Underwriting Agreement

EX-1.1 2 d20941exv1w1.htm UNDERWRITING AGREEMENT exv1w1

EXHIBIT 1.1

Bill Barrett Corporation

Common Stock, par value $.001 per share

Underwriting Agreement

December 9, 2004

Goldman, Sachs & Co.,
J. P. Morgan Securities Inc.,
Lehman Brothers Inc.,
Credit Suisse First Boston LLC,
Morgan Stanley & Co. Incorporated,
Petrie Parkman & Co., Inc.,
First Albany Capital Inc.,
As representatives of the several Underwriters
named in Schedule I hereto,
c/o Goldman, Sachs & Co.,
85 Broad Street,
New York, New York 10004

Ladies and Gentlemen:

Bill Barrett Corporation, a Delaware corporation (the “Company”), proposes, subject to the terms and conditions stated herein, to issue and sell to the Underwriters named in Schedule I hereto (the “Underwriters”) an aggregate of 13,000,000 shares (the “Firm Shares”) and, at the election of the Underwriters, up to 1,950,000 additional shares (the “Optional Shares”) of common stock, par value $.001 per share (“Stock”) of the Company (the Firm Shares and the Optional Shares that the Underwriters elect to purchase pursuant to Section 2 hereof being collectively called the “Shares”).

1. The Company represents and warrants to, and agrees with, each of the Underwriters that:

(a) A registration statement on Form S-1 (File No. 333-114554) (the “Initial Registration Statement”) in respect of the Shares has been filed with the Securities and Exchange Commission (the “Commission”); the Initial Registration Statement and any post-effective amendment thereto, each in the form heretofore delivered to you, and, excluding exhibits thereto, to you for each of the other Underwriters, have been declared effective by the Commission in such form; other than a registration statement, if any, increasing the size of the offering (a “Rule 462(b) Registration Statement”), filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended (the “Act”), which became effective upon filing, no other document with respect to the Initial Registration Statement has heretofore been filed with the Commission; and no stop order suspending the effectiveness of the Initial Registration Statement, any post-effective amendment thereto or the Rule 462(b) Registration Statement, if any, has been issued and no proceeding for that purpose has been initiated or threatened by the Commission (any preliminary prospectus included in the Initial

Registration Statement or filed with the Commission pursuant to Rule 424(a) of the rules and regulations of the Commission under the Act is hereinafter called a “Preliminary Prospectus”; the various parts of the Initial Registration Statement and the Rule 462(b) Registration Statement, if any, including all exhibits thereto and including the information contained in the form of final prospectus filed with the Commission pursuant to Rule 424(b) under the Act in accordance with Section 6(a) hereof and deemed by virtue of Rule 430A under the Act to be part of the Initial Registration Statement at the time it was declared effective, each as amended at the time such part of the Initial Registration Statement became effective or such part of the Rule 462(b) Registration Statement, if any, became or hereafter becomes effective, are hereinafter collectively called the “Registration Statement”; and such final prospectus, in the form first filed pursuant to Rule 424(b) under the Act, is hereinafter called the “Prospectus”);

(b) No order preventing or suspending the use of any Preliminary Prospectus has been issued by the Commission, and each Preliminary Prospectus, at the time of filing thereof, conformed in all material respects to the requirements of the Act and the rules and regulations of the Commission thereunder, and did not contain an 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 the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by an Underwriter through Goldman, Sachs & Co. expressly for use therein;

(c) The Registration Statement conforms, and the Prospectus and any further amendments or supplements to the Registration Statement or the Prospectus will conform, in all material respects to the requirements of the Act and the rules and regulations of the Commission thereunder and do not and will not, as of the applicable effective date as to the Registration Statement and any amendment thereto, and as of the applicable filing date as to the Prospectus and any amendment or supplement thereto, contain an 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 under which they were made in the case of the Prospectus and any amendment or supplement thereto, not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by an Underwriter through Goldman, Sachs & Co. expressly for use therein;

(d) Neither the Company nor any of its subsidiaries has sustained since the date of the latest audited financial statements included in the Prospectus any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Prospectus; and, since the respective dates as of which information is given in the Registration Statement and the Prospectus, there has not been any change in the capital stock of the Company or its subsidiaries (other than issuances of the Company’s stock pursuant to stock options outstanding as of the date of this Agreement under the Company’s stock option plans) or any increase of more than $20 million in the long-term debt of the Company and its subsidiaries taken as a whole, or any material adverse change, or any development involving a prospective material adverse change, in or affecting the general affairs, management, financial position, stockholders’ equity or results of operations of the Company and its subsidiaries taken as a whole, otherwise than as set forth or contemplated in the Prospectus;

(e) The Company and its subsidiaries have legal, valid and defensible title to substantially all of the interests in oil and gas properties underlying the Company’s estimates of its net proved reserves contained in the Prospectus and to substantially all other real and personal property reflected in the Prospectus as assets owned by them, in each case free and clear of all liens, encumbrances and defects except such as are described in the Prospectus or would not have a material adverse effect on the current or future consolidated financial position, stockholders’ equity or results of operations of the Company and its subsidiaries taken as a whole (a “Material Adverse Effect”); and any other real property and buildings held under lease by the Company and its subsidiaries are held by them under valid, subsisting and enforceable leases, with such exceptions as are not material and do not interfere with the use made and proposed to be made of such property and buildings by the Company and its subsidiaries; the working interests derived from oil, gas and mineral leases or mineral interests which constitute a portion of the real property held or leased by the Company or its subsidiaries reflect in all material respects the right of the Company and its subsidiaries to explore, develop or produce hydrocarbons from such real property, and the care taken by the Company and its subsidiaries with respect to acquiring or otherwise procuring such leases or mineral interests was generally consistent with standard industry practices in the areas in which the Company operates for acquiring or procuring leases and interests therein to explore, develop or produce hydrocarbons, except that the net revenue interest arrangement with Wind River Resources Corporation (“WRRC”) as documented in that certain Exploration Agreement between WRRC and the Company dated effective August 12, 2002 and that certain Covenant Not to Sell and Purchase Offer Agreement between WRRC and the Company dated effective August 12, 2002 may not be customary in the industry;

(f) The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware, with corporate power and authority to own its properties and conduct its business as described in the Prospectus, and is duly qualified as a foreign corporation for the transaction of business and is in good standing under the laws of each other jurisdiction in which it owns or leases properties or conducts any business so as to require such qualification, or is subject to no material liability or disability by reason of the failure to be so qualified in any such jurisdiction, except where the failure to be so qualified or to be in good standing in any such jurisdiction would not have a Material Adverse Effect; and each subsidiary of the Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of its jurisdiction of incorporation;

(g) The Company has an authorized capitalization as set forth in the Prospectus, and all of the issued shares of capital stock of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and conform to the description of the Stock contained in the Prospectus; and all of the issued shares of capital stock of each subsidiary of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and (except for directors’ qualifying shares and except as set forth in the Prospectus) are owned directly or indirectly by the Company, free and clear of all liens, encumbrances, equities or claims;

(h) The unissued Shares to be issued and sold by the Company to the Underwriters hereunder have been duly and validly authorized and, when issued and delivered against payment therefor as provided herein, will be duly and validly issued and fully paid and non-assessable and will conform to the description of the Stock contained in the Prospectus;

