statement until such time as all of such Registrable Securities have been disposed of in accordance with the intended methods of disposition by the seller or sellers thereof as set forth in the Registration Statement; (c) furnish to each Investor whose Registrable Securities are included in the Registration Statement and its legal counsel, (1) promptly after the same is prepared and publicly distributed, filed with the SEC or received by the Company, one copy of the Registration Statement and any amendment thereto, each preliminary prospectus and prospectus and each amendment or supplement thereto, each letter written by or on behalf of the Company to the SEC or the staff of the SEC and each item of correspondence from the SEC or the staff of the SEC relating to such Registration Statement (other than any portion of any thereof which contains information for which the Company has sought confidential treatment) and (2) -5- such number of copies of a prospectus, including a preliminary prospectus, and all amendments and supplements thereto and such other documents, as such Investor may reasonably request in order to facilitate the disposition of the Registrable Securities owned by such Investor; (d) use commercially reasonable best efforts to (i) register and qualify the Registrable Securities covered by the Registration Statement under such securities or blue sky laws of such jurisdictions as the Investors who hold a majority in interest of the Registrable Securities being offered reasonably request, (ii) prepare and file in those jurisdictions such amendments (including post-effective amendments) and supplements to such registrations and qualifications as may be necessary to maintain the effectiveness thereof at all times until such date as is three years after the Closing Date, (iii) take such other actions as may be necessary to maintain such registrations and qualifications in effect at all times until such date as is three years after the Closing Date and (iv) take all other actions reasonably necessary or advisable to qualify the Registrable Securities for sale by the Investors in such jurisdictions; provided, however, that the Company shall not be required in connection therewith or as a condition thereto (I) to qualify to do business in any jurisdiction where it would not otherwise be required to qualify but for this Section 3(d), (II) to subject itself to general taxation in any such jurisdiction, (III) to file a general consent to service of process in any such jurisdiction, (IV) to provide any undertakings that cause more than nominal expense or burden to the Company or (V) to make any change in its charter or by-laws, which in each case the Board of Directors of the Company determines to be contrary to the best interests of the Company and its stockholders; (e) as promptly as practicable after becoming aware of such event, notify each Investor of the happening of any event of which the Company has knowledge, as a result of which the prospectus included in the Registration Statement, as then in effect, includes an untrue statement of a material fact or omits to state a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, and use its commercially reasonable best efforts promptly to prepare a supplement or amendment to the Registration Statement to correct such untrue statement or omission, and deliver a number of copies of such supplement or amendment to each Investor as such Investor may reasonably request. (f) as promptly as practicable after becoming aware of such event, notify each Investor who holds Registrable Securities -6- being sold of the issuance by the SEC of any stop order or other suspension of effectiveness of the Registration Statement at the earliest possible time; (g) permit a single firm of counsel designated as selling stockholders' counsel by the Investors who hold a majority in interest of the Registrable Securities being sold to review the Registration Statement and all amendments and supplements thereto a reasonable period of time prior to their filing with the SEC; (h) make generally available to its security holders as soon as practical, but not later than ninety (90) days after the close of the period covered thereby, an earnings statement (in form complying with the provisions of Rule 158 under the Securities Act) covering a twelve-month period beginning not later than the first day of the Company's fiscal quarter next following the effective date of the Registration Statement; (i) make available for inspection by any Investor and any attorney, accountant or other agent retained by any such Investor (collectively, the "Inspectors"), all pertinent financial and other records, pertinent corporate documents and properties of the Company (collectively, the "Records"), as shall be reasonably necessary to enable each Inspector to exercise its due diligence responsibility, and cause the Company's officers, directors and employees to supply all information which any Inspector may reasonably request for purposes of such due diligence; provided, however, that each Inspector shall hold in confidence and shall not make any disclosure (except to an Investor) of any Record or other information which the Company determines in good faith to be confidential, and of which determination the Inspectors are so notified, unless (i) the release of such Records is ordered pursuant to a subpoena or other order from a court or government body of competent jurisdiction or (ii) the information in such Records has been made generally available to the public other than by disclosure in violation of this or any other agreement. The Company shall not be required