INTEGRYS ENERGY GROUP, INC. Underwriting Agreement

Exhibit 1

EXECUTION COPY

INTEGRYS ENERGY GROUP, INC.

4.170% Senior Notes Due November 1, 2020

Underwriting Agreement

New York, New York

November 9, 2010

To the Representatives named in

Schedule I hereto of the several

Underwriters named in

Schedule II hereto

Ladies and Gentlemen:

Integrys Energy Group, Inc., a corporation organized under the laws of Wisconsin (the “Company”), proposes to sell to the several underwriters named in Schedule II hereto (the “Underwriters”), for whom you (the “Representatives”) are acting as representatives, the principal amount of its securities identified in Schedule I hereto (the “Securities”), to be issued under an Indenture, dated as of October 1, 1999, between the Company and U.S. Bank National Association, as trustee (the “Trustee”), as amended and supplemented to the date hereof (as so amended and supplemented, the “Original Indenture”) and to be further supplemented by the Fifth Supplemental Indenture, dated as of November 1, 2010, creating the series in which the Securities are to be issued (the “Supplemental Indenture”). The term “Indenture,” as used herein, means the Original Indenture as supplemented by the Supplemental Indenture. 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. Any reference herein to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Final Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 which were filed under the Exchange Act on or before the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any Preliminary Prospectus or the Final Prospectus, as the case may be; and any reference herein to the terms “amend,” “amendment” or “supplement” with respect to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Final Prospectus shall be deemed to refer to and include the filing of any document under the Exchange Act after the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any Preliminary Prospectus or the Final Prospectus, as the case may be, deemed to be incorporated therein by reference. Certain terms used herein are defined in Section 20 hereof.

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

(a) Registration Statement and Prospectuses. The Company meets the requirements for use of Form S-3 under the Act and has prepared and filed with the Commission

an automatic shelf registration statement, as defined in Rule 405 (the file number of which is set forth in Schedule I hereto) on Form S-3, including a related Base Prospectus, for registration under the Act of the offering and sale of the Securities. Such Registration Statement, including any amendments thereto filed prior to the Execution Time, became effective upon filing. The Company may have filed with the Commission, as part of an amendment to the Registration Statement or pursuant to Rule 424(b), one or more Preliminary Prospectuses relating to the Securities, each of which has previously been furnished to you. The Company will file with the Commission a Final Prospectus relating to the Securities in accordance with Rule 424(b). As filed, such Final Prospectus shall contain all information required by the Act and the rules thereunder, and, except to the extent the Representatives shall agree in writing to a modification, shall be in all substantive respects in the form furnished to you prior to the Execution Time or, to the extent not completed at the Execution Time, shall contain only such specific additional information and other changes (beyond that contained in the Base Prospectus and any Preliminary Prospectus) as the Company has advised you, prior to the Execution Time, will be included or made therein. The Registration Statement, at the Execution Time, meets the requirements set forth in Rule 415(a)(1)(x).

(b) No Material Misstatements or Omissions. On each Effective Date, the Registration Statement did, and when the Final Prospectus is first filed in accordance with Rule 424(b) and on the Closing Date (as defined herein), the Final Prospectus (and any supplement thereto) will, comply in all material respects with the applicable requirements of the Act, the Exchange Act and the Trust Indenture Act and the respective rules thereunder; on each Effective Date and at the Execution Time, the Registration Statement did not and will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein not misleading; on the Effective Date and on the Closing Date the Indenture did or will comply in all material respects with the applicable requirements of the Trust Indenture Act and the rules thereunder; and on the date of any filing pursuant to Rule 424(b) and on the Closing Date, the Final Prospectus (together with any supplement thereto) will not include any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that the Company makes no representations or warranties as to (i) that part of the Registration Statement which shall constitute the Statement of Eligibility and Qualification (Form T-1) under the Trust Indenture Act of the Trustee or (ii) the information contained in or omitted from the Registration Statement or the Final Prospectus (or any supplement thereto) in reliance upon and in conformity with information furnished in writing to the Company by or on behalf of any Underwriter through the Representatives specifically for inclusion in the Registration Statement or the Final Prospectus (or any supplement thereto), it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in Section 8 hereof.

(c) Disclosure Package. The (i) Disclosure Package and (ii) each electronic road show, if any, when taken together as a whole with the Disclosure Package, does not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from the Disclosure Package based upon and in conformity with written information furnished to the

Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in Section 8(b) hereof.

(d) Status of Company as Well-Known Seasoned Issuer. (i) At the time of filing the Registration Statement, (ii) at the time of the most recent amendment thereto for the purposes of complying with Section 10(a)(3) of the Act (whether such amendment was by post-effective amendment, incorporated report filed pursuant to Sections 13 or 15(d) of the Exchange Act or form of prospectus), (iii) at the time the Company or any person acting on its behalf (within the meaning, for this clause only, of Rule 163(c)) made any offer relating to the Securities in reliance on the exemption in Rule 163, and (iv) at the Execution Time (with such date being used as the determination date for purposes of this clause (iv)), the Company was or is (as the case may be) a “well-known seasoned issuer” as defined in Rule 405. The Company agrees to pay the fees required by the Commission relating to the Securities within the time required by Rule 456(b)(1) without regard to the proviso therein and otherwise in accordance with Rules 456(b) and 457(r).

(e) Absence of Status as Ineligible Issuer. (i) At the earliest time after the filing of the Registration Statement that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2)) of the Securities and (ii) as of the Execution Time (with such date being used as the determination date for purposes of this clause (ii)), the Company was not and is not an Ineligible Issuer (as defined in Rule 405), without taking account of any determination by the Commission pursuant to Rule 405 that it is not necessary that the Company be considered an Ineligible Issuer.

(f) Issuer Free Writing Prospectuses. Each Issuer Free Writing Prospectus and the final term sheet prepared and filed pursuant to Section 5(b) hereto does not include any information that conflicts with the information contained in the Registration Statement, including any document incorporated therein by reference and any prospectus supplement deemed to be a part thereof that has not been superseded or modified. The foregoing sentence does not apply to statements in or omissions from any Issuer Free Writing Prospectus based upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in Section 8(b) hereof.