(i) The issue and sale of the Shares by the Company and the compliance by the Company with all of the provisions of this Agreement and the consummation of the transactions herein contemplated (A) will not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the property or assets of the Company or any of its subsidiaries is subject, (B) will not result in any violation of the provisions of the Certificate of Incorporation or By-laws (in each case, as amended or restated) of the Company, and (C) will not result in any violation of any statute or any order, rule or regulation of any court or governmental agency or body having jurisdiction over the Company or any of its subsidiaries or any of their properties, except with respect to (A) and (C), for such conflicts, breaches, violations or defaults that would not result in a Material Adverse Effect; and no consent, approval, authorization, order, registration or qualification of or with any such court or governmental agency or body is required for the issue and sale of the Shares or the consummation by the Company of the transactions contemplated by this Agreement, except the registration of the Shares under the Act and under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) and such consents, approvals, authorizations, registrations or qualifications as may be required under state securities or Blue Sky laws in connection with the purchase and distribution of the Shares by the Underwriters;

(j) Neither the Company nor any of its subsidiaries is (A) in violation of its Certificate of Incorporation or By-laws (in each case, as amended or restated) or (B) in default in the performance or observance of any material obligation, agreement, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement, lease or other agreement or instrument to which it is a party or by which it or any of its properties may be bound, except in the case of (B), for such violations and defaults that would not result in a Material Adverse Effect;

(k) The statements set forth in the Prospectus under the caption “Description of Capital Stock”, insofar as they purport to constitute a summary of the terms of the Stock and under the caption “Underwriting”, insofar as they purport to describe the provisions of the laws and documents referred to therein, fairly and accurately summarize and describe such matters in all material respects;

(l) Other than as set forth in the Prospectus, there are no legal or governmental proceedings pending to which the Company or any of its subsidiaries is a party or of which any property of the Company or any of its subsidiaries is the subject which, if determined adversely to the Company or any of its subsidiaries, would individually or in the aggregate have a Material Adverse Effect; and, to the best of the Company’s knowledge, no such proceedings are threatened or contemplated by governmental authorities or threatened by others;

(m) The Company is not and, after giving effect to the offering and sale of the Shares, will not be an “investment company”, as such term is defined in the Investment Company Act of 1940, as amended (the “Investment Company Act”);

(n) Deloitte & Touche LLP, who have certified (A) the consolidated financial statements of the Company and its subsidiaries, (B) the statement of revenues and direct operating expenses relating to the Wind River Acquisition Properties acquired from Williams Production RMT Inc., and (C) the statement of revenues and direct operating expenses relating to the Piceance Basin Acquisition Properties acquired from Calpine Corporation and Calpine Natural Gas L.P., are

independent public accountants as required by the Act and the rules and regulations of the Commission thereunder.

(o) KPMG LLP, who have certified the statement of revenues and direct operating expenses relating to the assets acquired from Intoil, Inc., are independent public accountants as required by the Act and the rules and regulations of the Commission thereunder.

(p) This Agreement has been duly authorized, executed and delivered by the Company.

(q) Except as described in the Registration Statement and except as would not, singly or in the aggregate, result in a Material Adverse Effect, (A) none of the Company or any of its subsidiaries is in violation of any federal, state, local or foreign statute, law, rule, regulation, ordinance, code, policy or rule of common law or any judicial or administrative interpretation thereof, including any judicial or administrative order, consent, decree or judgment, relating to pollution or protection of human health, the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including, without limitation, laws and regulations relating to the release or threatened release of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum or petroleum products, asbestos-containing materials or mold (collectively, “Hazardous Materials”) or to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials (collectively, “Environmental Laws”), (B) the Company and its subsidiaries have all permits, authorizations and approvals required under any applicable Environmental Laws and are each in compliance with their requirements, (C) there are no pending or, to the knowledge of the Company, threatened administrative, regulatory or judicial actions, suits, demands, demand letters, claims, liens, notices of noncompliance or violation, investigation or proceedings relating to any Environmental Law against the Company, or any of its subsidiaries, and (D) to the knowledge of the Company, there are no events or circumstances that would reasonably be expected to form the basis of an order for clean-up or remediation, or an action, suit or proceeding by any private party or governmental body or agency, against or affecting the Company or any of its subsidiaries relating to Hazardous Materials or any Environmental Laws.

(r) Other than persons granted registration rights pursuant to the Registration Rights Agreement dated March 28, 2002 among the Company and certain of the holders of its Series B preferred stock (the “2002 Registration Rights Agreement”), and the Registration Rights Agreement dated September 1, 2004 between the Company and Goldman Sachs Credit Partners L.P. (in its capacity as identified therein) (the “2004 Registration Rights Agreement”), there are no persons with registration rights or other similar rights to have any securities registered pursuant to the Registration Statement or otherwise registered by the Company under the Act, and any such rights under the 2002 Registration Rights Agreement or the 2004 Registration Rights Agreement are not applicable to the offering of the Shares or have been effectively waived by the holders thereof, and any such waivers remain in full force and effect.

(s) Ryder Scott Company, L.P., whose reports as of February 2, 2004, July 2, 2004 and September 9, 2004 are referenced in the Prospectus, was, as of the date of such report, and is, as of the date hereof, an independent petroleum engineer with respect to the Company. Netherland, Sewell & Associates, Inc., whose reports as of February 2, 2004 and July 8, 2004 are referenced in the Prospectus, was, as of the dates of such report, and is, as of the date hereof, an independent petroleum engineer with respect to the Company.

(t) The information underlying the estimates of reserves of the Company and its subsidiaries, which was supplied by the Company to Ryder Scott Company, L.P. and Netherland, Sewell & Associates, Inc. for purposes of reviewing the reserve reports and estimates of the Company and preparing the respective letters (the “Reserve Report Letters” and each a “Reserve Report Letter”) of each of Ryder Scott Company, L.P. and Netherland, Sewell & Associates, Inc. included as annexes to the Prospectus, including, without limitation, production, costs of operation and development, current prices for production, agreements relating to current and future operations and sales of production, was true and correct in all material respects on the dates such estimates were made and such information was supplied and was prepared in accordance with customary industry practices; other than normal production of the reserves and intervening market commodity price fluctuations described in the Prospectus, the Company is not aware of any facts or circumstances that would result in a material adverse change in the reserves, or the present value of future net cash flows therefrom, as described in the Prospectus and as reflected in each Reserve Report Letter; estimates of such reserves and present values as described in the Prospectus and reflected in each Reserve Report Letter comply in all material respects with the applicable requirements of Regulation S-X and Industry Guide 2 under the Act.

(u) The Company and each of its subsidiaries maintain a system of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations, (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability, (iii) access to assets is permitted only in accordance with management’s general or specific authorization and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences.

(v) The unaudited pro forma balance sheet and the unaudited pro forma statement of operations, the related notes thereto and the related pro forma supplementary information set forth in the Registration Statement and the Prospectus have been prepared in all material respects in accordance with the applicable requirements of Rule 11-02 of Regulation S-X promulgated by the Commission, have been compiled on the pro forma basis described therein and, in the opinion of the Company, the assumptions used in the preparation thereof were reasonable at the time made and the adjustments used therein are based upon good faith estimates and assumptions believed by the Company to be reasonable at the time made.

