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Exhibit 1.1

        Huntsman Corporation
Shares(1)
Common Stock
($0.01 par value)
Underwriting Agreement

New York, New York
                        , 2005

Citigroup Global Markets Inc.
Credit Suisse First Boston LLC
Deutsche Bank Securities Inc.
Merrill Lynch, Pierce, Fenner & Smith Incorporated
as Representatives of the several Underwriters,
c/o Citigroup Global Markets Inc.
388 Greenwich Street
New York, New York 10013

Ladies and Gentlemen:

        Huntsman Corporation, a corporation organized under the laws of Delaware (the "Company"), proposes to sell to the several underwriters named in Schedule I hereto (the "Underwriters"), for whom you (the "Representatives") are acting as representatives,    shares of Common Stock, $0.01 par value ("Common Stock") of the Company and HMP Investments Trust, a trust organized under the laws of Delaware (the "Selling Stockholder") propose to sell to the several Underwriters            shares of Common Stock (said shares to be issued and sold by the Company and shares to be sold by the Selling Stockholder collectively being hereinafter called the "Underwritten Securities"). The Company and the Selling Stockholder also propose to grant to the Underwriters an option to purchase up to            and            , respectively, additional shares of Common Stock to cover over-allotments (the "Option Securities"; the Option Securities, together with the Underwritten Securities, being hereinafter called the "Securities"). To the extent there are no additional Underwriters listed on Schedule I other than you, the term Representatives as used herein shall mean you, as Underwriters, and the terms Representatives and Underwriters shall mean either the singular or plural as the context requires. The use of the neuter in this Agreement shall include the feminine and masculine wherever appropriate. Certain terms used herein are defined in Section 17 hereof.

        The Company also proposes offer concurrently with the offering of the Securities, pursuant to a separate underwriting agreement to be entered into by the Company and the Underwriters, 5,000,000 shares of mandatory convertible preferred stock, par value $.01 per share ("Preferred Stock") and to grant to the Underwriters an option to purchase up to 750,000 additional shares of Preferred Stock to cover over-allotments.

        Prior to the completion of this offering and the concurrent offering of Preferred Stock, the Company and the Selling Stockholder will complete a series of reorganization transactions (the "Reorganization Transactions"). The Reorganization Transactions will include the following transactions: (a) a wholly owned subsidiary of the Company will merge with and into Huntsman Holdings Preferred Member, LLC (HH Preferred Member"), whereby the former members of HH


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Plus an option to purchase from the Company and the Selling Stockholder up to additional Securities to cover the allotments.

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Preferred Member will receive Common Stock in exchange for their membership interests of HH Preferred Member; (b) a wholly owned subsidiary of the Company will merge with and into Huntsman Holdings LLC ("Huntsman Holdings"), whereby the former members of Huntsman Holdings, other than HH Preferred Member, will receive Common Stock in exchange for their membership interests of Huntsman Holdings; and (c) MatlinPatterson Global Opportunities Partners, L.P., MatlinPatterson Global Opportunities Partners (Bermuda) L.P., MatlinPatterson Global Opportunities Partners B, L.P. and Huntsman Family Holdings Company LLC will cause the contribution of any Common Stock received by either entity as a result of (a) and/or (b), above, to the Selling Stockholder. A list of agreements pursuant to which the Reorganization Transactions will be completed is set forth on Schedule II hereto (collectively, the "Reorganization Agreements").

        The Company and the Underwriters agree that up to            shares [5%] of the Securities (the "Reserved Securities") to be purchased by Merrill Lynch, Pierce, Fenner & Smith Incorporated ("Merrill Lynch") shall be reserved for sale by Merrill Lynch, to certain eligible employees and persons having business relationships with the Company (the "Invitees"), as part of the distribution of the Securities by the Underwriters, subject to the terms of this Agreement, the applicable rules, regulations and interpretations of the National Association of Securities Dealers, Inc. and all other applicable laws, rules and regulations. To the extent that such Reserved Securities are not orally confirmed for purchase by Invitees by the end of the first business day after the date of this Agreement, such Reserved Securities may be offered to the public as part of the public offering contemplated hereby.

        1.    Representations and Warranties.    

        (i)    The Company represents and warrants to, and agrees with, each Underwriter as set forth below in this Section 1.

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        (y)   The Company has not taken, directly or indirectly, any action designed to or that would constitute or that might reasonably be expected to cause or result in, under the Exchange Act or otherwise, stabilization or manipulation of the price of any security of the Company to facilitate the offer, sale or resale of the Securities contemplated by this Agreement.