(g) Organization and Good Standing of the Company. The Company has been duly organized and is validly existing as a corporation under the laws of the State of Wisconsin with power and authority (corporate and other) to own, lease and operate its properties and conduct its business as described in the Registration Statement, the Disclosure Package and the Final Prospectus; the Company has not filed Articles of Dissolution with the Department of Financial Institutions of the State of Wisconsin, and no grounds exist for the Department of Financial Institutions of the State of Wisconsin to dissolve such corporation administratively pursuant to the provisions of the Wisconsin Business Corporation Law; the Company is duly qualified as a foreign corporation to transact business and is in good standing in each jurisdiction in which its ownership or lease of properties or the conduct of its business requires such qualification, except where the failure to so qualify and be in good standing would

not, individually or in the aggregate, have a material adverse effect on the performance of this Agreement or the consummation of any of the transactions contemplated hereby or the condition (financial or otherwise), earnings, business or properties of the Company and its subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business (a “Material Adverse Effect”).

(h) Organization and Good Standing of Covered Subsidiaries. Each of Wisconsin Public Service Corporation, a Wisconsin corporation (“WPS”), The Peoples Gas Light and Coke Company, an Illinois corporation (“PGL”), Integrys Energy Services, Inc., a Wisconsin corporation (“TEGE”), Michigan Gas Utilities Corporation, a Delaware corporation (“MGU”), Minnesota Energy Resources Corporation, a Delaware corporation (“MERC”), Peoples Energy Corporation, an Illinois corporation (“PEC”), North Shore Gas Company, an Illinois corporation (“NSG”), and WPS Investments, LLC, a Wisconsin limited liability company ( (“WPSI” and together with WPS, PGL, TEGE, MGU, MERC, PEC, and NSG, the “Covered Subsidiaries”) has been duly organized and is validly existing under the laws of the jurisdiction of its incorporation or organization and has corporate or limited liability power and authority to own, lease and operate its properties and conduct its business as described in the Registration Statement, the Disclosure Package and the Final Prospectus; no Covered Subsidiary which is organized under the laws of the State of Wisconsin has filed Articles of Dissolution with the Department of Financial Institutions of the State of Wisconsin, and no grounds exist for the Department of Financial Institutions of the State of Wisconsin to dissolve any such Covered Subsidiary administratively pursuant to the provisions of the Wisconsin Business Corporation Law or Chapter 183 of the Wisconsin Statutes, as applicable; each Covered Subsidiary is duly qualified as a foreign corporation to transact business and is in good standing in each jurisdiction in which the ownership or lease of properties or the conduct of its business requires such qualification, except where the failure to so qualify or to be in good standing would not result in a Material Adverse Effect. The Company has no subsidiaries which either individually or considered in the aggregate as a single subsidiary constitute a “significant subsidiary” as defined in Rule 405 under the Act, other than the Covered Subsidiaries.

(i) Ownership of Covered Subsidiaries. All of the outstanding shares of capital stock or other equity interests of the Covered Subsidiaries (i) have been duly and validly authorized and issued and are fully paid and nonassessable, and (ii) other than the preferred stock of WPS, are owned directly or indirectly by the Company, free and clear of any lien, charge, encumbrance, security interest, restriction on voting or transfer or any other claim of any third party.

(j) Accuracy of Description of Certain Descriptions in the Registration Statement and Prospectuses; Exhibits. The descriptions in the Registration Statement, the Disclosure Package and the Final Prospectus of (i) statutes, (ii) legal, governmental and regulatory proceedings relating to the Company, and (iii) contracts and other documents are accurate in all material respects; and the statements incorporated by reference in the Preliminary Prospectus and the Final Prospectus from Item 3 of Part I of the Company’s Annual Report on Form 10-K for the year ended 2009, to the extent that they constitute summaries of matters of law or regulation or legal conclusions, fairly summarize the matters described therein in all material respects. There is no franchise, contract or other document of a character required to be described in the Registration Statement or the Final Prospectus or to be filed as an exhibit

thereto, which is not described or filed as required (and the Preliminary Prospectus that is included in the Disclosure Package contains in all material respects the same description of the foregoing matters contained in the Final Prospectus). The Indenture, the Securities, the new Replacement Capital Covenant entered into by the Company for the initial benefit of the holders of the Securities (the “New Replacement Capital Covenant”), and the amendment of the Replacement Capital Covenant, dated as of December 1, 2006 (the “Existing RCC”), conform in all material respects to the descriptions thereof contained in the Registration Statement, the Disclosure Package and the Final Prospectus.

(k) The Indenture. The Indenture has been duly authorized by the Company, and when the Supplemental Indenture has been duly executed and delivered in accordance with its terms by each of the parties thereto, the Indenture will constitute a valid and legally binding agreement of the Company enforceable against the Company in accordance with its terms, except as enforceability may be limited by applicable bankruptcy, insolvency or similar laws affecting the enforcement of creditors’ rights generally or by equitable principles relating to enforceability (collectively, the “Enforceability Exceptions”).

(l) The Securities. The Securities have been duly authorized by the Company and, when duly executed, authenticated, issued and delivered as provided in the Indenture and paid for as provided herein, will be duly and validly issued and outstanding and will constitute valid and legally binding obligations of the Company entitled to the benefits of the Indenture.

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

(n) Investment Company Act. The Company is not and, after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described in the Disclosure Package and the Final Prospectus, will not be an “investment company” as defined in the Investment Company Act of 1940, as amended.

(o) No Consents Required. No consent, approval, authorization, filing with or order of any court or governmental agency or body is required to be obtained by the Company or any of its subsidiaries in connection with the transactions contemplated herein, including the amendment of the Existing RCC, except such as have been obtained under the Act and the Trust Indenture Act and such as may be required under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Securities by the Underwriters in the manner contemplated in this Agreement, the Disclosure Package and Final Prospectus.