2. Subject to the terms and conditions herein set forth, (a) the Company agrees to issue and sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at a purchase price per share of $23.375, the number of Firm Shares set forth opposite the name of such Underwriter in Schedule I hereto and (b) in the event and to the extent that the Underwriters shall exercise the election to purchase Optional Shares as provided below, the Company agrees to issue and sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at the purchase price per share set forth in clause (a) of this Section 2, that portion of the number of Optional Shares as to which such election shall have been exercised (to be adjusted by you so as to eliminate fractional shares) determined by multiplying such number of Optional Shares by a fraction, the numerator of which is the maximum number of Optional Shares which such Underwriter is entitled to purchase as set forth opposite the name of such Underwriter in Schedule I hereto and the denominator of which is

the maximum number of Optional Shares that all of the Underwriters are entitled to purchase hereunder.

The Company hereby grants to the Underwriters the right to purchase at their election up to 1,950,000 Optional Shares, at the purchase price per share set forth in the paragraph above, for the sole purpose of covering sales of shares in excess of the number of Firm Shares, provided that the purchase price per Optional Share shall be reduced by an amount per share equal to any dividends or distributions declared by the Company and payable on the Firm Shares but not payable on the Optional Shares. Any such election to purchase Optional Shares may be exercised only by written notice from you to the Company, given within a period of 30 calendar days after the date of this Agreement, setting forth the aggregate number of Optional Shares to be purchased and the date on which such Optional Shares are to be delivered, as determined by you but in no event earlier than the First Time of Delivery (as defined in Section 5 hereof) or, unless you and the Company otherwise agree in writing, earlier than two or later than ten business days after the date of such notice.

3. The Company hereby confirms its engagement of Lehman Brothers Inc. as, and Lehman Brothers Inc. hereby confirms its agreement with the Company to render services as, a “qualified independent underwriter” within the meaning of Rule 2720(b)(15) of the National Association of Securities Dealers, Inc. (the “NASD”) with respect to the offering and sale of the Shares. Lehman Brothers Inc., in its capacity as qualified independent underwriter and not otherwise, is referred to herein as the “QIU”.

4. Upon the authorization by you of the release of the Firm Shares, the several Underwriters propose to offer the Firm Shares for sale upon the terms and conditions set forth in the Prospectus.

5. (a) The Shares to be purchased by each Underwriter hereunder, in definitive form, and in such authorized denominations and registered in such names as Goldman, Sachs & Co. may request upon at least forty-eight hours’ prior notice to the Company shall be delivered by or on behalf of the Company to Goldman, Sachs & Co., through the facilities of the Depository Trust Company (“DTC”), for the account of such Underwriter, against payment by or on behalf of such Underwriter of the purchase price therefor by wire transfer of Federal (same-day) funds to the account specified by the Company to Goldman, Sachs & Co. at least forty-eight hours in advance. The Company will cause the certificates representing the Shares to be made available for checking and packaging at least twenty-four hours prior to the Time of Delivery (as defined below) at the office of DTC or its designated custodian (the “Designated Office”). The time and date of such delivery and payment shall be, with respect to the Firm Shares, 9:30 a.m., New York City time, on December 15, 2004 or such other time and date as Goldman, Sachs & Co. and the Company may agree upon in writing, and, with respect to the Optional Shares, 9:30 a.m., New York time, on the date specified by Goldman, Sachs & Co. in the written notice given by Goldman, Sachs & Co. of the Underwriters’ election to purchase such Optional Shares, or such other time and date as Goldman, Sachs & Co. and the Company may agree upon in writing. Such time and date for delivery of the Firm Shares is herein called the “First Time of Delivery”, such time and date for delivery of the Optional Shares, if not the First Time of Delivery, is herein called the “Second Time of Delivery”, and each such time and date for delivery is herein called a “Time of Delivery”.

(b) The documents to be delivered at each Time of Delivery by or on behalf of the parties hereto pursuant to Section 8 hereof, including the cross receipt for the Shares and any additional

documents requested by the Underwriters pursuant to Section 8 hereof, will be delivered at the offices of Akin Gump Strauss Hauer & Feld LLP, 1111 Louisiana St., 44th Floor, Houston, Texas 77002 (the “Closing Location”), and the Shares will be delivered at the Designated Office, all at such Time of Delivery. A meeting will be held at the Closing Location at 10:00 a.m., New York City time, on the New York Business Day next preceding such Time of Delivery, at which meeting the final drafts of the documents to be delivered pursuant to the preceding sentence will be available for review by the parties hereto. For the purposes of this Section 5, “New York Business Day” shall mean each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking institutions in New York are generally authorized or obligated by law or executive order to close.

6. The Company agrees with each of the Underwriters:

(a) To prepare the Prospectus in a form approved by you and to file such Prospectus pursuant to Rule 424(b) under the Act not later than the Commission’s close of business on the second business day following the date of the execution and delivery of this Agreement, or, if applicable, such earlier time as may be required by Rule 430A(a)(3) under the Act; to make no further amendment or any supplement to the Registration Statement or Prospectus which shall be disapproved by you promptly after reasonable notice thereof; to advise you, promptly after it receives notice thereof, of the time when any amendment to the Registration Statement has been filed or becomes effective or any supplement to the Prospectus or any amended Prospectus has been filed and to furnish you with copies thereof; to advise you, promptly after it receives notice thereof, of the issuance by the Commission of any stop order or of any order preventing or suspending the use of any Preliminary Prospectus or prospectus relating to the Shares, of the suspension of the qualification of the Shares for offering or sale in any jurisdiction, of the initiation or threatening of any proceeding for any such purpose, or of any request by the Commission for the amending or supplementing of the Registration Statement or Prospectus or for additional information; and, in the event of the issuance of any stop order or of any order preventing or suspending the use of any Preliminary Prospectus or prospectus relating to the Shares or suspending any such qualification, promptly to use its reasonable best efforts to obtain the withdrawal of such order;

(b) Promptly from time to time to take such action as you may reasonably request to qualify the Shares for offering and sale under the securities laws of such jurisdictions as you may request and to comply with such laws so as to permit the continuance of sales and dealings therein in such jurisdictions for as long as may be necessary to complete the distribution of the Shares, provided that in connection therewith the Company shall not be required to qualify as a foreign corporation, to become subject to general taxation or to file a general consent to service of process in any jurisdiction;

(c) Prior to 10:00 A.M., New York City time, on the New York Business Day next succeeding the date of this Agreement and from time to time, to furnish the Underwriters with written and electronic copies of the Prospectus in New York City in such quantities as you may reasonably request, and, if the delivery of a prospectus is required at any time prior to the expiration of nine months after the time of issue of the Prospectus in connection with the offering or sale of the Shares and if at such time any event shall have occurred as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made when such Prospectus is delivered, not misleading, or, if for any other reason it shall be necessary during such period to amend or supplement the Prospectus in order to

comply with the Act, to notify you and upon your request to prepare and furnish without charge to each Underwriter and to any dealer in securities as many written and electronic copies as you may from time to time reasonably request of an amended Prospectus or a supplement to the Prospectus which will correct such statement or omission or effect such compliance, and in case any Underwriter is required to deliver a prospectus in connection with sales of any of the Shares at any time nine months or more after the time of issue of the Prospectus, upon your request but at the expense of such Underwriter, to prepare and deliver to such Underwriter as many written and electronic copies as you may request of an amended or supplemented Prospectus complying with Section 10(a)(3) of the Act;