        (z)   Except as set forth in the Prospectus, or as would not, singularly or in the aggregate, have a Material Adverse Effect, or otherwise require disclosure in the Registration Statement, (i) none of the Company, Huntsman Holdings or any subsidiary is or has been in violation of any Environmental Laws (as defined below), including any Permits required under Environmental Laws; (ii) the Company is not aware of any circumstances, either past, present or that are reasonably foreseeable, that could reasonably be expected to lead to any such violation in the future; (iii) none of the Company, Huntsman Holdings or any subsidiary has received any written notice or other verifiable form of communication, whether from a governmental authority or otherwise, alleging any such violation; (iv) there is no pending or threatened claim, action, investigation or proceeding by any person or entity alleging potential liability of the Company, Huntsman Holdings or any subsidiary (or against any person or entity for whose acts or omissions the Company, Huntsman Holdings or any subsidiary is or may reasonably be expected to be liable, either contractually or by operation of law) for investigatory, cleanup, or other response costs, or natural resource or property damages, or personal injuries, attorney's fees or penalties relating to (A) the presence, or release into the environment, of any Materials of Environmental Concern (as defined below) at any location, or (B) circumstances forming the basis of any violation or potential violation, of any Environmental Law (collectively, "Environmental Claims"); and (v) the Company is not aware of any past or present actions, activities, circumstances, conditions, events or incidents that could reasonably be expected to form the basis of any Environmental Claim. For purposes of this Agreement, "Environmental Laws" means all applicable federal, state, local or foreign laws and regulations relating to pollution or protection of human health or the environment, including, without limitation, laws and regulations relating to emissions, discharges, releases or threatened releases of Materials of Environmental Concern or otherwise relating to the protection of human health and safety, or the use, treatment, storage, disposal, transport or handling of Materials of Environmental Concern; and "Materials of Environmental Concern" means any regulated toxic or hazardous substances, materials or wastes, or petroleum and petroleum products, or other substances that may have an adverse effect on human health or the environment.

        (aa) In the ordinary course of business, the Huntsman Holdings periodically review the effect of Environmental Laws on the business, operations and properties of the Huntsman Holdings and the subsidiaries, in the course of which, or as a result of which, the Huntsman Holdings has identified and evaluated associated costs and liabilities (including, without limitation, any capital or operating expenditures required for cleanup, closure of properties or compliance with Environmental Laws or any permit, license or approval, any related constraints on operating activities, and any potential liabilities to third parties). On the basis of such reviews, investigations and inquiries, the Company has reasonably concluded that, except as disclosed in the Prospectus, any costs and liabilities associated with such matters would not have a Material Adverse Effect, or otherwise require disclosure in the Registration Statement.

        (bb) Neither the Company, Huntsman Holdings nor any subsidiary has incurred any liability for any prohibited transaction (as defined in Section 406 of the Employee Retirement Income Security Act of 1974, as amended ("ERISA")) or any complete or partial withdrawal liability or other liability under Title IV of ERISA with respect to any pension, profit sharing or other plan which is subject to ERISA, to which the Company, Huntsman Holdings or any subsidiary makes or within the preceding six years from the date hereof has made a contribution or had an obligation to make a contribution which liability would, singularly or in the aggregate, reasonably be expected to have a Material Adverse Effect. With respect to such plans, the Company, Huntsman Holdings and the subsidiaries are in compliance in all material respects with all applicable provisions of ERISA, except such noncompliance

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which would not, singularly or in the aggregate, have a Material Adverse Effect. The minimum funding standard under Section 302 of the Employee Retirement Income Security Act of 1974, as amended, and the regulations and published interpretations thereunder ("ERISA"), has been satisfied by each "pension plan" (as defined in Section 3(2) of ERISA) which has been established or maintained by the Company, Huntsman Holdings and/or one or more of its subsidiaries.

        (cc) Neither the Company, Huntsman Holdings or any subsidiary nor any of their respective directors, managers, or partners, as applicable, or officers, in their capacities as such, is in material breach or violation of any provision of the Sarbanes Oxley Act of 2002 and the rules and regulations promulgated in connection therewith (the "Sarbanes Oxley Act"), including Section 402 related to loans and Sections 302 and 906 related to certifications.

        (dd) Except as would not, singularly or in the aggregate, have a Material Adverse Effect, (i) neither the Company, Huntsman Holdings nor any subsidiary nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company, Huntsman Holdings or any subsidiary, is aware of or has taken any action, directly or indirectly, that would result in a violation by such Persons of the FCPA, including, without limitation, making use of the mails or any means or instrumentality of interstate commerce corruptly in furtherance of an offer, payment, promise to pay or authorization of the payment of any money, or other property, gift, promise to give, or authorization of the giving of anything of value to any "foreign official" (as such term is defined in the FCPA) or any foreign political party or official thereof or any candidate for foreign political office, in contravention of the FCPA and (ii) the Company, Huntsman Holdings, the subsidiaries and, to the knowledge of the Company, Huntsman Holdings and its affiliates have conducted their businesses in compliance with the FCPA and have instituted and maintain policies and procedures designed to ensure, and which are reasonably expected to continue to ensure, continued compliance therewith.

        "FCPA" means Foreign Corrupt Practices Act of 1977, as amended, and the rules and regulations thereunder.

        (ee) The operations of the Company, Huntsman Holdings and the subsidiaries are and have been conducted at all times in compliance with applicable financial record keeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the "Money Laundering Laws") and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company, Huntsman Holdings or any subsidiary with respect to the Money Laundering Laws is pending or, to the best knowledge of the Company, threatened, except as would not, singularly or in the aggregate, have a Material Adverse Effect.

        (ff)  Neither the Company, Huntsman Holdings nor any subsidiary nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company, Huntsman Holdings or any subsidiary is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department ("OFAC"); and the Company will not directly or indirectly use the proceeds of the offering, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC, except as would not, singularly or in the aggregate, have a Material Adverse Effect.