to disclose any confidential information in such Records to any Inspector until and unless such Inspector shall have entered into confidentiality agreements (in form and substance satisfactory to the Company) with the Company with respect thereto, substantially in the form of this Section 3(i). Each Investor agrees that it shall, upon learning that disclosure of such Records is sought in or by a court or governmental body of competent jurisdiction or through other means, give prompt notice to the Company and allow the Company, at its expense, to undertake appropriate action to prevent disclosure of, or to obtain a protective order for, the Records deemed confidential. The Company shall hold in confidence and shall not -7- make any disclosure of information concerning an Investor provided to the Company pursuant to this Agreement unless (i) disclosure of such information is necessary to comply with federal or state securities laws, (ii) the disclosure of such information is necessary to avoid or correct a misstatement or omission in any Registration Statement, (iii) the release of such information is ordered pursuant to a subpoena or other order from a court or governmental body of competent jurisdiction or (iv) such information has been made generally available to the public other than by disclosure in violation of this or any other agreement. The Company agrees that it shall, upon learning that disclosure of such information concerning an Investor is sought in or by a court or governmental body of competent jurisdiction or through other means, give prompt notice to such Investor, at its expense, to undertake appropriate action to prevent disclosure of, or to obtain a protective order for, such information; (j) use its commercially reasonable best efforts (i) to cause all the Registrable Securities covered by the Registration Statement to be listed on the Nasdaq National Market or such other principal securities market on which securities of the same class or series issued by the Company are then listed or traded or (ii) if securities of the same class or series as the Registrable Securities are not then listed on the Nasdaq National Market or any such other securities market, to arrange for at least two market makers to register with the National Association of Securities Dealers, Inc. ("NASD") as such with respect to such Registrable Securities; (k) provide a transfer agent and registrar, which may be a single entity, for the Registrable Securities not later than the effective date of the Registration Statement; (l) cooperate with the Investors who hold Registrable Securities being offered to facilitate the timely preparation and delivery of certificates (not bearing any restrictive legends) representing Registrable Securities to be offered pursuant to the Registration Statement and enable such certificates to be in such denominations or amounts as the Investors may reasonably request and registered in such names as the Investors may request; and, within three business days after a Registration Statement which includes Registrable Securities is ordered effective by the SEC, the Company shall deliver, and shall cause legal counsel selected by the Company to deliver, to the transfer agent for the Registrable Securities (with copies to the Investors whose Registrable Securities are included in such Registration Statement) an instruction substantially in the form attached hereto as Exhibit 1 and an opinion of such counsel, if required by the Company's -8- transfer agent, in the form attached hereto as Exhibit 2; and (m) take all other commercially reasonable actions necessary to expedite and facilitate disposition by the Investor of the Registrable Securities pursuant to the Registration Statement. 4. Obligations of the Investors. In connection with the registration of the Registrable Securities, the Investors shall have the following obligations: (a) It shall be a condition precedent to the obligations of the Company to complete the registration pursuant to this Agreement with respect to the Registrable Securities of a particular Investor that such Investor shall furnish to the Company such information regarding itself, the Registrable Securities held by it and the intended method of disposition of the Registrable Securities held by it as shall be reasonably required to effect the registration of such Registrable Securities and shall execute such documents in connection with such registration as the Company may reasonably request. At least ten (10) days prior to the first anticipated filing date of the Registration Statement, the Company shall notify each Investor of the information the Company requires from each such Investor (the "Requested Information") if any of such Investor's Registrable Securities are eligible for inclusion in the Registration Statement. If at least one (1) business day prior to the filing date the Company has not received the Requested Information from an Investor (a "Non-Responsive Investor"), then the Company may file the Registration Statement without including Registrable Securities of such Non-Responsive Investor; (b) Each Investor by such Investor's acceptance of the Registrable Securities agrees to cooperate with the Company as reasonably requested by the Company in connection with the preparation and filing of the Registration Statement hereunder, unless such Investor has notified the Company in writing of such Investor's election to exclude all of such Investor's Registrable Securities from the Registration Statement; and (c) Each Investor agrees that, upon receipt of any notice from the Company of the happening of any event of the kind described in Section 3(e) or 3(f), such Investor will immediately discontinue disposition of Registrable Securities pursuant to the Registration Statement covering such Registrable Securities until such Investor's receipt of the copies of the supplemented or amended prospectus contemplated by Section 3(e) or 3(f) and, if so directed by the Company, such Investor shall deliver to the Company (at the expense of the Company) or destroy (and deliver to the Company a certificate of destruction) all copies in such Investor's -9- possession, of the prospectus covering such Registrable Securities current at the time of receipt of such notice. 