(d) To make generally available to its securityholders as soon as practicable, but in any event not later than eighteen months after the effective date of the Registration Statement (as defined in Rule 158(c) under the Act), an earnings statement of the Company and its subsidiaries (which need not be audited) complying with Section 11(a) of the Act and the rules and regulations thereunder (including, at the option of the Company, Rule 158);

(e) During the period beginning from the date hereof and continuing to and including the date 180 days after the date of the Prospectus (the initial “Lock-Up Period”), not to offer, sell, contract to sell or otherwise dispose of, except as provided hereunder any securities of the Company that are substantially similar to the Shares, including but not limited to any securities that are convertible into or exchangeable for, or that represent the right to receive, Stock or any such substantially similar securities (other than pursuant to stock option plans existing on, or upon the conversion or exchange of convertible or exchangeable securities outstanding as of, the date of this Agreement), without the prior written consent of Goldman, Sachs & Co.; provided, however, that if (1) during the last 17 days of the initial Lock-Up Period, the Company releases earnings results or announces material news or a material event or (2) prior to the expiration of the initial Lock-Up period, the Company announces that it will release earnings results during the 15-day period following the last day of the initial Lock-Up Period, then in each case the Lock-Up Period may be automatically extended until the expiration of the 18-day period beginning on the date of release of the earnings results or the announcement of the material news or material event, as applicable, unless Goldman, Sachs & Co. waives, in writing, such extension. The Company will provide the representatives and any co-managers and each stockholder subject to the Lock-Up Period pursuant to the lockup letters described in Section 8(m) with prior notice of any such announcement that gives rise to an extension of the Lock-up Period.

(f) To furnish to its stockholders as soon as practicable after the end of each fiscal year an annual report (including a balance sheet and statements of income, stockholders’ equity and cash flows of the Company and its consolidated subsidiaries certified by independent public accountants) and, as soon as practicable after the end of each of the first three quarters of each fiscal year (beginning with the fiscal quarter ending after the effective date of the Registration Statement), to make available to its stockholders consolidated summary financial information of the Company and its subsidiaries for such quarter in reasonable detail;

(g) During a period of five years from the effective date of the Registration Statement, to furnish to you copies of all reports or other communications (financial or other) furnished to stockholders, and to deliver to you (i) as soon as they are available, copies of any reports and financial statements furnished to or filed with the Commission or any national securities exchange on which any class of securities of the Company is listed, except that any reports or communications filed with the Commission and available through the Commission’s Electronic Data, Gathering,

Analysis and Retrieval (EDGAR) system need not be provided; and (ii) such additional information concerning the business and financial condition of the Company as you may from time to time reasonably request (such financial statements to be on a consolidated basis to the extent the accounts of the Company and its subsidiaries are consolidated in reports furnished to its stockholders generally or to the Commission); provided that any such information provided under clause (ii) shall be subject to such confidentiality and use restrictions as the Company shall reasonably impose;

(h) To use the net proceeds received by it from the sale of the Shares pursuant to this Agreement in the manner specified in the Prospectus under the caption “Use of Proceeds”;

(i) To use its best efforts to list, subject to notice of issuance, the Shares on the New York Stock Exchange (the “Exchange”);

(j) To file with the Commission such information on Form 10-Q or Form 10-K as may be required by Rule 463 under the Act;

(k) If the Company elects to rely upon Rule 462(b), the Company shall file a Rule 462(b) Registration Statement with the Commission in compliance with Rule 462(b) by 10:00 P.M., Washington, D.C. time, on the date of this Agreement, and the Company shall at the time of filing either pay to the Commission the filing fee for the Rule 462(b) Registration Statement or give irrevocable instructions for the payment of such fee pursuant to Rule 111(b) under the Act; and

(l) Upon request of any Underwriter, to furnish, or cause to be furnished, to such Underwriter an electronic version of the Company’s trademarks, servicemarks and corporate logo for use on the website, if any, operated by such Underwriter for the purpose of facilitating the on-line offering of the Shares (the “License”); provided, however, that the License shall be used solely for the purpose described above, is granted without any fee and may not be assigned or transferred.

7. The Company covenants and agrees with the several Underwriters that the Company will pay or cause to be paid the following: (i) the fees, disbursements and expenses of the Company’s counsel and accountants in connection with the registration of the Shares under the Act and all other expenses in connection with the preparation, printing and filing of the Registration Statement, any Preliminary Prospectus and the Prospectus and amendments and supplements thereto and the mailing and delivering of copies thereof to the Underwriters and dealers; (ii) the cost of printing or producing any Agreement among Underwriters, this Agreement, the Blue Sky Memorandum, closing documents (including any compilations thereof) and any other documents in connection with the offering, purchase, sale and delivery of the Shares; (iii) all expenses in connection with the qualification of the Shares for offering and sale under state securities laws as provided in Section 6(b) hereof, including the reasonable fees and disbursements of counsel for the Underwriters in connection with such qualification and in connection with the Blue Sky survey (iv) all fees and expenses in connection with listing the Shares on the New York Stock Exchange; (v) the filing fees incident to, and the reasonable fees and disbursements of counsel for the Underwriters in connection with, securing any required review by the National Association of Securities Dealers, Inc. of the terms of the sale of the Shares; (vi) the cost of preparing stock certificates; (vii) the cost and charges of any transfer agent or registrar; and (viii) all other costs and expenses incident to the performance of its obligations hereunder which are not otherwise specifically provided for in this Section. It is understood, however, that, except as provided in this Section, and Sections 9 and 13 hereof, the Underwriters will pay all of their own costs and expenses, including the fees of their counsel, stock

transfer taxes on resale of any of the Shares by them, and any advertising expenses connected with any offers they may make.

8. The obligations of the Underwriters hereunder, as to the Shares to be delivered at each Time of Delivery, shall be subject, in their discretion, to the condition that all representations and warranties and other statements of the Company herein are, at and as of such Time of Delivery, true and correct, the condition that the Company shall have performed all of its obligations hereunder theretofore to be performed, and the following additional conditions:

(a) The Prospectus shall have been filed with the Commission pursuant to Rule 424(b) within the applicable time period prescribed for such filing by the rules and regulations under the Act and in accordance with Section 6(a) hereof; if the Company has elected to rely upon Rule 462(b), the Rule 462(b) Registration Statement shall have become effective by 10:00 P.M., Washington, D.C. time, on the date of this Agreement; no stop order suspending the effectiveness of the Registration Statement or any part thereof shall have been issued and no proceeding for that purpose shall have been initiated or threatened by the Commission; and all requests for additional information on the part of the Commission shall have been complied with to your reasonable satisfaction;

(b) Vinson & Elkins L.L.P., counsel for the Underwriters, shall have furnished to you such written opinion or opinions, dated such Time of Delivery, with respect to certain matters as you may reasonably request, and such counsel shall have received such papers and information as they may reasonably request to enable them to pass upon such matters;

(c) Francis B. Barron, Senior Vice President—General Counsel of the Company, shall have furnished to you his written opinion, dated such Time of Delivery, in form and substance satisfactory to you, to the effect that:

(i) The Company is duly qualified as a foreign corporation for the transaction of business and is in good standing under the laws of each other jurisdiction in which it owns or leases properties or conducts any business so as to require such qualification or is subject to no material liability or disability by reason of failure to be so qualified in any such jurisdiction, except where the failure to be so qualified or to be in good standing in any such jurisdiction would not have a Material Adverse Effect (such counsel being entitled to rely in respect of the opinion in this clause upon opinions of local counsel and in respect of matters of fact upon certificates of officers of the Company, provided that such counsel shall state that they believe that both you and they are justified in relying upon such opinions and certificates);

(ii) To the best of such counsel’s knowledge and other than as set forth in the Prospectus, there are no legal or governmental proceedings pending to which the Company or any of its subsidiaries is a party or of which any property of the Company or any of its subsidiaries is the subject which, if determined adversely to the Company or any of its subsidiaries, would individually or in the aggregate have a Material Adverse Effect; and, to the best of such counsel’s knowledge, no such proceedings are threatened or contemplated by governmental authorities or threatened by others; and

(iii) Neither the Company nor any of its subsidiaries is (A) in violation of its Certificate of Incorporation or By-laws (in each case, as amended or restated) or (B) in default in the performance or observance of any material obligation, agreement, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement, lease or other

agreement or instrument to which it is a party or by which it or any of its properties may be bound, except in the case of (B), for such violations and defaults that would not result in a Material Adverse Effect.

(d) Patton Boggs LLP, counsel for the Company, shall have furnished to you its written opinion, dated such Time of Delivery, in the form and substance satisfactory to you, to the effect that:

(i) The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware, with corporate power and authority to own its properties and conduct its business as described in the Prospectus;

(ii) The Company has an authorized capitalization as set forth in the Prospectus, and all of the issued shares of capital stock of the Company (including the Shares being delivered at such Time of Delivery) have been duly and validly authorized and issued and are fully paid and non-assessable; and the Shares conform to the description of the Stock contained in the Prospectus;

(iii) Each subsidiary of the Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of its jurisdiction of incorporation; and all of the issued shares of capital stock of each such subsidiary have been duly and validly authorized and issued, are fully paid and non-assessable, and to the best of such counsel’s knowledge (except for directors’ qualifying shares and except as otherwise set forth in the Prospectus), are owned directly or indirectly by the Company, free and clear of all liens, encumbrances, equities or claims (such counsel being entitled to rely in respect of the opinion in this clause upon opinions of local counsel and in respect to matters of fact upon certificates of officers of the Company or its subsidiaries, provided that such counsel shall state that they believe that both you and they are justified in relying upon such opinions and certificates);

(iv) The issue and sale of the Shares being delivered at such Time of Delivery by the Company and the compliance by the Company with all of the provisions of this Agreement and the consummation of the transactions herein contemplated will not result in any violations of any statute of the State of Colorado or any order, rule or regulation known to such counsel of any Colorado court, governmental agency or body having jurisdiction over the Company or any of its subsidiaries or any of their properties, except for such violations that would not result in a Material Adverse Effect;

(v) No consent, approval, authorization, order, registration or qualification of or with any such court, governmental agency or body of the State of Colorado is required for the issue and sale of the Shares or the consummation by the Company of the transactions contemplated by this Agreement, except the registration under the Act and the Exchange Act of the Shares, and such consents, approvals, authorizations, registrations or qualifications as may be required under state securities or Blue Sky laws in connection with the purchase and distribution of the Shares by the Underwriters; and

(vi) Each of the Registration Statement and the Prospectus (other than the financial statements and related schedules and other financial data therein and the information pertaining to oil and natural gas reserves therein, as to which such counsel need express no view) at the time it was filed with the Commission, appeared on its face to be appropriately responsive in all material respects to the requirements of the Act and the rules and regulations

thereunder; although they are not passing upon, do not assume any responsibility for and make no representation that they have independently verified the accuracy, completeness or fairness of the statements contained in the Registration Statement or the Prospectus, no information has come to their attention that causes them to believe that, as of its effective date, the Registration Statement (other than the financial statements and related schedules and other financial data therein and the information pertaining to oil and natural gas reserves therein, as to which such counsel need express no view) contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading or that, as of its date, the Prospectus (other than the financial statements and related schedules and other financial data therein and the information pertaining to oil and natural gas reserves therein, as to which such counsel need express no view) contained an untrue statement of a material fact or omitted to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading or that, as of such Time of Delivery, either the Registration Statement or the Prospectus (other than the financial statements and related schedules and other financial data therein and the information pertaining to oil and natural gas reserves therein, as to which such counsel need express no view) contains an untrue statement of a material fact or omits to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; and they do not know of any amendment to the Registration Statement required to be filed or of any contracts or other documents of a character required to be filed as an exhibit to the Registration Statement or required to be described in the Registration Statement or the Prospectus which are not filed or described as required.

(e) Akin Gump Strauss Hauer & Feld LLP, special counsel for the Company, shall have furnished to you its written opinion, dated such Time of Delivery, in the form and substance satisfactory to you, to the effect that:

(i) This Agreement has been duly authorized, executed and delivered by the Company;

(ii) The issue and sale of the Shares being delivered at such Time of Delivery by the Company and the compliance by the Company with all of the provisions of this Agreement and the consummation of the transactions herein contemplated (A) will not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, any agreement or instrument filed as an exhibit to the Registration Statement, (B) will not result in any violation of the provisions of the Restated Certificate of Incorporation or By-laws of the Company, and (C) will not result in any violations of any United States federal statute or the Delaware General Corporation Law or any order, rule or regulation known to such counsel of any United States federal or Delaware (solely with respect to the Delaware General Corporation Law) court, governmental agency or body having jurisdiction over the Company or any of its subsidiaries or any of their properties, except for such violations that would not result in a Material Adverse Effect;

(iii) No consent, approval, authorization, order, registration or qualification of or with any such court, governmental agency or body of the United States of America or the State of Delaware (solely with respect to the Delaware General Corporation Law) is required for the issue and sale of the Shares or the consummation by the Company of the transactions

contemplated by this Agreement, except the registration under the Act and the Exchange Act of the Shares, and such consents, approvals, authorizations, registrations or qualifications as may be required under state securities or Blue Sky laws in connection with the purchase and distribution of the Shares by the Underwriters;

(iv) The statements set forth in the Prospectus under the caption “Description of Capital Stock”, insofar as they purport to constitute a summary of the terms of the Stock and under the caption “Underwriting”, insofar as they purport to describe the provisions of the United States federal laws and the Delaware General Corporation Law and documents referred to therein, fairly and accurately summarize and describe such matters in all material respects;

(v) The Company is not an “investment company”, as such term is defined in the Investment Company Act;

(vi) The Registration Statement, including any Rule 462(b) Registration Statement, has been declared effective under the Act; any required filing of the Prospectus pursuant to Rule 424(b) has been made in the manner and within the time period required by Rule 424(b); and, to the best of our knowledge, no stop order suspending the effectiveness of the Registration Statement or any Rule 462(b) Registration Statement has been issued under the Act and no proceedings for that purpose have been instituted or are pending or threatened by the Commission;

(vii) The form of certificate used to evidence the Common Stock complies in all material respects with the Delaware General Corporation Law, with any applicable requirements of the Restated Certificate of Incorporation and By-laws of the Company and the requirements of the New York Stock Exchange; and