        (gg) The Company, Huntsman Holdings and the subsidiaries own, possess, license or have other rights to use all patents, patent applications, trade and service marks, trade and service mark registrations, trade names, copyrights, licenses, inventions, trade secrets, technology, know-how and other intellectual property (collectively, the "Intellectual Property") necessary for the conduct of the Company's and its subsidiaries' businesses as now conducted or as proposed in the Prospectus to be

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conducted upon consummation of the Reorganization Transactions, except where failure to own, possess, license or have other rights to use such Intellectual Property would not have a Material Adverse Effect. Except as set forth in the Prospectus under the caption "Business—Intellectual Property Rights,": (a) to the Company's best knowledge, there is no material infringement or other violation by third parties of any such Intellectual Property owned by the Company or any of its subsidiaries, and there is no pending or threatened action, suit, proceeding or claim by the Company or any of its subsidiaries asserting any such infringement or violation by others; and (b) there is no pending, or to the Company's best knowledge, threatened action, suit, proceeding or claim by others (i) challenging the validity or scope of any such Intellectual Property owned by the Company or any of its subsidiaries, or to the Company's best knowledge, any other such Intellectual Property, or the Company's or its subsidiaries' rights in, any such Intellectual Property or (ii) asserting that the Company or any of its subsidiaries is infringing or otherwise violating the Intellectual Property of any third party, and the Company and its subsidiaries are unaware of any facts which would form a reasonable basis for any of the foregoing, where, if such action, suit, proceeding or claim of infringement or violation were sustained would, singularly or in the aggregate, have a Material Adverse Effect.

        (hh) Except as disclosed in the Registration Statement and the Prospectus, the Company (i) does not, and upon consummation of the Reorganization Transactions will not have any material lending or other relationship with any bank or lending affiliate of any of the Representatives and (ii) does not intend to use any of the proceeds from the sale of the Securities hereunder to repay any outstanding debt owed to any affiliate of any of the Representatives except repayments of indebtedness that are reflected in the Registration Statement.

        Furthermore, the Company represents and warrants to the Underwriters that (i) the Registration Statement, the Prospectus and any preliminary prospectus comply, and any further amendments or supplements thereto will comply, with any applicable laws or regulations of foreign jurisdictions in which the Prospectus or any preliminary prospectus, as amended or supplemented, if applicable, are distributed in connection with the offer and sale of the Reserved Securities which are designated by the Company for sale to the Invitees, and that (ii) no filing with, or authorization, approval, consent, license, order, registration, qualification or decree of any government, governmental instrumentality or court, other than such as have already been obtained, is necessary or required for the performance by the Company of its obligation hereunder under the securities laws and regulations of foreign jurisdictions in which the Reserved Securities are offered outside the United States. The Company has not offered, or caused the Underwriters to offer, Securities to any Invitee with the specific intent to unlawfully influence (i) a customer or supplier of the Company to alter the customer's or supplier's level or type of business with the Company, or (ii) a trade journalist or publication to write or publish favorable information about the Company or its products.

        Any certificate signed by any officer of the Company and delivered to the Representatives or counsel for the Underwriters pursuant to this Agreement on the Closing Date or any settlement date for the Option Securities shall be deemed a representation and warranty by the Company, as to matters covered thereby, to each Underwriter.

        (ii)   The Selling Stockholder represents and warrants to, and agrees with, each Underwriter that:

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        Any certificate signed by any officer of the Selling Stockholder and delivered to the Representatives or counsel for the Underwriters pursuant to this Agreement on the Closing Date or any settlement date for the Option Securities shall be deemed a representation and warranty by the Selling Stockholder, as to matters covered thereby, to each Underwriter.

        2.    Purchase and Sale.    (a) Subject to the terms and conditions and in reliance upon the representations and warranties herein set forth, the Company and the Selling Stockholder agree, severally and not jointly, to sell to each Underwriter, and each Underwriter agrees, severally and not jointly, to purchase from the Company and the Selling Stockholder, at a purchase price of $                                           per share, the amount of the Underwritten Securities set forth opposite such Underwriter's name in Schedule I hereto.

        3.    Delivery and Payment.    Delivery of and payment for the Underwritten Securities and the Option Securities (if the option provided for in Section 2(b) hereof shall have been exercised on or before the third Business Day prior to the Closing Date) shall be made at 10:00 AM, New York City time, on February       , 2005, or at such time on such later date not more than three Business Days

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after the foregoing date as the Representatives shall designate, which date and time may be postponed by agreement among the Representatives, the Company and the Selling Stockholder or as provided in Section 9 hereof (such date and time of delivery and payment for the Securities being herein called the "Closing Date") at the offices of Skadden, Arps, Slate, Meagher & Flom, LLP, Four Times Square, New York, New York 10036. Delivery of the Securities shall be made to the Representatives for the respective accounts of the several Underwriters against payment by the several Underwriters through the Representatives of the respective aggregate purchase prices of the Securities being sold by the Company and each of the Selling Stockholder to or upon the order of the Company and the Selling Stockholder by wire transfer payable in same-day funds to the accounts specified by the Company and the Selling Stockholder. Delivery of the Underwritten Securities and the Option Securities shall be made through the facilities of The Depository Trust Company unless the Representatives shall otherwise instruct.