(p) No Conflicts. Neither the execution and delivery of the Supplemental Indenture, the issue and sale of the Securities nor the consummation of any other of the transactions herein contemplated nor the fulfillment of the terms hereof will conflict with, result in a breach or violation of, or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of the Covered Subsidiaries pursuant to, (i) the charter or by-laws of the Company or any of the Covered Subsidiaries, (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which the Company or any of the Covered Subsidiaries is a party or bound or to which its or their property is subject, or (iii) any statute,

law, rule, regulation, judgment, order or decree applicable to the Company or any of its Covered Subsidiaries of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or any of the Covered Subsidiaries or any of its or their properties, except, in the case of clauses (ii) and (iii) above, for any such conflict, breach, violation or default that would not, individually or in the aggregate, have a Material Adverse Effect.

(q) No Registration Rights. No holders of securities of the Company have rights to the registration of such securities under the Registration Statement.

(r) Financial Statements. The consolidated historical financial statements and schedules of the Company and its consolidated subsidiaries, and the financial statements of American Transmission Company LLC (“ATC”) included in the Preliminary Prospectus, the Final Prospectus and the Registration Statement present fairly the financial condition, results of operations and cash flows of the Company and ATC, respectively, as of the dates and for the periods indicated, comply as to form with the applicable accounting requirements of the Act and have been prepared in conformity with generally accepted accounting principles applied on a consistent basis throughout the periods involved (except as otherwise noted therein). The selected financial data set forth under the caption “Summary Consolidated Financial Information” and “Capitalization” in the Preliminary Prospectus, the Prospectus and Registration Statement fairly present, on the basis stated in the Preliminary Prospectus, the Prospectus and the Registration Statement, the information included therein.

(s) Legal Proceedings. Except as described in the Registration Statement, the Disclosure Package and the Final Prospectus, there is no pending action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator to which the Company or any of its subsidiaries is or may be a party or to which any property of the Company or any of its subsidiaries is or may be the subject that, individually or in the aggregate, if determined adversely to the Company or any of its subsidiaries, could reasonably be expected to have a Material Adverse Effect or a material adverse effect on the performance of this Agreement or the consummation of any of the transactions contemplated thereby; no such actions, suits or proceedings are, to the best knowledge of the Company, threatened or contemplated by any governmental or regulatory authority or threatened by others; and there are no current or pending actions, suits or proceedings of a character that are required under the Act to be disclosed in the Registration Statement, the Disclosure Package and the Final Prospectus that are not adequately disclosed.

(t) Title to Real Property. The Company and its subsidiaries have good and marketable title in fee simple to, or have valid rights to lease or otherwise use, all items of real property that are material to the respective businesses of the Company and its subsidiaries, in each case free and clear of all liens, encumbrances, claims and defects and imperfections of title, except as otherwise disclosed in the Registration Statement, the Disclosure Package and the Final Prospectus and for those that (i) do not materially interfere with the use made and proposed to be made of such property by the Company and its subsidiaries or (ii) could not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.

(u) No Violation or Default. Neither the Company nor any of the Covered Subsidiaries is (i) in violation of its charter or by-laws or similar organizational documents; (ii) in default, and no event has occurred that, with notice or lapse of time or both, would constitute such a default, in the due performance or observance of any term, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of the Covered Subsidiaries is a party or by which the Company or any of the Covered Subsidiaries is bound or to which any of the property or assets of the Company or any of the Covered Subsidiaries is subject; or (iii) except as set forth in the Registration Statement, the Disclosure Package and the Final Prospectus, in violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory body, administrative agency or other authority having jurisdiction over the Company or such Covered Subsidiary or any of its property or assets, except, in the case of clauses (ii) and (iii) above, for any such default or violation that would not, individually or in the aggregate, have a Material Adverse Effect.

(v) Independent Accountants. Deloitte & Touche LLP, who have certified certain financial statements of the Company and its consolidated subsidiaries and of ATC and delivered their reports with respect to the audited consolidated financial statements and schedules of the Company and its consolidated subsidiaries and the audited financial statements of ATC included in the Disclosure Package and Final Prospectus is an independent registered public accounting firm with respect to the Company and its subsidiaries and ATC within the applicable rules and regulations adopted by the Commission and the Public Company Accounting Oversight Board (United States) and as required by the Act.

(w) Taxes. The Company and its subsidiaries have paid all material federal, state, local and foreign taxes, other than taxes that are being disputed in good faith by the Company or any of its subsidiaries, and have filed all material tax returns required to be paid or filed through the date hereof; and except as otherwise disclosed in the Registration Statement, the Disclosure Package and the Final Prospectus, there is no tax deficiency that has been, or could reasonably be expected to be, asserted against the Company or any of its subsidiaries or any of their respective properties or assets that could reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.

(x) No Labor Disputes. No labor disturbance by or dispute with employees of the Company or any of its subsidiaries exists or, to the best knowledge of the Company, is contemplated or threatened, except as disclosed in the Registration Statement, the Disclosure Package and the Final Prospectus, except for any such disturbance or dispute that would not, individually or in the aggregate, have a Material Adverse Effect.

(y) Insurance. The Company and each of its subsidiaries are insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as are prudent and customary in the businesses in which they are engaged; all policies of insurance insuring the Company or any of its subsidiaries or their respective businesses, assets, employees, officers and directors are in full force and effect; the Company and its subsidiaries are in compliance with the terms of such policies and instruments in all material respects; and there are no claims by the Company or any of its subsidiaries under any such policy or instrument as to which any insurance company is denying liability or defending under a

reservation of rights clause, except for such claims which, if successfully denied, would not have a Material Adverse Effect; and neither the Company nor any such subsidiary has any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business at a cost that would not have a Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(z) No Restrictions on Dividends or Distributions. Except as otherwise disclosed in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto), no Covered Subsidiary is currently prohibited, directly or indirectly, from paying any dividends to the Company, from making any other distribution on such Covered Subsidiary’s capital stock, from repaying to the Company any loans or advances to such Covered Subsidiary from the Company or from transferring any of such Covered Subsidiary’s properties or assets to the Company or any other subsidiary of the Company.