5. Expenses of Registration. All reasonable expenses, other than (a) fees and expenses of investment bankers, (b) brokerage commissions and (c) the fees and expenses of counsel for the Investors, incurred in connection with registrations, filings or qualifications pursuant to Section 3, including, without limitation, all registration, listing and qualifications fees, printers and accounting fees and the fees and disbursements of counsel for the Company, shall be borne by the Company. 6. Indemnification. In the event any Registrable Securities are included in a Registration Statement under this Agreement: (a) To the extent permitted by law, the Company will indemnify and hold harmless each Investor who holds such Registrable Securities, the directors, if any, of such Investor, the officers, if any, of such Investor, each person, if any, who controls any Investor within the meaning of the Securities Act or the Exchange Act, any underwriter (as defined in the Securities Act) for the Investors, the directors, if any, of such underwriter and the officers, if any, of such underwriter, and each person, if any, who controls any such underwriter within the meaning of the Securities Act or the Exchange Act (each, an "Indemnified Person"), against any losses, claims, damages, liabilities or expenses (joint or several) incurred (collectively, "Claims") to which any of them may become subject under the Securities Act, the Exchange Act or otherwise, insofar as such Claims (or actions or proceedings, whether commenced or threatened, in respect thereof) arise out of or are based upon any of the following statements, omissions or violations in the Registration Statement, or any post-effective amendment thereof, or any prospectus included therein: (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or any post-effective amendment thereof or the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, (ii) any untrue statement or alleged untrue statement of a material fact contained in any prospectus (as amended or supplemented, if the Company files any amendment thereof or supplement thereto with the SEC) or the omission or alleged omission to state therein any material fact necessary to make the statements made therein, in light of the circumstances under which the statements therein were made, not misleading or (iii) any violation or alleged violation by the Company of the Securities Act, the Exchange Act, any state securities law or any rule or regulation under the Securities Act, -10- the Exchange Act or any state securities law (the matters in the foregoing clauses (i) through (iii) being, collectively, "Violations"). Subject to the restrictions set forth in Section 6(c) with respect to the number of legal counsel, the Company shall reimburse the Investors and each such controlling person, promptly as such expenses are incurred and are due and payable, for any documented and reasonable legal fees or other documented and reasonable expenses incurred by them in connection with investigating or defending any such Claim. Notwithstanding anything to the contrary contained herein, the indemnification agreement contained in this Section 6(a) (I) shall not apply to a Claim arising out of or based upon a Violation which occurs in reliance upon and in conformity with information furnished in writing to the Company by any Indemnified Person or underwriter for such Indemnified Person expressly for use in connection with the preparation of the Registration Statement or any such amendment thereof or supplement thereto, if such prospectus was timely made available by the Company pursuant to Section 3(c) hereof; and (II)shall not apply to amounts paid in settlement of any Claim if such settlement is effected without the prior written consent of the Company, which consent shall not be unreasonably withheld. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of the Indemnified Person and shall survive the transfer of the Registrable Securities by the Investors pursuant to Section 9. (b) In connection with any Registration Statement in which an Investor is participating, each such Investor agrees to indemnify and hold harmless, to the same extent and in the same manner set forth in Section 6(a), the Company, each of its directors, each of its officers who signs the Registration Statement, each person, if any, who controls the Company within the meaning of the Securities Act or the Exchange Act, any underwriter and any other stockholder selling securities pursuant to the Registration Statement or any of its directors or officers or any person who controls such stockholder or underwriter within the meaning of the Securities Act or the Exchange Act (collectively and together with an Indemnified Person, an "Indemnified Party"), against any Claim to which any of them may become subject, under the Securities Act, the Exchange Act or otherwise, insofar as such Claim arises out of or is based upon any Violation, in each case to the extent (and only to the extent) that such