        The Selling Stockholder will pay all applicable state transfer taxes, if any, involved in the transfer to the several Underwriters of the Securities to be purchased by them from the Selling Stockholder and the respective Underwriters will pay any additional stock transfer taxes involved in further transfers.

        If the option provided for in Section 2(b) hereof is exercised after the third Business Day prior to the Closing Date, the Company and the Selling Stockholder will deliver the Option Securities (at the expense of the Company) to the Representatives, at 10:00 AM, New York City time, on the date specified by the Representatives (which shall be within three Business Days after exercise of said option) for the respective accounts of the several Underwriters, against payment by the several Underwriters through the Representatives of the purchase price thereof to or upon the order of the Company and the Selling Stockholder by wire transfer payable in same-day funds to the accounts specified by the Company and the Selling Stockholder. If settlement for the Option Securities occurs after the Closing Date, the Company and the Selling Stockholder will deliver to the Representatives on the settlement date for the Option Securities, and the obligation of the Underwriters to purchase the Option Securities shall be conditioned upon receipt of, supplemental opinions, certificates and letters confirming as of such date the opinions, certificates and letters delivered on the Closing Date pursuant to Section 6 hereof.

        4.    Offering by Underwriters.    It is understood that the several Underwriters propose to offer the Securities for sale to the public as set forth in the Prospectus.

        5.    Agreements.    

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        (ii)   The Selling Stockholder agrees with the several Underwriters that:

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        6.    Conditions to the Obligations of the Underwriters.    The obligations of the Underwriters to purchase the Underwritten Securities and the Option Securities, as the case may be, shall be subject to the accuracy of the representations and warranties on the part of the Company and the Selling Stockholder contained herein as of the Execution Time, the Closing Date and any settlement date pursuant to Section 3 hereof, to the accuracy of the statements of the Company and the Selling Stockholder made in any certificates pursuant to the provisions hereof, to the performance by the Company and the Selling Stockholder of their respective obligations hereunder and to the following additional conditions:

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        If any of the conditions specified in this Section 6 shall not have been fulfilled when and as provided in this Agreement, or if any of the opinions and certificates mentioned above or elsewhere in this Agreement shall not be reasonably satisfactory in form and substance to the Representatives and counsel for the Underwriters, this Agreement and all obligations of the Underwriters hereunder may be canceled at, or at any time prior to, the Closing Date by the Representatives. Notice of such cancellation shall be given to the Company and the Selling Stockholder in writing or by telephone or facsimile confirmed in writing.

        The documents required to be delivered by this Section 6 shall be delivered at the office of Skadden, Arps, Slate, Meagher & Flom LLP, counsel for the Underwriters, at Four Times Square, New York, New York, 10036, on the Closing Date.

        7.    Reimbursement of Underwriters' Expenses.    If the sale of the Securities provided for herein is not consummated because any condition to the obligations of the Underwriters set forth in Section 6 hereof is not satisfied, because of any termination pursuant to Section 10 hereof or because of any refusal, inability or failure on the part of the Company or the Selling Stockholder to perform any agreement herein or comply with any provision hereof other than by reason of a default by any of the Underwriters, the Company will reimburse the Underwriters severally through Citigroup Global Markets Inc. on demand for all out-of-pocket expenses (including reasonable fees and disbursements of counsel) that shall have been incurred by them in connection with the proposed purchase and sale of the Securities. If the Company is required to make any payments to the Underwriters under this Section 7 because of the Selling Stockholder's refusal, inability or failure to satisfy any condition to the obligations of the Underwriters set forth in Section 6, the Selling Stockholder shall reimburse the Company on demand for all amounts so paid.

        8.    Indemnification and Contribution.    (a) The Company agrees to indemnify and hold harmless each Underwriter, the directors, officers, employees and agents of each Underwriter and each person who controls any Underwriter within the meaning of either the Act or the Exchange Act against any

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and all losses, claims, damages or liabilities, joint or several, to which they or any of them may become subject under the Act, the Exchange Act or other Federal or state statutory law or regulation, at common law or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of a material fact contained in the registration statement for the registration of the Securities as originally filed or in any amendment thereof, or in any Preliminary Prospectus or the Prospectus, or in any amendment thereof or supplement thereto, or arise out of or are based upon 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, and agrees to reimburse each such indemnified party, as incurred, for any legal or other expenses reasonably incurred by them in connection with investigating or defending any such loss, claim, damage, liability or action; provided, however, that the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon any such untrue statement or alleged untrue statement or omission or alleged omission made therein in reliance upon and in conformity with written information furnished to the Company by or on behalf of any Underwriter through the Representatives specifically for inclusion therein. This indemnity agreement will be in addition to any liability which the Company may otherwise have.

        (b)   The Selling Stockholder agrees to indemnify and hold harmless each Underwriter, the directors, officers, employees and agents of each Underwriter and each person who controls any Underwriter within the meaning of either the Act or the Exchange Act to the same extent as the indemnity to each Underwriter contained in subsection (a) above, but only with respect to written information relating to the Selling Stockholder furnished to the Company by or on behalf of the Selling Stockholder specifically for inclusion in the documents referred to in the foregoing indemnity. This indemnity agreement will be in addition to any liability which the Selling Stockholder may otherwise have.