(aa) Licenses and Permits. The Company and its subsidiaries possess all licenses, certificates, permits and other authorizations issued by, and have made all declarations and filings with, the appropriate federal, state, local or foreign governmental or regulatory authorities that are necessary for the ownership or lease of their respective properties or the conduct of their respective businesses as described in the Registration Statement, the Disclosure Package and the Final Prospectus, except where the failure to possess or make the same would not, individually or in the aggregate, have a Material Adverse Effect; and except as described in the Registration Statement, the Disclosure Package and the Final Prospectus, neither the Company nor any of its subsidiaries has received notice of any revocation or modification of any such license, certificate, permit or authorization or has any reason to believe that any such license, certificate, permit or authorization will not be renewed in the ordinary course, except where the revocation, modification or non-renewal of the same would not, individually or in the aggregate, have a Material Adverse Effect.

(bb) Internal Accounting Controls. The Company and its subsidiaries maintain systems of “internal control over financial reporting” (as defined in Rule 13a-15(f) of the Exchange Act) that comply with the requirements of the Exchange Act and have been designed by, or under the supervision of, their respective principal executive and principal financial officers, or persons performing similar functions, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles, including, but not limited to 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. Except as disclosed in the Disclosure Package and the Final Prospectus, since the end of the Company’s most recent audited fiscal year, there have been (i) no material weaknesses in the Company’s internal control over financial reporting (whether or nor remediated), and (ii) no change in the Company’s

internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

(cc) Disclosure Controls. The Company and its subsidiaries maintain an effective system of “disclosure controls and procedures” (as defined in Rule 13a-15(e) of the Exchange Act) that is designed to ensure that information required to be disclosed by the Company in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms, including controls and procedures designed to ensure that such information is accumulated and communicated to the Company’s management as appropriate to allow timely decisions regarding required disclosure. The Company and its subsidiaries have carried out evaluations of the effectiveness of their disclosure controls and procedures as required by Rule 13a-15 of the Exchange Act.

(dd) No Stabilization. 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 sale or resale of the Securities.

(ee) Compliance with Environmental Laws. The Company and its subsidiaries (i) are in compliance with any and all applicable federal, state, local and foreign laws, rules, regulations, requirements, decisions and orders relating to the protection of human health or safety, the environment, natural resources, hazardous or toxic substances or wastes, pollutants or contaminants (collectively, “Environmental Laws”); (ii) have received and are in compliance with all permits, licenses, certificates or other authorizations or approvals required of them under applicable Environmental Laws to conduct their respective businesses; and (z) have not received notice of any actual or potential liability under or relating to any Environmental Laws, including for the investigation or remediation of any disposal or release of hazardous or toxic substances or wastes, pollutants or contaminants, except as in any such case as disclosed in the Registration Statement, the Disclosure Package and the Final Prospectus and for any such failure to comply, or failure to receive required permits, licenses or approvals, or liability, as would not, individually or in the aggregate, have a Material Adverse Effect. Except as set forth in the Disclosure Package and the Final Prospectus, neither the Company nor any of its subsidiaries has been named as a “potentially responsible party” under the Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended, except in such instances which would not, individually or in the aggregate, have a Material Adverse Effect.

(ff) Periodic Review of the Effect of Environmental Laws on the Company. In the ordinary course of its business, the Company periodically reviews the effect of Environmental Laws on the business, operations and properties of the Company and its subsidiaries, in the course of which it identifies and evaluates associated costs and liabilities (including, without limitation, any capital or operating expenditures required for clean-up, 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 review, the Company has reasonably concluded that such associated costs and liabilities would not, singly or in the aggregate, have a Material Adverse

Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto)

(gg) Compliance with ERISA. (i) Each employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), that is maintained, administered or contributed to by the Company or any of its affiliates for employees or former employees of the Company and its affiliates (each such plan, a “Plan”) has been maintained in compliance in all material respects with its terms and the requirements of any applicable statutes, orders, rules and regulations, including but not limited to ERISA and the Internal Revenue Code of 1986, as amended (the “Code”); (ii) no prohibited transaction, within the meaning of Section 406 of ERISA or Section 4975 of the Code, has occurred with respect to any such Plan excluding transactions effected pursuant to a statutory or administrative exemption; and (iii) for each such Plan that is subject to the funding rules of Section 412 of the Code or Section 302 of ERISA, no “accumulated funding deficiency” as defined in Section 412 of the Code has been incurred, whether or not waived. Except as set forth in the Disclosure Package and the Final Prospectus, there has been (i) no material increase in the aggregate amount of contributions required to be made to all Plans in the current fiscal year of the Company and its subsidiaries compared to the amount of such contributions made in the most recently completed fiscal year of the Company and its subsidiaries; and (ii) no material increase in the “accumulated post-retirement benefit obligations” (within the meaning of Statement of Financial Accounting Standards 106) of the Company and its subsidiaries compared to the amount of such obligations in the most recently completed fiscal year of the Company and its subsidiaries.

(hh) Forward-Looking Statements. No forward-looking statement (within the meaning of Section 27A of the Act and Section 21E of the Exchange Act) contained in the Registration Statement, the Disclosure Package and the Final Prospectus has been made or reaffirmed without a reasonable basis or has been disclosed other than in good faith.

(ii) ▇▇▇▇▇▇▇▇-▇▇▇▇▇ Act. There is and has been no failure on the part of the Company or any of the Company’s directors or officers, in their capacities as such, to comply with any provision of the ▇▇▇▇▇▇▇▇-▇▇▇▇▇ Act of 2002 and the rules and regulations promulgated in connection therewith (the “▇▇▇▇▇▇▇▇-▇▇▇▇▇ Act”), including Section 402 relating to loans and Sections 302 and 906 relating to certifications.

(jj) Foreign Corrupt Practices Act. Neither the Company nor any of its subsidiaries nor, to the best knowledge of the Company, any director, officer, agent, employee or other person associated with or acting on behalf of the Company or any of its subsidiaries has (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds; (iii) violated or is in violation of any provision of the Foreign Corrupt Practices Act of 1977; or (iv) made any bribe, rebate, payoff, influence payment, kickback or other unlawful payment.

(kk) Lending Relationships. Except as disclosed in the Registration Statement, the Disclosure Package and the Final Prospectus, the Company (i) does not have any material lending or other relationship with any bank or lending affiliate of Citigroup Global Markets

Holdings Inc. or of any of the Underwriters 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 Citigroup Global Markets Holdings Inc. or of any of the Underwriters.