(viii) Each of the Registration Statement and the Prospectus (other than the financial statements and related schedules and other financial data therein and the information pertaining to oil and natural gas reserves therein, as to which such counsel need express no view) at the time it was filed with the Commission, appeared on its face to be appropriately responsive in all material respects to the requirements of the Act and the rules and regulations thereunder; although they are not passing upon, do not assume any responsibility for and make no representation that they have independently verified the accuracy, completeness or fairness of the statements contained in the Registration Statement or the Prospectus, except for those referred to in the opinion in subsection (iv) of this section 8(e), no information has come to their attention that causes them to believe that, as of its effective date, the Registration Statement (other than the financial statements and related schedules and other financial data therein and the information pertaining to oil and natural gas reserves therein, as to which such counsel need express no view) contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading or that, as of its date, the Prospectus (other than the financial statements and related schedules and other financial data therein and the information pertaining to oil and natural gas reserves therein, as to which such counsel need express no view) contained an untrue statement of a material fact or omitted to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading or that, as of such Time of Delivery, either the

Registration Statement or the Prospectus (other than the financial statements and related schedules and other financial data therein and the information pertaining to oil and natural gas reserves therein, as to which such counsel need express no view) contains an untrue statement of a material fact or omits to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; and they do not know of any contracts or other documents of a character required to be filed as an exhibit to the Registration Statement or required to be described in the Registration Statement or the Prospectus which are not filed or described as required;

(f) On the date of the Prospectus at a time prior to the execution of this Agreement, at 9:30 a.m., New York City time, on the effective date of any post-effective amendment to the Registration Statement filed subsequent to the date of this Agreement and also at each Time of Delivery, Deloitte & Touche LLP shall have furnished to you a letter or letters, dated the respective dates of delivery thereof, in form and substance satisfactory to you, to the effect set forth in Annex I hereto (the executed copy of the letter delivered prior to the execution of this Agreement is attached as Annex I(a) hereto and a draft of the form of letter to be delivered on the effective date of any post-effective amendment to the Registration Statement and as of each Time of Delivery is attached as Annex I(b) hereto);

(g) On the date of the Prospectus at a time prior to the execution of this Agreement and at 9:30 a.m., New York City time, on the effective date of any post-effective amendment to the Registration Statement filed subsequent to the date of this Agreement, KPMG LLP shall have furnished to you a letter or letters, dated the respective dates of delivery thereof, in form and substance satisfactory to you, stating that they have audited Statement of Revenues and Direct Operating Expenses of the Wind River, Powder River and Williston Acquisition Properties for the period from January 1, 2002 through December 15, 2002.

(h) On the date of the Prospectus at a time prior to the execution of this Agreement and at 9:30 a.m., New York City time, on the effective date of any post-effective amendment to the Registration Statement filed subsequent to the date of this Agreement, each of Ryder Scott Company, L.P. and Netherland, Sewell & Associates, Inc. shall have furnished to you a letter or letters, dated the respective dates of delivery thereof, in form and substance satisfactory to you, to the effect set forth in Annex II hereto;

(i) (i) Neither the Company nor any of its subsidiaries shall have sustained since the date of the latest audited financial statements included in the Prospectus any loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Prospectus, and (ii) since the respective dates as of which information is given in the Prospectus there shall not have been any change in the capital stock or long-term debt of the Company or any of its subsidiaries or any change, or any development involving a prospective change, in or affecting the general affairs, management, financial position, stockholders’ equity or results of operations of the Company and its subsidiaries, otherwise than as set forth or contemplated in the Prospectus, the effect of which, in any such case described in clause (i) or (ii), is in the judgment of the Representatives so material and adverse as to make it impracticable or inadvisable to proceed with the public offering or the delivery of the Shares being delivered at such Time of Delivery on the terms and in the manner contemplated in the Prospectus;

(j) On or after the date hereof (i) no downgrading shall have occurred in the rating accorded the Company’s debt securities or preferred stock by any “nationally recognized statistical rating organization”, as that term is defined by the Commission for purposes of Rule 436(g)(2) under the Act, and (ii) no such organization shall have publicly announced that it has under surveillance or review, with possible negative implications, its rating of any of the Company’s debt securities or preferred stock;

(k) On or after the date hereof there shall not have occurred any of the following: (i) a suspension or material limitation in trading in securities generally on the New York Stock Exchange; (ii) a suspension or material limitation in trading in the Company’s securities on the New York Stock Exchange; (iii) a general moratorium on commercial banking activities declared by either Federal or New York State authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States; (iv) the outbreak or escalation of hostilities involving the United States or the declaration by the United States of a national emergency or war or (v) the occurrence of any other calamity or crisis or any change in financial, political or economic conditions in the United States or elsewhere, if the effect of any such event specified in clause (iv) or (v) in the judgment of the Representatives makes it impracticable or inadvisable to proceed with the public offering or the delivery of the Shares being delivered at such Time of Delivery on the terms and in the manner contemplated in the Prospectus;

(l) The Shares to be sold at such Time of Delivery shall have been duly listed, subject to notice of issuance, on the Exchange;

(m) The Company has obtained and delivered to the Underwriters executed copies of an agreement substantially in the form attached hereto as Annex III(a) from the officers and directors of the Company and each of the stockholders named on Annex III(b) hereto;

(n) The Company shall have complied with the provisions of Section 6(c) hereof with respect to the furnishing of prospectuses on the New York Business Day next succeeding the date of this Agreement; and

(o) The Company shall have furnished or caused to be furnished to you at such Time of Delivery certificates of officers of the Company satisfactory to you as to the accuracy of the representations and warranties of the Company herein at and as of such Time of Delivery, as to the performance by the Company of all of its obligations hereunder to be performed at or prior to such Time of Delivery, as to the matters set forth in subsections (a) and (i) of this Section and as to such other matters as you may reasonably request.

9. (a) The Company will indemnify and hold harmless each Underwriter against any losses, claims, damages or liabilities, joint or several, to which such Underwriter may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in any Preliminary Prospectus, the Registration Statement or the Prospectus, or any amendment 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 will reimburse each Underwriter for any legal or other expenses reasonably incurred by such Underwriter in connection with investigating or defending any such action or claim as such expenses are incurred; provided, however, that the Company shall 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 an untrue statement or alleged untrue statement or omission or alleged omission made in any Preliminary Prospectus, the Registration Statement or the Prospectus or any such amendment or supplement in reliance upon and in conformity with written information furnished to the Company by any Underwriter through Goldman, Sachs & Co. expressly for use therein.

(b) Each Underwriter will indemnify and hold harmless the Company against any losses, claims, damages or liabilities to which the Company may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in any Preliminary Prospectus, the Registration Statement or the Prospectus, or any amendment 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, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in any Preliminary Prospectus, the Registration Statement or the Prospectus or any such amendment or supplement in reliance upon and in conformity with written information furnished to the Company by such Underwriter through Goldman, Sachs & Co. expressly for use therein; and will reimburse the Company for any legal or other expenses reasonably incurred by the Company in connection with investigating or defending any such action or claim as such expenses are incurred.