        (c)   Each Underwriter severally and not jointly agrees to indemnify and hold harmless the Company, each of its directors, each of its officers who signs the Registration Statement, and each person who controls the Company within the meaning of either the Act or the Exchange Act and the Selling Stockholder, and each person, if any, who controls the Selling Stockholder within the meaning of the Act or the Exchange Act to the same extent as the indemnity to each Underwriter contained in subsection (a) above, but only with reference to written information relating to such Underwriter furnished to the Company by or on behalf of such Underwriter through the Representatives specifically for inclusion in the documents referred to in the foregoing indemnity. This indemnity agreement will be in addition to any liability which any Underwriter may otherwise have. The Company and the Selling Stockholder acknowledge that the statements set forth in the last paragraph of the cover page regarding delivery of the Securities and, under the heading "Underwriting", (i) the list of Underwriters and their respective participation in the sale of the Securities, (ii) the third paragraph, (iii) the eighth paragraph, (iv) the eleventh paragraph and (v) the twelfth paragraph in any Preliminary Prospectus and the Prospectus constitute the only information furnished in writing by or on behalf of the several Underwriters for inclusion in any Preliminary Prospectus or the Prospectus.

        (d)   In connection with the offer and sale of the Reserved Securities, the Company agrees, to indemnify and hold harmless the Underwriters, their Affiliates and selling agents and each person, if any, who controls any Underwriter within the meaning of either Section 15 of the Act or Section 20 of the Exchange Act, from and against any and all loss, liability, claim, damage and expense (including, without limitation, any legal or other expenses reasonably incurred in connection with defending, investigating or settling any such action or claim), as incurred, (i) arising out of the violation of any applicable laws or regulations of any jurisdiction where Reserved Securities have been offered; (ii) arising out of any untrue statement or alleged untrue statement of a material fact contained in any prospectus wrapper or other material prepared by or with the consent of the Company for distribution to Invitees in connection with the offer and sale of the Reserved Securities or caused by any omission

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or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, when considered in conjunction with any Preliminary Prospectus or the Prospectus not misleading; (iii) caused by the failure of any Invitee to pay for and accept delivery of Reserved Securities which have been orally confirmed for purchase by any Invitee by the end of the first business day after the date of the Agreement; or (iv) related to, arising out of or in connection with, the offer and sale of the Reserved Securities.

        (e)   Promptly after receipt by an indemnified party under this Section 8 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against the indemnifying party under this Section 8, notify the indemnifying party in writing of the commencement thereof; but the failure so to notify the indemnifying party (i) will not relieve it from liability under paragraph (a), (b) or (c) above unless and to the extent it did not otherwise learn of such action and such failure results in the forfeiture by the indemnifying party of substantial rights and defenses and (ii) will not, in any event, relieve the indemnifying party from any obligations to any indemnified party other than the indemnification obligation provided in paragraph (a), (b), (c) or (d) above. The indemnifying party shall be entitled to appoint counsel of the indemnifying party's choice at the indemnifying party's expense to represent the indemnified party in any action for which indemnification is sought (in which case the indemnifying party shall not thereafter be responsible for the fees and expenses of any separate counsel retained by the indemnified party or parties except as set forth below); provided, however, that such counsel shall be reasonably satisfactory to the indemnified party. Notwithstanding the indemnifying party's election to appoint counsel to represent the indemnified party in an action, the indemnified party shall have the right to employ separate counsel (including local counsel), and the indemnifying party shall bear the reasonable fees, costs and expenses of such separate counsel if (i) the use of counsel chosen by the indemnifying party to represent the indemnified party would present such counsel with a conflict of interest, (ii) the actual or potential defendants in, or targets of, any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that there may be legal defenses available to it and/or other indemnified parties which are different from or additional to those available to the indemnifying party, (iii) the indemnifying party shall not have employed counsel reasonably satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of the institution of such action or (iv) the indemnifying party shall authorize the indemnified party to employ separate counsel at the expense of the indemnifying party. An indemnifying party will not, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any pending or threatened claim, action, suit or proceeding in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified parties are actual or potential parties to such claim or action) unless such settlement, compromise or consent (i) includes an unconditional release of each indemnified party from all liability arising out of such claim, action, suit or proceeding and (ii) does not include a statement as to, or an admission of, fault, culpability or a failure to act by or on behalf of an indemnified party. Notwithstanding anything contained herein to the contrary, if indemnity may be sought pursuant to Section 8(c) hereof in respect of such action or proceeding, then in addition to such separate firm for the indemnified parties, the indemnifying party shall be liable for the reasonable fees and expenses of not more than one separate firm (in addition to any local counsel) for Merrill Lynch, the directors, officers, employees and agents of Merrill Lynch, and all persons, if any, who control Merrill Lynch within the meaning of either the Act or the Exchange Act for the defense of any losses, claims, damages and liabilities arising in connection with the Reserved Securities which are designated by the Company for sale to Invitees.