Violation occurs in reliance upon and in conformity with written information furnished to the Company by such Investor expressly for use in connection with such Registration Statement; and such Investor will reimburse any legal or other expenses reasonably incurred by them in connection with investigating or defending any such Claim; provided, however, that the indemnity agreement contained in this -11- Section 6(b) shall not apply to amounts paid in settlement of any Claim if such settlement is effected without the prior written consent of such Investor, which consent shall not be unreasonably withheld; provided, further, however, that the Investor shall be liable under this Section 6(b) for only that amount of a Claim as does not exceed the amount of the net proceeds to such Investor as a result of the sale of Registrable Securities pursuant to such Registration Statement. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of such Indemnified Party and shall survive the transfer of the Registrable Securities by the Investors pursuant to Section 9. Notwithstanding anything to the contrary contained herein, the indemnification agreement contained in this Section 6(b) with respect to any preliminary prospectus shall not inure to the benefit of any Indemnified Party if the untrue statement or omission of material fact contained in the preliminary prospectus was corrected on a timely basis in the prospectus, as then amended or supplemented. (c) Promptly after receipt by an Indemnified Person or Indemnified Party under this Section 6 of notice of the commencement of any action (including any governmental action), such Indemnified Person or Indemnified Party shall, if a Claim in respect thereof is to be made against any indemnifying party under this Section 6, deliver to the indemnifying party a written notice of the commencement thereof and the indemnifying party shall have the right to participate in, and, to the extent the indemnifying party so desires, jointly with any other indemnifying party similarly noticed, to assume control of the defense thereof with counsel reasonably satisfactory to the Indemnified Person or the Indemnified Party, as the case may be; provided, however, that an Indemnified Person or Indemnified Party shall have the right to retain its own counsel with the fees and expenses to be paid by the indemnifying party, if, in the reasonable opinion of counsel retained by the indemnifying party, the representation by such counsel of the Indemnified Person or Indemnified Party and the indemnifying party would be inappropriate due to actual or potential differing interests between such Indemnified Person or Indemnified Party and any other party represented by such counsel in such proceeding. The Company shall pay for only one separate legal counsel for the Investors; such legal counsel shall be selected by the Investors holding a majority in interest of the Registrable Securities included in the Registration Statement to which the Claim relates. The failure to deliver written notice to the indemnifying party within a reasonable time of the commencement of any such action shall not relieve such indemnifying party of any liability to the Indemnified Person or Indemnified Party under this Section 6, except to the extent that the indemnifying party is -12- prejudiced in its ability to defend such action. The indemnification required by this Section 6 shall be made by periodic payments of the amount thereof during the course of the investigation or defense, as such expense, loss, damage or liability is incurred and is due and payable. 7. Contribution. To the extent any indemnification by an indemnifying party is prohibited or limited by law, the indemnifying party agrees to make the maximum contribution with respect to any amounts for which it would otherwise be liable under Section 6 to the fullest extent permitted by law; provided, however, that (a) no contribution shall be made under circumstances where the maker would not have been liable for indemnification under the fault standards set forth in Section 6, (b) no seller of Registrable Securities guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any seller of Registrable Securities who was not guilty of such fraudulent misrepresentation and (c) contribution by any seller of Registrable Securities shall be limited in amount to the net amount of proceeds received by such seller from the sale of such Registrable Securities. 8. Reports under Exchange Act. With a view to making available to the Investors the benefits of Rule 144, the Company agrees to: (a) make and keep public information available, as those terms are understood and defined in Rule 144; (b) file with the SEC in a timely manner all reports and other documents required of the Company under the Securities Act and the Exchange Act; and (c) furnish to each Investor so long as such Investor owns Registrable Securities, promptly upon request, (i) a written statement by the Company that it has complied with the reporting requirements of Rule 144, the Securities Act and the Exchange Act, (ii) a copy of the most recent annual or quarterly report of the Company and such other reports and documents so filed by the Company and (iii) such other information as may be reasonably requested to permit the Investors to sell such securities pursuant to Rule 144 without registration. 