(ll) No Immunity from Jurisdiction. Neither the Company nor any of its subsidiaries nor any of its or their properties or assets has any immunity from the jurisdiction of any court or from any legal process (whether through service or notice, attachment prior to judgment, attachment in aid of execution or otherwise) under the laws of the United States of America or any state or political subdivision thereof.

Any certificate signed by any officer of the Company and delivered to the Representatives or counsel for the Underwriters in connection with the offering of the Securities shall be deemed a representation and warranty by the Company, as to matters covered thereby, to each Underwriter.

2. Purchase and Sale. Subject to the terms and conditions and in reliance upon the representations and warranties herein set forth, the Company agrees to sell to each Underwriter, and each Underwriter agrees, severally and not jointly, to purchase from the Company, at the purchase price set forth in Schedule I hereto the principal amount of the Securities set forth opposite such Underwriter’s name in Schedule II hereto.

3. Delivery and Payment. Delivery of and payment for the Securities shall be made on the date and at the time specified in Schedule I hereto or at such time on such later date not more than three Business Days after the foregoing date as the Representatives shall designate, which date and time may be postponed by agreement between the Representatives and the Company or as provided in Section 9 hereof (such date and time of delivery and payment for the Securities being herein called the “Closing Date”). 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 purchase price thereof to or upon the order of the Company by wire transfer payable in same-day funds to an account specified by the Company. Delivery of the Securities shall be made through the facilities of The Depository Trust Company unless the Representatives shall otherwise instruct. One or more global notes representing the Securities shall be registered in such names and in such denominations as Citigroup Global Markets Inc. may request not less than two Business Days in advance of the Closing Date.

The Company agrees to have such global note or global notes available for inspection by the Representative not later than 1:00 PM, New York City time, on the Business Day prior to the Closing Date.

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 Final Prospectus.

5. Agreements. The Company agrees with the several Underwriters that:

(a) Prior to the termination of the offering of the Securities, the Company will not file any amendment of the Registration Statement or supplement (including the Final Prospectus or any Preliminary Prospectus) to the Base Prospectus unless the Company has

furnished you a copy for your review prior to filing and will not file any such proposed amendment or supplement to which you reasonably object. The Company will cause the Final Prospectus, properly completed, and any supplement thereto to be filed in a form approved by the Representatives with the Commission pursuant to the applicable paragraph of Rule 424(b) within the time period prescribed and will provide evidence satisfactory to the Representatives of such timely filing. The Company will promptly advise the Representatives (i) when the Final Prospectus, and any supplement thereto, shall have been filed (if required) with the Commission pursuant to Rule 424(b), (ii) when, prior to termination of the offering of the Securities, any amendment to the Registration Statement shall have been filed or become effective, (iii) of any request by the Commission or its staff for any amendment of the Registration Statement, or any Rule 462(b) Registration Statement, or for any supplement to the Final Prospectus or for any additional information, or (iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any notice objecting to its use or the institution or threatening of any proceeding for that purpose. The Company will use its best efforts to prevent the issuance of any such stop order or the occurrence of any such suspension or objection to the use of the Registration Statement and, upon such issuance, occurrence or notice of objection, to obtain as soon as possible the withdrawal of such stop order or relief from such occurrence or objection, including, if necessary, by filing an amendment to the Registration Statement or a new registration statement and using its best efforts to have such amendment or new registration statement declared effective as soon as practicable.

(b) The Company will prepare a final term sheet, containing solely a description of final terms of the Securities and the offering thereof, in the form approved by you and attached as Schedule IV hereto and to file such term sheet pursuant to Rule 433(d) within the time required by such Rule.

(c) If, at any time prior to the filing of the Final Prospectus pursuant to Rule 424(b), any event occurs as a result of which the Disclosure Package would include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein in the light of the circumstances under which they were made or the circumstances then prevailing not misleading, the Company will (i) notify promptly the Representatives so that any use of the Disclosure Package may cease until it is amended or supplemented; (ii) amend or supplement the Disclosure Package to correct such statement or omission; and (iii) supply any amendment or supplement to you in such quantities as you may reasonably request.

(d) If, at any time when a prospectus relating to the Securities is required to be delivered under the Act (including in circumstances where such requirement may be satisfied pursuant to Rule 172), any event occurs as a result of which the Final Prospectus as then supplemented would include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein in the light of the circumstances under which they were made at such time not misleading, or if it shall be necessary to amend the Registration Statement, file a new registration statement or supplement the Final Prospectus to comply with the Act or the Exchange Act or the respective rules thereunder, including in connection with use or delivery of the Final Prospectus, the Company promptly will (i) notify the Representatives of any such event, (ii) prepare and file with the Commission, subject to the second sentence of paragraph (a) of this Section 5, an amendment or supplement or new

registration statement which will correct such statement or omission or effect such compliance, (iii) use its best efforts to have any amendment to the Registration Statement or new registration statement declared effective as soon as practicable in order to avoid any disruption in use of the Final Prospectus and (iv) supply any supplemented Final Prospectus to you in such quantities as you may reasonably request.

(e) As soon as practicable, the Company will make generally available to its security holders and to the Representatives an earnings statement or statements of the Company and its subsidiaries which will satisfy the provisions of Section 11(a) of the Act and Rule 158.

(f) The Company will furnish to the Representatives and counsel for the Underwriters, without charge, signed copies of the Registration Statement (including exhibits thereto) and to each other Underwriter a copy of the Registration Statement (without exhibits thereto) and, so long as delivery of a prospectus by an Underwriter or dealer may be required by the Act (including in circumstances where such requirement may be satisfied pursuant to Rule 172), as many copies of each Preliminary Prospectus, the Final Prospectus and each Issuer Free Writing Prospectus and any supplement thereto as the Representatives may reasonably request. The Company will pay the expenses of printing or other production of all documents relating to the offering.