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        (f)    In the event that the indemnity provided in paragraph (a), (b) or (c) of this Section 8 is unavailable to or insufficient to hold harmless an indemnified party for any reason, the Company, and the Selling Stockholder and the Underwriters severally agree to contribute to the aggregate losses, claims, damages and liabilities (including legal or other expenses reasonably incurred in connection with investigating or defending same) (collectively "Losses") to which the Company and the Selling Stockholder and one or more of the Underwriters may be subject in such proportion as is appropriate to reflect the relative benefits received by the Company and the Selling Stockholder on the one hand and by the Underwriters on the other from the offering of the Securities; provided, however, that in no case shall any Underwriter (except as may be provided in any agreement among underwriters relating to the offering of the Securities) be responsible for any amount in excess of the underwriting discount or commission applicable to the Securities purchased by such Underwriter hereunder. If the allocation provided by the immediately preceding sentence is unavailable for any reason, the Company and the Selling Stockholder and the Underwriters severally shall contribute in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company and the Selling Stockholder on the one hand and of the Underwriters on the other in connection with the statements or omissions which resulted in such Losses as well as any other relevant equitable considerations. Benefits received by the Company and the Selling Stockholder, shall be deemed to be equal to the total net proceeds from the offering (before deducting expenses) received by the Company on one hand and the Selling Stockholder on the other, and benefits received by the Underwriters shall be deemed to be equal to the total underwriting discounts and commissions, in each case as set forth on the cover page of the Prospectus. Relative fault shall be determined by reference to, among other things, whether any untrue or any alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information provided by the Company and the Selling Stockholder, on the one hand or the Underwriters on the other, the intent of the parties and their relative knowledge, access to information and opportunity to correct or prevent such untrue statement or omission. The Company and the Selling Stockholder and the Underwriters agree that it would not be just and equitable if contribution were determined by pro rata allocation or any other method of allocation which does not take account of the equitable considerations referred to above. Notwithstanding the provisions of this paragraph (d), no person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. For purposes of this Section 8, each person who controls an Underwriter within the meaning of either the Act or the Exchange Act and each director, officer, employee and agent of an Underwriter shall have the same rights to contribution as such Underwriter, and each person who controls the Company within the meaning of either the Act or the Exchange Act, each officer of the Company who shall have signed the Registration Statement and each director of the Company shall have the same rights to contribution as the Company, subject in each case to the applicable terms and conditions of this paragraph (f).

        (g)   The liability of the Selling Stockholder under the Selling Stockholder representations and warranties contained in Section 1 hereof and under the indemnity and contribution agreements contained in this Section 8 and otherwise with respect to this Agreement shall be limited to an amount equal to the initial public offering price of the Securities sold by the Selling Stockholder to the Underwriters. The Company and the Selling Stockholder may agree, as among themselves and without limiting the rights of the Underwriters under this Agreement, as to the respective amounts of such liability for which they each shall be responsible.

        9.    Default by an Underwriter.    If any one or more Underwriters shall fail to purchase and pay for any of the Securities agreed to be purchased by such Underwriter or Underwriters hereunder and such failure to purchase shall constitute a default in the performance of its or their obligations under this Agreement, the remaining Underwriters shall be obligated severally to take up and pay for (in the respective proportions which the amount of Securities set forth opposite their names in Schedule I hereto bears to the aggregate amount of Securities set forth opposite the names of all the remaining

26



Underwriters) the Securities which the defaulting Underwriter or Underwriters agreed but failed to purchase; provided, however, that in the event that the aggregate amount of Securities which the defaulting Underwriter or Underwriters agreed but failed to purchase shall exceed 10% of the aggregate amount of Securities set forth in Schedule I hereto, the remaining Underwriters shall have the right to purchase all, but shall not be under any obligation to purchase any, of the Securities, and if such nondefaulting Underwriters do not purchase all the Securities, this Agreement will terminate without liability to any nondefaulting Underwriter, the Selling Stockholder or the Company. In the event of a default by any Underwriter as set forth in this Section 9, the Closing Date shall be postponed for such period, not exceeding five Business Days, as the Representatives shall determine in order that the required changes in the Registration Statement and the Prospectus or in any other documents or arrangements may be effected. Nothing contained in this Agreement shall relieve any defaulting Underwriter of its liability, if any, to the Company, the Selling Stockholder and any nondefaulting Underwriter for damages occasioned by its default hereunder.

        10.    Termination.    This Agreement shall be subject to termination in the absolute discretion of the Representatives, by notice given to the Company prior to delivery of and payment for the Securities, if at any time prior to such time (i) trading in the Company's Common Stock shall have been suspended by the Commission or the New York Stock Exchange or trading in securities generally on the New York Stock Exchange shall have been suspended or limited or minimum prices shall have been established on such exchange, (ii) a banking moratorium shall have been declared either by Federal or New York State authorities or (iii) there shall have occurred any outbreak or escalation of hostilities, declaration by the United States of a national emergency or war, or other calamity or crisis the effect of which on financial markets is such as to make it, in the sole judgment of the Representatives, impractical or inadvisable to proceed with the offering or delivery of the Securities as contemplated by the Prospectus (exclusive of any supplement thereto).