9. Assignment of the Registration Rights. The rights to have the Company register Registrable Securities pursuant to this Agreement shall be automatically assigned by the Investors to any Permitted Transferee (as defined herein) in connection with the bona fide transfer for value by an Investor of all or any portion -13- of such securities constituting at least 100,000 shares of Common Stock (or such number of Preferred Shares as shall, at the time of transfer, be convertible (without regard to the limitations in the proviso to the second sentence of Section 9(a) or Section 9(d) of the Certificate of Designations) into at least 100,000 shares of Common Stock) (such number to be subject to equitable adjustment for stock splits, stock dividends, combinations, reclassifications, reorganizations and similar events) only if: (a) the Investor agrees in writing with the transferee or assignee to assign such rights, and a copy of such agreement is furnished to the Company within a reasonable time after such assignment, (b) the Company is, within a reasonable time after such transfer or assignment, furnished with written notice of (i) the name and address of such transferee or assignee and (ii) the securities with respect to which such registration rights are being transferred or assigned, (c) immediately following such transfer or assignment the further disposition of such securities by the transferee or assignee is restricted under the Securities Act and applicable state securities laws, and (d) at or before the time the Company received the written notice contemplated by clause (b) of this sentence the transferee or assignee agrees in writing with the Company to be bound by all of the provisions contained herein. Permitted Transferee means a person which (1) is an "accredited investor" (as defined in Regulation D under the Securities Act) and (2) is either (A) any one of five investment funds for which Genesee Advisers serves as the principal adviser or (B) is a person the assignment or transfer to which is consented to by the Company, such consent not to be unreasonably withheld (it being understood that a proposed assignment by the Buyer to a competitor or potential competitor of the Company or a person which the Company determines in good faith is accumulating or is likely to accumulate ownership of shares of Common Stock for hostile or unfriendly purposes may constitute a basis for withholding such consent). 10. Amendment of Registration Rights. Any provision of this Agreement may be amended and the observance thereof may be waived (either generally or in a particular instance and either retroactively or prospectively), only with the written consent of the Company and Investors who hold a majority in interest of the Registrable Securities. Any amendment or waiver effected in accordance with this Section 10 shall be binding upon each Investor and the Company. 11. Miscellaneous. (a) A person or entity is deemed to be a holder of Registrable Securities whenever such person or entity owns of record such Registrable Securities. If the Company receives -14- conflicting instructions, notices or elections from two or more persons or entities with respect to the same Registrable Securities, the Company shall act upon the basis of instructions, notice or election received from the registered owner of such Registrable Securities. (b) Notices required or permitted to be given hereunder shall be in writing and shall be deemed to be sufficiently given when personally delivered (by hand, by courier, by telephone line facsimile transmission or other means) or sent by certified mail, return receipt requested, properly addressed and with proper postage pre-paid (i) if to the Company, at 2910 Seventh Street, Berkeley, California 94710, Attention: Vice President, General Counsel and Secretary, (ii) if to the Initial Investor, at the address set forth under its name in the Subscription Agreement and (iii) if to any other Investor, at such address as such Investor shall have provided in writing to the Company, or at such other address as each such party furnishes by notice given in accordance with this Section 11(b), and shall be effective, when personally delivered, upon receipt and, when so sent by certified mail, four days after deposit with the United States Postal Service. (c) 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. (d) This Agreement shall be enforced, governed by and construed in accordance with the laws of the State of California applicable to agreements made and to be performed entirely within such State. In the event that any provision of this Agreement is invalid or unenforceable under any applicable statute or rule of law, then such provision shall be deemed inoperative to the extent that it may conflict therewith and shall be deemed modified to conform with such statute or rule of law. Any provision hereof which may prove invalid or unenforceable under any law shall not affect the validity or enforceability of any other provision hereof. (e) This Agreement constitutes the entire agreement among the parties hereto with respect to the subject matter hereof. There are no restrictions, promises, warranties or undertakings, other than those set forth or referred to herein. This Agreement supersedes all prior agreements and understandings among the parties hereto with respect to the subject matter hereof. (f) Subject to the requirements of Section 9 hereof, this Agreement shall inure to the benefit of and be binding upon the successors and assigns of each of the parties hereto. -15- (g) All pronouns and any variations thereof refer to the masculine, feminine or neuter, singular or plural, as the context may require. (h) The headings in this Agreement are for convenience of reference only and shall not limit or otherwise affect the meaning hereof. (i) The Company acknowledges that any failure by the Company to perform its obligations under this