(g) The Company agrees that, unless it has or shall have obtained the prior written consent of the Representatives, and each Underwriter, severally and not jointly, agrees with the Company that, unless it has or shall have obtained, as the case may be, the prior written consent of the Company, it has not made and will not make any offer relating to the Securities that would constitute an Issuer Free Writing Prospectus or that would otherwise constitute a “free writing prospectus” (as defined in Rule 405) required to be filed by the Company with the Commission or retained by the Company under Rule 433, other than a free writing prospectus containing the information contained in the final term sheet prepared and filed pursuant to Section 5(b) hereto; provided that the prior written consent of the parties hereto shall be deemed to have been given in respect of the Free Writing Prospectuses included in Schedule III hereto and each electronic road show, if any. Any such free writing prospectus consented to by the Representatives or the Company is hereinafter referred to as a “Permitted Free Writing Prospectus.” The Company agrees that (x) it has treated and will treat, as the case may be, each Permitted Free Writing Prospectus as an Issuer Free Writing Prospectus and (y) it has complied and will comply, as the case may be, with the requirements of Rules 164 and 433 applicable to any Permitted Free Writing Prospectus, including in respect of timely filing with the Commission, legending and record keeping.

(h) The Company will not, without the prior written consent of Citigroup Global Markets Inc., offer, sell, contract to sell, 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 Company or any affiliate of the Company or any person in privity with the Company or any affiliate of the Company), directly or indirectly, including the filing (or participation in the filing) of a registration statement with the 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 Exchange Act, any debt securities issued or guaranteed by the Company and having a term of more than one year (other than the Securities) or publicly announce an intention to effect any such transaction, until the Business Day set forth on Schedule I hereto.

(i) The Company will not take, 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 sale or resale of the Securities.

(j) The Company will pay the costs and expenses relating to the following matters: (i) the preparation, printing or reproduction and filing with the Commission of the Registration Statement (including financial statements and exhibits thereto), each Preliminary Prospectus, the Final Prospectus and each Issuer Free Writing Prospectus, and each amendment or supplement to any of them; (ii) the printing (or reproduction) and delivery (including postage, air freight charges and charges for counting and packaging) of such copies of the Registration Statement, each Preliminary Prospectus, the Final Prospectus and each Issuer Free Writing Prospectus, and all amendments or supplements to any of them, as may, in each case, be reasonably requested for use in connection with the offering and sale of the Securities; (iii) the preparation, printing, authentication, issuance and delivery of certificates for the Securities, including any stamp or transfer taxes in connection with the original issuance and sale of the Securities; (iv) the printing (or reproduction) and delivery of this Agreement and all other agreements or documents printed (or reproduced) and delivered in connection with the offering of the Securities; (v) any filings required to be made with the Financial Industry Regulatory Authority (including filing fees and the reasonable fees and expenses of counsel to the Underwriters relating to the filings), (vi) the transportation and other expenses incurred by or on behalf of Company representatives in connection with presentations to prospective purchasers of the Securities; (vii) the fees and expenses of the Company’s accountants and the fees and expenses of counsel (including local and special counsel) for the Company; and (viii) all other costs and expenses incident to the performance by the Company of its obligations hereunder.

6. Conditions to the Obligations of the Underwriters. The obligations of the Underwriters to purchase the Securities shall be subject to the accuracy of the representations and warranties on the part of the Company contained herein as of the Execution Time and the Closing Date, to the accuracy of the statements of the Company made in any certificates pursuant to the provisions hereof, to the performance by the Company of its obligations hereunder and to the following additional conditions:

(a) The Final Prospectus, and any supplement thereto, have been filed in the manner and within the time period required by Rule 424(b); the final term sheet contemplated by Section 5(b) hereto, and any other material required to be filed by the Company pursuant to Rule 433(d) under the Act, shall have been filed with the Commission within the applicable time periods prescribed for such filings by Rule 433; and no stop order suspending the effectiveness of the Registration Statement or any notice objecting to its use shall have been issued and no proceedings for that purpose shall have been instituted or threatened.

(b) The Company shall have requested and caused ▇▇▇▇▇ & ▇▇▇▇▇▇▇ LLP, counsel for the Company, to have furnished to the Representatives their opinion, dated the Closing Date and addressed to the Representatives, to the effect that:

(i) The Registration Statement has become effective under the Act; any required filing of the Base Prospectus, any Preliminary Prospectus and the Final Prospectus, and any supplements thereto, pursuant to Rule 424(b) has been made in the manner and within the time period required by Rule 424(b); to the knowledge of such counsel, no stop order suspending the effectiveness of the Registration Statement or any notice objecting to its use has been issued, no proceedings for that purpose have been instituted or threatened, and the Registration Statement and the Final Prospectus (other than the financial statements and other financial and statistical information contained or incorporated by reference therein, as to which such counsel need express no opinion) comply as to form in all material respects with the applicable requirements of the Act, the Exchange Act and the Trust Indenture Act and the respective rules thereunder;

(ii) The Company has been duly organized and is validly existing as a corporation under the laws of the State of Wisconsin with power and authority (corporate and other) to own, lease and operate its properties and conduct its business as described in the Registration Statement, the Disclosure Package and the Final Prospectus; based solely on a certificate of the Department of Financial Institutions of the State of Wisconsin, the Company has not filed articles of dissolution with the Department of Financial Institutions of the State of Wisconsin, and the Department of Financial Institutions of the State of Wisconsin has not commenced proceedings to dissolve such corporation administratively pursuant to the provisions of the Wisconsin Business Corporation Law and has made no determination that grounds exist for such action; the Company is duly qualified as a foreign corporation to transact business and is in good standing in each jurisdiction in which its ownership or lease of properties or the conduct of its business requires such qualification, except where the failure to so qualify and be in good standing would not, individually or in the aggregate, have a Material Adverse Effect;

(iii) Each Covered Subsidiary is validly existing under the laws of the jurisdiction of its incorporation or organization and has corporate or limited liability company power, as applicable, and authority to own, lease and operate its properties and conduct its business as described in the Registration Statement, the Disclosure Package and the Final Prospectus; based solely on a certificate of the Department of Financial Institutions of the State of Wisconsin, no Covered Subsidiary which is organized under the laws of the State of Wisconsin has filed articles of dissolution with the Department of Financial Institutions of the State of Wisconsin, and the Department of Financial Institutions of the State of Wisconsin has not commenced proceedings to dissolve any such Covered Subsidiary administratively pursuant to the provisions of the Wisconsin Business Corporation Law or Chapter 183 of the Wisconsin Statutes, as applicable, and has made no determination that grounds exist for such action;

(iv) All of the outstanding shares of capital stock or other equity interests of WPS, TEGE and PEC have been duly and validly authorized and issued, are fully paid

and non-assessable, except for WPS and TEGE as noted in counsel’s opinion regarding former Section 180.0622(2)(b) of the Wisconsin Business Corporation Law; and except for the preferred stock of WPS, all outstanding shares of capital stock of the Covered Subsidiaries are owned of record by the Company, either directly or through wholly owned subsidiaries.