        11.    Representations and Indemnities to Survive.    The respective agreements, representations, warranties, indemnities and other statements of the Company or its officers, of the Selling Stockholder and of the Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation made by or on behalf of any Underwriter, the Selling Stockholder or the Company or any of the officers, directors, employees, agents or controlling persons referred to in Section 8 hereof, and will survive delivery of and payment for the Securities. The provisions of Sections 7 and 8 hereof shall survive the termination or cancellation of this Agreement.

        12.    Notices.    All communications hereunder will be in writing and effective only on receipt, and, if sent to the Representatives, will be mailed, delivered or telefaxed to Citigroup Global Markets, Inc.; or, if sent to the Company, will be mailed, delivered or telefaxed to (801) 584-5788 and confirmed to it at 500 Huntsman Way, Salt Lake City, Utah 84108, attention of the Legal Department; or if sent to the Selling Stockholder, will be mailed, delivered or telefaxed and confirmed to it at the address set forth in Schedule VI hereto.

        13.    Successors.    This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers, directors, employees, agents and controlling persons referred to in Section 8 hereof, and no other person will have any right or obligation hereunder.

        14.    Applicable Law.    This Agreement will be governed by and construed in accordance with the laws of the State of New York applicable to contracts made and to be performed within the State of New York.

        15.    Counterparts.    This Agreement may be signed in one or more counterparts, each of which shall constitute an original and all of which together shall constitute one and the same agreement.

27



        16.    Headings.    The section headings used herein are for convenience only and shall not affect the construction hereof.

        17.    Definitions.    The terms which follow, when used in this Agreement, shall have the meanings indicated.

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        If the foregoing is in accordance with your understanding of our agreement, please sign and return to us the enclosed duplicate hereof, whereupon this letter and your acceptance shall represent a binding agreement among the Company, the Selling Stockholder and the several Underwriters.

    Very truly yours,

 

 

HUNTSMAN CORPORATION

 

 

By:


Name:
Title:

 

 

HMP INVESTMENTS TRUST

 

 

By:


Name:
Title:

29


The foregoing Agreement is hereby
confirmed and accepted as of the
date first above written.
   

CITIGROUP GLOBAL MARKETS INC.

 

 

By:


Name:
Title:

 

 

CREDIT SUISSE FIRST BOSTON LLC

 

 

By:


Name:
Title:

 

 

DEUTSCHE BANK SECURITIES INC.

 

 

By:


Name:
Title:

 

 

By:


Name:
Title:

 

 

MERRILL LYNCH, PIERCE FENNER & SMITH INCORPORATED

 

 

By:


Name:
Title:

 

 

For themselves and the other
several Underwriters named in
Schedule I to the foregoing
Agreement.

 

 

30


SCHEDULE I

Underwriters

  Number of Underwritten
Securities to be Purchased

Citigroup Global Markets Inc.    
Credit Suisse First Boston LLC    
Deutsche Bank Securities Inc.    
Merrill Lynch, Pierce, Fenner & Smith Incorporated    
J.P. Morgan Securities, Inc.    
Lehman Brothers, Inc.    
UBS Securities LLC    
CIBC World Markets Corp.    
Jeffries & Company, Inc.    
Natexis Bleichroeder Inc.    
WR Hambrecht & Co., LLC    
Scotia Capital (USA) Inc.    
Total    

SCHEDULE II

Reorganization Agreements


SCHEDULE III

Scheduled Subsidiaries

Alta One Inc.
HMP Equity Holdings Corporation
Huntsman Advanced Materials Investment LLC
Huntsman Advanced Materials Holdings LLC
Huntsman Advanced Materials LLC
Huntsman Group Inc.
Huntsman Holdings, LLC
Huntsman Holdings Preferred Member, LLC
Huntsman International Holdings LLC
Huntsman International LLC
Huntsman LLC
Huntsman Specialty Chemicals Holdings Corp.
Huntsman Specialty Chemicals Corp.


SCHEDULE IV

Foreign Qualifications

Entity

  Jurisdiction(s) of Foreign
Qualification

  Status
Huntsman Corporation        
Huntsman Holdings, LLC        
Alta One Inc.        
HMP Equity Holdings Corporation        
Huntsman Advance Materials Holdings LLC        
Huntsman Advanced Materials LLC        
Huntsman Group Inc.        
Huntsman Holdings Preferred Member, LLC        
Huntsman International Holdings LLC        
Huntsman International LLC        
Huntsman LLC        
Huntsman Specialty Chemicals Holdings Corp.        
Huntsman Specialty Chemicals Corp.        

SCHEDULE V

Persons Signing Lock-up Letters

Directors:
Jon Huntsman
Peter Huntsman
David Matlin
Chris Pechock
Rich Michaelson

Executive Officers:
Peter Huntsman
Kimo Esplin
Sam Scruggs
Anthony Hankins
Paul Hulme
Tom Keenan
Kevin Ninow
Don Stanutz
Mike Kern
Brian Ridd
Russ Healy

Other Officers:
John Heskett
Sean Douglas
Kevin Hardman

Stockholders:
HMP Investments Trust
MatlinPatterson Global Opportunities Partners L.P.
MatlinPatterson Global Opportunities Partners (Bermuda) L.P.
MatlinPatterson Global Opportunities Partners B, L.P.
Huntsman Family Holdings Company LLC
Huntsman Holdings Preferred Member, LLC
Consolidated Press (Finance) Limited
David Parkin

Other:
Huntsman Holdings, LLC


SCHEDULE VI

Selling Stockholder:

  Number of Underwritten Securities to be Sold
  Maximum Number of Option Securities to be Sold
HMP Investments Trust
[address, fax no.]
       