(c) Promptly after receipt by an indemnified party under subsection (a) or (b) above of notice of the commencement of any action, such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party under such subsection, notify the indemnifying party in writing of the commencement thereof; but the omission so to notify the indemnifying party shall not relieve it from any liability which it may have to any indemnified party otherwise than under such subsection. In case any such action shall be brought against any indemnified party and it shall notify the indemnifying party of the commencement thereof, the indemnifying party shall be entitled to participate therein and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to the indemnifying party), and, after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party shall not be liable to such indemnified party under such subsection for any legal expenses of other counsel or any other expenses, in each case subsequently incurred by such indemnified party, in connection with the defense thereof other than reasonable costs of investigation. No indemnifying party shall, without the written consent of the indemnified party, effect the settlement or compromise of, or consent to the entry of any judgment with respect to, any pending or threatened action or claim in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified party is an actual or potential party to such action or claim) unless such settlement, compromise or judgment (i) includes an unconditional release of the indemnified party from all liability arising out of such action or claim 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 any indemnified party.

(d) If the indemnification provided for in this Section 9 is unavailable to or insufficient to hold harmless an indemnified party under subsection (a) or (b) above in respect of any losses, claims, damages or liabilities (or actions in respect thereof) referred to therein, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such losses,

claims, damages or liabilities (or actions in respect thereof) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Shares. If, however, the allocation provided by the immediately preceding sentence is not permitted by applicable law or if the indemnified party failed to give the notice required under subsection (c) above, then each indemnifying party shall contribute to such amount paid or payable by such indemnified party in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company on the one hand and the Underwriters on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities (or actions in respect thereof), as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company bear to the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover page of the Prospectus. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company on the one hand or the Underwriters on the other and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Company and the Underwriters agree that it would not be just and equitable if contributions pursuant to this subsection (d) were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to above in this subsection (d). The amount paid or payable by an indemnified party as a result of the losses, claims, damages or liabilities (or actions in respect thereof) referred to above in this subsection (d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this subsection (d), no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Shares underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. 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. The Underwriters’ obligations in this subsection (d) to contribute are several in proportion to their respective underwriting obligations and not joint.

(e) The obligations of the Company under this Section 9 shall be in addition to any liability which the Company may otherwise have and shall extend, upon the same terms and conditions, to each person, if any, who controls any Underwriter within the meaning of the Act; and the obligations of the Underwriters under this Section 9 shall be in addition to any liability which the respective Underwriters may otherwise have and shall extend, upon the same terms and conditions, to each officer and director of the Company (including any person who, with his or her consent, is named in the Registration Statement as about to become a director of the Company) and to each person, if any, who controls the Company within the meaning of the Act.

10. (a) If any Underwriter shall default in its obligation to purchase the Shares which it has agreed to purchase hereunder at a Time of Delivery, you may in your discretion arrange for you or another party or other parties to purchase such Shares on the terms contained herein. If within thirty-six hours after such default by any Underwriter you do not arrange for the purchase of such

Shares, then the Company shall be entitled to a further period of thirty-six hours within which to procure another party or other parties satisfactory to you to purchase such Shares on such terms. In the event that, within the respective prescribed periods, you notify the Company that you have so arranged for the purchase of such Shares, or the Company notifies you that it has so arranged for the purchase of such Shares, you or the Company shall have the right to postpone such Time of Delivery for a period of not more than seven days, in order to effect whatever changes may thereby be made necessary in the Registration Statement or the Prospectus, or in any other documents or arrangements, and the Company agrees to file promptly any amendments to the Registration Statement or the Prospectus which in your opinion may thereby be made necessary. The term “Underwriter” as used in this Agreement shall include any person substituted under this Section with like effect as if such person had originally been a party to this Agreement with respect to such Shares.

(b) If, after giving effect to any arrangements for the purchase of the Shares of a defaulting Underwriter or Underwriters by you and the Company as provided in subsection (a) above, the aggregate number of such Shares which remains unpurchased does not exceed one-eleventh of the aggregate number of all the Shares to be purchased at such Time of Delivery, then the Company shall have the right to require each non-defaulting Underwriter to purchase the number of shares which such Underwriter agreed to purchase hereunder at such Time of Delivery and, in addition, to require each non-defaulting Underwriter to purchase its pro rata share (based on the number of Shares which such Underwriter agreed to purchase hereunder) of the Shares of such defaulting Underwriter or Underwriters for which such arrangements have not been made; but nothing herein shall relieve a defaulting Underwriter from liability for its default.

(c) If, after giving effect to any arrangements for the purchase of the Shares of a defaulting Underwriter or Underwriters by you and the Company as provided in subsection (a) above, the aggregate number of such Shares which remains unpurchased exceeds one-eleventh of the aggregate number of all the Shares to be purchased at such Time of Delivery, or if the Company shall not exercise the right described in subsection (b) above to require non-defaulting Underwriters to purchase Shares of a defaulting Underwriter or Underwriters, then this Agreement (or, with respect to the Second Time of Delivery, the obligations of the Underwriters to purchase and of the Company to sell the Optional Shares) shall thereupon terminate, without liability on the part of any non-defaulting Underwriter or the Company, except for the expenses to be borne by the Company and the Underwriters as provided in Section 7 hereof and the indemnity and contribution agreements in Section 9 hereof; but nothing herein shall relieve a defaulting Underwriter from liability for its default.

11. (a) The Company will indemnify and hold harmless Lehman Brothers Inc., in its capacity as QIU, against any losses, claims, damages or liabilities, joint or several, to which the QIU may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon (i) an untrue statement or alleged untrue statement of a material fact contained in any Preliminary Prospectus, the Registration Statement or the Prospectus, or any amendment or supplement thereto, (ii) 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 or (ii) any act or omission to act or any alleged act or omission to act by Lehman Brothers Inc. as QIU in connection with any transaction contemplated by this Agreement or undertaken in preparing for the purchase, sale and delivery of the Shares, except as to this clause (iii) to the extent that any such loss, claim, damage or liability results from the gross negligence or bad faith of Lehman Brothers Inc. in performing the services as QIU, and will reimburse

the QIU for any legal or other expenses reasonably incurred by the QIU in connection with investigating or defending any such action or claim as such expenses are incurred; provided, however, that the Company shall 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 an untrue statement or alleged untrue statement or omission or alleged omission made in any Preliminary Prospectus, the Registration Statement or the Prospectus or any such amendment or supplement in reliance upon and in conformity with written information furnished to the Company by the Underwriters or the QIU expressly for use therein.

(b) Promptly after receipt by the QIU under subsection (a) above of notice of the commencement of any action, the QIU shall, if a claim in respect thereof is to be made against the Company under such subsection, notify the Company in writing of the commencement thereof; but the omission so to notify the Company shall not relieve it from any liability which it may have to the QIU otherwise than under such subsection. In case any such action shall be brought against the QIU and it shall notify the Company of the commencement thereof, the Company shall be entitled to participate therein and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to the QIU (who shall not, except with the consent of the QIU, be counsel to the Company), and, after notice from the indemnifying party to the QIU of its election so to assume the defense thereof, the indemnifying party shall not be liable to the QIU under such subsection for any legal expenses of other counsel or any other expenses, in each case subsequently incurred by the QIU, in connection with the defense thereof other than reasonable costs of investigation. The Company shall not, without the written consent of the indemnified party, effect the settlement or compromise of, or consent to the entry of any judgment with respect to, any pending or threatened action or claim in respect of which indemnification or contribution may be sought hereunder (whether or not the QIU is an actual or potential party to such action or claim) unless such settlement, compromise or judgment (i) includes an unconditional release of the QIU from all liability arising out of such action or claim 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 QIU.