(v) The Indenture has been duly authorized, executed and delivered by the Company and, assuming due execution and delivery thereof by the Trustee, constitutes a valid and legally binding agreement of the Company enforceable against the Company in accordance with its terms, subject to the Enforceability Exceptions. The Indenture has been duly qualified under the Trust Indenture Act;

(vi) The Securities have been duly authorized, executed and delivered by the Company and, when duly authenticated as provided in the Indenture and paid for by the Underwriters as provided in this Agreement, will be duly and validly issued and outstanding and will constitute valid and legally binding obligations of the Company entitled to the benefits of the Indenture;

(vii) To the best knowledge of such counsel following reasonable investigation (which investigation shall be detailed in the opinion and shall include appropriate searches of court dockets), there is no pending or threatened action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator to which the Company or any of its subsidiaries is or may be a party or to which any property of the Company or any of its subsidiaries is or may be subject, of a character that is required to be disclosed in the Registration Statement which is not adequately disclosed in each Preliminary Prospectus and the Final Prospectus;

(viii) The descriptions in the Registration Statement, the Disclosure Package and the Final Prospectus of (i) statutes, (ii) legal, governmental and regulatory proceedings relating to the Company, and (iii) contracts and other documents are accurate in all material respects; and the statements incorporated by reference in the Preliminary Prospectus and the Final Prospectus from Item 3 of Part I of the Company’s Annual Report on Form 10-K for the year ended 2009, to the extent that they constitute summaries of matters of law or regulation or legal conclusions, fairly summarize the matters described therein in all material respects. To the best knowledge of such counsel, there is no franchise, contract or other document of a character required to be described in the Registration Statement or the Final Prospectus or to be filed as an exhibit thereto, which is not described or filed as required. The Indenture, the Securities, the New Replacement Capital Covenant and the amendment of the Existing RCC conform in all material respects to the descriptions thereof contained in the Registration Statement, any Preliminary Prospectus and the Final Prospectus;

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

(x) The Company is not and, after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described in the Disclosure

Package and the Final Prospectus, will not be an “investment company” as defined in the Investment Company Act of 1940, as amended;

(xi) No consent, approval, authorization, filing with or order of any court or governmental agency or body is required to be obtained by the Company in connection with the transactions contemplated herein, including the amendment of the Existing RCC, except such as have been obtained under the Act and the Trust Indenture Act and such as may be required under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Securities by the Underwriters in the manner contemplated in this Agreement, the Disclosure Package and Final Prospectus;

(xii) Neither the execution and delivery of the Supplemental Indenture, the issue and sale of the Securities nor the consummation of any other of the transactions herein contemplated nor the fulfillment of the terms hereof will conflict with, result in a breach or violation of, or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of the Covered Subsidiaries pursuant to, (i) the charter or by-laws of the Company or any of the Covered Subsidiaries, (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument filed as an exhibit to the Company’s most recent Annual Report on Form 10-K or any other indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which the Company or any of WPS, PGL, TEGE and PEC (the “Principal Subsidiaries”) is a party or bound or to which its or their property is subject, or (iii) any statute, law, rule, or regulation or, to the best knowledge of such counsel following reasonable investigation, including an inquiry of the Company and those lawyers at ▇▇▇▇▇ & Lardner LLP who have provided legal services to the Company and its subsidiaries in the past two years, any judgment, order or decree applicable to the Company or any of the Principal Subsidiaries of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or any of the Principal Subsidiaries or any of its or their properties, except, in the case of clauses (ii) and (iii) above, for any such conflict, breach, violation or default that would not, individually or in the aggregate, have a Material Adverse Effect;

(xiii) To the best knowledge of such counsel, no holders of securities of the Company have rights to the registration of such securities under the Registration Statement.

(xiv) The Company and its subsidiaries have statutory authority, franchises, permits, easements and consents adequate to conduct the businesses in which they are respectively engaged without legal restrictions that would materially affect their ability to so conduct such business.

Such counsel shall also state that they have participated in conferences with representatives of the Company and with representatives of its independent accountants and counsel at which conferences the contents of the Registration Statement, the Disclosure Package and the Final Prospectus and any amendment and supplement thereto and related matters were discussed and,

although such counsel assumes no responsibility for the accuracy, completeness or fairness of the Registration Statement, the Disclosure Package, the Final Prospectus and any amendment or supplement thereto (except as expressly provided above), nothing has come to the attention of such counsel to cause such counsel to believe that (1) on the Effective Date the Registration Statement contained any untrue statement of a material fact or omitted to state any material fact required to be stated therein or necessary to make the statements therein not misleading or that the Final Prospectus as of its date and on the Closing Date included or includes any untrue statement of a material fact or omitted 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 (in each case, other than the financial statements and other financial information contained or incorporated by reference therein, as to which such counsel need express no belief); and (2) the Disclosure Package, as amended or supplemented at the Execution Time, contained any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading (other than the financial statements and other financial information contained or incorporated by reference therein, as to which such counsel need express no belief).

In rendering such opinion, such counsel may rely (A) as to matters involving the application of laws of any jurisdiction other than the State of Wisconsin or the Federal laws of the United States, to the extent they deem proper and specified in such opinion, upon the opinion of other counsel of good standing whom they believe to be reliable and who are satisfactory to counsel for the Underwriters, and (B) as to matters of fact, to the extent they deem proper, on certificates of responsible officers of the Company and public officials. References to the Final Prospectus in this paragraph (b) shall also include any supplements thereto at the Closing Date.