 

 

 

 

 
   
 
  Total        
   
 

ANNEX A

Form of Lock-up Agreement

Huntsman Corporation
Public Offering of Common Stock

        February    , 2005

Citigroup Global Markets Inc.
Credit Suisse First Boston LLC
Deutsche Bank Securities Inc.
Merrill Lynch, Pierce, Fenner & Smith Incorporated
as Representatives of the several Underwriters,
c/o Citigroup Global Markets Inc.
388 Greenwich Street
New York, New York 10013

Ladies and Gentlemen:

        This letter is being delivered to you in connection with the proposed Underwriting Agreement (the "Underwriting Agreement"), among Huntsman Corporation, a Delaware corporation (the "Company"), and each of you as representatives of a group of Underwriters named therein, relating to an underwritten public offering (the "IPO") of shares of common stock, $0.01 par value of the Company (the "Common Stock").

        In order to induce you and the other Underwriters to enter into the Underwriting Agreement, the undersigned will not, without the prior written consent of Citigroup Global Markets Inc., offer, sell, contract to sell, pledge, transfer or otherwise dispose of (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition (whether by actual disposition or effective economic disposition due to cash settlement or otherwise) by the undersigned or any controlled affiliate of the undersigned, directly or indirectly, including the filing (or participation in the filing) of a registration statement with the Securities and Exchange Commission in respect of, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Securities and Exchange Commission promulgated thereunder (in each case, a "Disposition") with respect to, any shares of capital stock of or other equity interests in Huntsman Holdings LLC or the Company or, prior to the consummation of the Reorganization Transaction (as described in the Company's registration statement relating to the IPO), the capital stock of or other equity interests in any of their respective subsidiaries whose capital stock or other equity interests may be converted into or exercised or exchanged for capital stock of or other equity in the Company as part of such Reorganization Transaction (collectively "Huntsman Equity Securities"), whether now owned or acquired after the date of this letter, or any securities convertible into, or exercisable or exchangeable for Huntsman Equity Securities or securities issued or issuable upon or with respect to Huntsman Equity Securities by way of stock dividend or stock split or in connection with a combination of shares, recapitalization, merger, consolidation or other reorganization or otherwise (the "Lock-up Securities"), or publicly announce an intention to effect any such transaction, beginning on the date of this letter and ending on the 180th day after the date of the Underwriting Agreement (the "Initial Lock-up Period").

        Nothing contained herein shall be deemed to prohibit the exercise (including cashless exercise) by the undersigned of any warrant, option or right held by the undersigned, it being understood that this letter does apply to any Disposition of such warrant, option or right and any security issuable upon such exercise.



        The foregoing restrictions shall not apply to Dispositions of Lock-up Securities effected pursuant to (a) the Underwriting Agreement or (b) the exceptions listed below (provided that, with respect to clause (b), the conditions described in the following paragraph are met):

        The exceptions described in the foregoing paragraph shall apply only if:

provided that, (x) the conditions described in both (a) and (b) shall not apply to clause (ii) above, (y) the condition described in (a) above shall not apply to clauses (iv), (v) and (vii) above and (z) the condition described in (b) shall not apply to clause (iii) above.

        In addition, in the event that either (x) during the last 17 days of the Initial Lock-up Period referred to above, the Company issues an earnings release or a press release announcing a significant event or (y) prior to the expiration of such Initial Lock-up Period, the Company announces that it will release earnings or issue a press release announcing a significant event during the 17-day period beginning on the last day of such Initial Lock-up Period, the restrictions described above shall continue to apply until the expiration of the 17-day period beginning on the date of the earnings release or the press release, unless Citigroup Global Markets Inc. waives, in writing, such extension.

        You hereby acknowledge and agree that, prior to engaging in any transaction or taking any other action that is subject to the terms of this lock-up agreement during the period from the date of this lock-up agreement to and including the 34th day following the expiration of the Initial Lock-up Period, you will give notice thereof to Paul M. Wilson, the Securities Compliance Officer of the Company, at (801) 584-5776 and will not consummate such transaction or take any such action unless you have received written confirmation from the Company that the Initial Lock-up Period (as may have been extended pursuant to the previous paragraph) has expired.



        If for any reason (i) the Underwriting Agreement is not entered into prior to March 1, 2005 or (ii) if entered into, the Underwriting Agreement shall be terminated prior to the Closing Date (as defined in the Underwriting Agreement), then in either case this lock-up agreement shall terminate automatically.

    Yours very truly,

 

 


Name:
Address:

ANNEX B

Form of Letter from Deloitte & Touche LLC


ANNEX C

Form of CFO/Controller Certificate




QuickLinks

Reorganization Agreements
Foreign Qualifications