Agreement, including, without limitation, the Company's obligations under Section 3(l), or any delay in such performance could result in direct damages to the Investors and the Company agrees that, in addition to any other liability the Company may have by reason of any such failure or delay, the Company shall be liable for all direct and consequential damages caused by any such failure or delay. (j) This Agreement may be executed in two or more counterparts, each of which shall be deemed an original but all of which shall constitute one and the same agreement. This Agreement, once executed by a party, may be delivered to the other party hereto by telephone line facsimile transmission of a copy of this Agreement bearing the signature of the party so delivering this Agreement. -16- IN WITNESS WHEREOF, the parties have caused this Agreement to be duly executed by their respective officers thereunto duly authorized as of day and year first above written. XOMA CORPORATION By __________________________________ John L. Castello Chairman of the Board President and Chief Executive Officer INITIAL INVESTOR: NAME: GENESEE FUND LIMITED-- PORTFOLIO B By__________________________ Name: Title: EXHIBIT 1 to Registration Rights Agreement [Company Letterhead] [Date] [Name and address of Transfer Agent] Ladies and Gentlemen: This letter shall serve as our irrevocable authorization and direction to you (1) to issue shares and the related Preferred Stock Purchase Rights (the "Conversion Shares") of Common Stock, $.0005 par value (the "Common Stock"), of XOMA Corporation, a Delaware corporation (the "Company"), to or upon the order of the registered holders from time to time upon conversion of shares of Non-Voting Cumulative Convertible Preferred Stock, Series D, $.05 par value (the "Preferred Stock"), issued by the Company in such amounts as specified by the Company from time to time and (2) to transfer or re-register the certificates for the shares of Common Stock represented by certificate numbers _______ and _______ for an aggregate of _______ shares (the "Outstanding Shares") of Common Stock presently registered in the name of [Name of Investor] and heretofore issued on conversion of shares of Preferred Stock upon surrender of such certificates to you, notwithstanding the legend appearing on such certificates. Certificates for the Conversion Shares should not bear any restrictive legend and should not be subject to any stop-transfer restriction. The transfer or re-registration of the certificates for the Outstanding Shares by you should be made at such time as you are requested to do so by the record holder of the Outstanding Shares. The certificate issued upon such transfer or re-registration should be registered in such name as requested by the holder of record of the certificate surrendered to you and should not bear any legend which would restrict the transfer of the shares represented thereby. In addition, you are hereby directed to remove any stop-transfer instruction relating to the Outstanding Shares. Contemporaneously with the delivery of this letter, the Company is delivering to you an opinion of Christopher J. Margolin, Vice President, General Counsel and Secretary as to registration of the Outstanding Shares and the Conversion Shares under the Securities Act of 1933, as amended. Should you have any questions concerning this matter, please contact me. Very truly yours, XOMA CORPORATION By:______________________________ Name: Title: Enclosures cc: [Name of Investor] EXHIBIT 2 to Registration Rights Agreement [Date] [Name and address of transfer agent] XOMA CORPORATION Shares of Common Stock Ladies and Gentlemen: I am Vice President, General Counsel and Secretary of XOMA Corporation, a Delaware corporation (the "Company"), and I understand that [Name of Investor] (the "Holder") has acquired (1) shares (the "Preferred Shares") of Non-Voting Cumulative Convertible Preferred Stock, Series D, $.05 par value (the "Preferred Stock"), of the Company and (2) an aggregate of _______ ___ shares (the "Shares") of the Company's Common Stock, $.0005 par value (the "Common Stock"), represented by Certificate Nos. ______ ___ and __________ issued upon conversion of shares of Preferred Stock. The Preferred Shares were purchased by the Holder pursuant to a Preferred Stock Subscription Agreement, dated as of __________, 1996, between the Holder and the Company. Pursuant to a Registration Rights Agreement, dated as of ___________, 1996, between the Company and the Holder (the "Registration Rights Agreement") entered into in connection with the purchase by the Holder of the Preferred Shares, the Company agreed with the Holder, among other things, to register the Shares and shares of Common Stock issuable upon the conversion of the shares of Preferred Stock (the "Conversion Shares") under the Securities Act of 1933, as amended (the "Securities Act"), upon the terms provided in the Registration Rights Agreement. Pursuant to the Registration Rights Agreement, on __________, the Company filed a Registration Statement on Form S-__ (File No. 333-__________) (the "Registration Statement") with the Securities and Exchange Commission (the "SEC") relating to the Shares and the Conversion Shares, which names the Holder as a selling stockholder thereunder. [Other introductory and scope of examination language to be inserted] Based on the foregoing, I am of the opinion that the Shares and the Conversion Shares have been registered under the Securities Act. [Other appropriate language to be included.] Very truly yours, Christopher J. Margolin, Esq. Vice President, General Counsel and Secretary cc: [Name of Investor]