(c) If the indemnification provided for in this Section 11 is unavailable to or insufficient to hold harmless Lehman Brothers Inc., in its capacity as QIU, under subsection (a) above in respect of any losses, claims, damages or liabilities (or actions in respect thereof) referred to therein, then the Company shall contribute to the amount paid or payable by the QIU as a result of such losses, claims, damages or liabilities (or actions in respect thereof) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the QIU on the other from the offering of the Shares. If, however, the allocation provided by the immediately preceding sentence is not permitted by applicable law or if the QIU failed to give the notice required under subsection (b) above, then the Company shall contribute to such amount paid or payable by the QIU in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company on the one hand and the QIU on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities (or actions in respect thereof), as well as any other relevant equitable considerations. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company on the one hand or the QIU on the other and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Company and the QIU agree that it would not be just and equitable if contributions pursuant to this subsection (c)

were determined by pro rata allocation or by any other method of allocation which does not take account of the equitable considerations referred to above in this subsection (c). The amount paid or payable by the QIU as a result of the losses, claims, damages or liabilities (or actions in respect thereof) referred to above in this subsection (c) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. 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.

(d) The obligations of the Company under this Section 11 shall be in addition to any liability which the Company may otherwise have and shall extend, upon the same terms and conditions, to each person, if any, who controls the QIU within the meaning of the Act.

12. The respective indemnities, agreements, representations, warranties and other statements of the Company and the several Underwriters, as set forth in this Agreement or made by or on behalf of them, respectively, pursuant to this Agreement, shall remain in full force and effect, regardless of any investigation (or any statement as to the results thereof) made by or on behalf of any Underwriter or any controlling person of any Underwriter, or the Company, or any officer or director or controlling person of the Company, and shall survive delivery of and payment for the Shares.

Anything herein to the contrary notwithstanding, the indemnity agreement of the Company in subsection (a) of Section 9 hereof, the representations and warranties in subsections (b) and (c) of Section 1 hereof and any representation or warranty as to the accuracy of the Registration Statement or the Prospectus contained in any certificate furnished by the Company pursuant to Section 8 hereof, insofar as they may constitute a basis for indemnification for liabilities (other than payment by the Company of expenses incurred or paid in the successful defense of any action, suit or proceeding) arising under the Act, shall not extend to the extent of any interest therein of a controlling person or partner of an Underwriter who is a director, officer or controlling person of the Company when the Registration Statement has become effective, except in each case to the extent that an interest of such character shall have been determined by a court of appropriate jurisdiction as not against public policy as expressed in the Act. Unless in the opinion of counsel for the Company the matter has been settled by controlling precedent, the Company will, if a claim for such indemnification is asserted, submit to a court of appropriate jurisdiction the question of whether such interest is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

13. If this Agreement shall be terminated pursuant to Section 10 hereof, the Company shall not then be under any liability to any Underwriter except as provided in Sections 7 and 9 hereof; but, if for any other reason, any Shares are not delivered by or on behalf of the Company as provided herein, the Company will reimburse the Underwriters through you for all out-of-pocket expenses approved in writing by you, including fees and disbursements of counsel, reasonably incurred by the Underwriters in making preparations for the purchase, sale and delivery of the Shares not so delivered, but the Company shall then be under no further liability to any Underwriter except as provided in Sections 7 and 9 hereof.

14. In all dealings hereunder, you shall act on behalf of each of the Underwriters, and the parties hereto shall be entitled to act and rely upon any statement, request, notice or agreement on

behalf of any Underwriter made or given by you jointly or by Goldman, Sachs & Co. on behalf of you as the representatives.

All statements, requests, notices and agreements hereunder shall be in writing, and if to the Underwriters shall be delivered or sent by mail, telex or facsimile transmission to you as the representatives in care of Goldman, Sachs & Co., 85 Broad Street, New York, New York 10004, Attention: Registration Department; and if to the Company shall be delivered or sent by mail to the address of the Company set forth in the Registration Statement, Attention: Secretary; provided, however, that any notice to an Underwriter pursuant to Section 9(c) hereof shall be delivered or sent by mail, telex or facsimile transmission to such Underwriter at its address set forth in its Underwriters’ Questionnaire, or telex constituting such Questionnaire, which address will be supplied to the Company by you upon request. Any such statements, requests, notices or agreements shall take effect upon receipt thereof.

15. This Agreement shall be binding upon, and inure solely to the benefit of, the Underwriters, the Company and, to the extent provided in Sections 9 and 12 hereof, the officers and directors of the Company and each person who controls the Company or any Underwriter, and their respective heirs, executors, administrators, successors and assigns, and no other person shall acquire or have any right under or by virtue of this Agreement. No purchaser of any of the Shares from any Underwriter shall be deemed a successor or assign by reason merely of such purchase.

16. Time shall be of the essence of this Agreement. As used herein, the term “business day” shall mean any day when the Commission’s office in Washington, D.C. is open for business.

17. This Agreement shall be governed by and construed in accordance with the laws of the State of New York.

18. This Agreement may be executed by any one or more of the parties hereto in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same instrument.

19. The Company is authorized, subject to applicable law, to disclose any and all aspects of this potential transaction that are necessary to support any U.S. federal income tax benefits expected to be claimed with respect to such transaction, and all materials of any kind (including tax opinions and other tax analyses) related to those benefits, without the Underwriters imposing any limitation of any kind.

If the foregoing is in accordance with your understanding, please sign and return to us twelve (12) counterparts hereof, and upon the acceptance hereof by you, on behalf of each of the Underwriters, this letter and such acceptance hereof shall constitute a binding agreement between each of the Underwriters and the Company. It is understood that your acceptance of this letter on behalf of each of the Underwriters is pursuant to the authority set forth in a form of Agreement among Underwriters, the form of which shall be submitted to the Company for examination upon request, but without warranty on your part as to the authority of the signers thereof.


		Very truly yours,

		Bill Barrett Corporation

		By:		/s/ William J. Barrett

				Name: William J. Barrett
				Title: Chief Executive Officer

Accepted as of the date hereof:

Goldman, Sachs & Co.
J. P. Morgan Securities Inc.
Lehman Brothers Inc.
Credit Suisse First Boston LLC
Morgan Stanley & Co. Incorporated
Petrie Parkman & Co., Inc.
First Albany Capital Inc.


By:		/s/ Goldman, Sachs & Co.

		(Goldman, Sachs & Co.)

On behalf of each of the Underwriters

SCHEDULE I


			Number of Optional
			Shares to be
	Total Number of		Purchased if
	Firm Shares		Maximum Option
Underwriter	to be Purchased		Exercised
Goldman, Sachs & Co.		4,585,180		687,777
J. P. Morgan Securities Inc.		2,292,590		343,889
Lehman Brothers Inc.		2,292,590		343,889
Credit Suisse First Boston LLC		1,179,046		176,856
Morgan Stanley & Co. Incorporated		1,179,047		176,857
Petrie Parkman & Co., Inc.		1,179,047		176,857
First Albany Capital Inc.		292,500		43,875

Total		13,000,000		1,950,000