(c) The Representatives shall have received from ▇▇▇▇▇▇ ▇▇▇▇▇▇ LLP, counsel for the Underwriters, such opinion or opinions, dated the Closing Date and addressed to the Representatives, with respect to the issuance and sale of the Securities, the Indenture, the Registration Statement, the Disclosure Package, the Final Prospectus (together with any supplement thereto) and other related matters as the Representatives may reasonably require, and the Company shall have furnished to such counsel such documents as they request for the purpose of enabling them to pass upon such matters.

(d) The Company shall have furnished to the Representatives a certificate of the Company, signed by the Chairman of the Board or the President and the principal financial or accounting officer of the Company, dated the Closing Date, to the effect that the signers of such certificate have carefully examined the Registration Statement, the Disclosure Package, the Final Prospectus and any supplements or amendments thereto, as well as each electronic road show, if any, used in connection with the offering of the Securities, and this Agreement and that:

(i) the representations and warranties of the Company in this Agreement are true and correct on and as of the Closing Date with the same effect as if made on the Closing Date and the Company has complied with all the agreements and satisfied all the conditions on its part to be performed or satisfied at or prior to the Closing Date;

(ii) no stop order suspending the effectiveness of the Registration Statement or any notice objecting to its use has been issued and no proceedings for that purpose have been instituted or, to the Company’s knowledge, threatened; and

(iii) since the date of the most recent financial statements included in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto), there has been no Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(e) The Company shall have requested and caused Deloitte & Touche LLP to have furnished to the Representatives, at the Execution Time and at the Closing Date, letters, (which may refer to letters previously delivered to one or more of the Representatives), dated respectively as of the Execution Time and as of the Closing Date, in form and substance satisfactory to the Representatives, confirming that they are independent accountants within the meaning of the Act and the Exchange Act and the respective applicable rules and regulations adopted by the Commission thereunder and that they have performed a review of the unaudited interim financial information of the Company and its subsidiaries for the nine-month period ended September 30, 2010, and as of September 30, 2010 in accordance with the Public Company Accounting Oversight Board Interim Auditing Standard 722, and stating in effect that:

(i) in their opinion the audited financial statements and financial statement schedules of the Company and its subsidiaries and of ATC included or incorporated by reference in the Registration Statement, the Preliminary Prospectus and the Final Prospectus and reported on by them comply as to form with the applicable accounting requirements of the Act and the Exchange Act and the related rules and regulations adopted by the Commission;

(ii) on the basis of a reading of the latest unaudited financial statements made available by the Company and its subsidiaries; their limited review, in accordance with standards established under the Public Company Accounting Oversight Board Interim Auditing Standard 722, of the unaudited interim financial information for the nine-month period ended September 30, 2010 and as at September 30, 2010, carrying out certain specified procedures (but not an examination in accordance with generally accepted auditing standards) which would not necessarily reveal matters of significance with respect to the comments set forth in such letter; a reading of the minutes of the meetings of the stockholders, directors and audit committee of the Company and the Subsidiaries; and inquiries of certain officials of the Company who have responsibility for financial and accounting matters of the Company and its subsidiaries as to transactions and events subsequent to December 31, 2009, nothing came to their attention which caused them to believe that:

(1) any unaudited financial statements included or incorporated by reference in the Registration Statement, the Preliminary Prospectus and

the Final Prospectus do not comply as to form with applicable accounting requirements of the Act and with the related rules and regulations adopted by the Commission with respect to financial statements included or incorporated by reference in quarterly reports on Form 10-Q under the Exchange Act; and said unaudited financial statements are not in conformity with generally accepted accounting principles applied on a basis substantially consistent with that of the audited financial statements included or incorporated by reference in the Registration Statement, the Preliminary Prospectus and the Final Prospectus;

(2) with respect to the period subsequent to September 30, 2010, there were, at a specified date not more than five days prior to the date of the letter, any change in the common stock, increase in long-term debt, or decreases in current assets or total common shareholders’ equity of the Company and its consolidated subsidiaries as compared with the amounts shown on the September 30, 2010 consolidated balance sheet included or incorporated by reference in the Registration Statement, the Preliminary Prospectus and the Final Prospectus, or for the period from October 1, 2010 to such specified date there were any decreases, as compared with the corresponding period in the preceding year, in total revenues or in earnings (loss) per common share (basic), except in all instances for changes or decreases set forth in such letter, in which case the letter shall be accompanied by an explanation by the Company as to the significance thereof unless said explanation is not deemed necessary by the Representatives; and

(3) the information included or incorporated by reference in the Registration Statement, the Preliminary Prospectus and Final Prospectus in response to Regulation S-K, Item 301 (Selected Financial Data), Item 302 (Supplementary Financial Information), and Item 503(d) (Ratio of Earnings to Fixed Charges) is not in conformity with the applicable disclosure requirements of Regulation S-K;

(iii) they have performed certain other specified procedures as a result of which they determined that certain information of an accounting, financial or statistical nature (which is limited to accounting, financial or statistical information derived from the general accounting records of the Company and its subsidiaries) set forth in the Registration Statement, the Preliminary Prospectus and the Final Prospectus and in Exhibit 12 to the Registration Statement, including the information set forth under the captions “Summary Consolidated Financial Information” and “Capitalization” in the Preliminary Prospectus and the Final Prospectus, the information included or incorporated by reference in Items 1, 2, 6, and 7 of the Company’s Annual Report on Form 10-K, incorporated by reference in the Registration Statement, the Preliminary Prospectus and the Final Prospectus, and the information included in the “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included or incorporated by reference in the Company’s Quarterly Reports on Form 10-Q,

incorporated by reference in the Registration Statement, the Preliminary Prospectus and the Final Prospectus, agrees with the accounting records of the Company and its subsidiaries, excluding any questions of legal interpretation.

References to the Final Prospectus in this paragraph (e) include any supplement thereto at the date of the letter.

(f) Subsequent to the Execution Time or, if earlier, the dates as of which information is given in the Registration Statement (exclusive of any amendment thereof) and the Final Prospectus (exclusive of any amendment or supplement thereto), there shall not have been (i) any change or decrease specified in the letter or letters referred to in paragraph (e) of this Section 6 or (ii) any change, or any development involving a prospective change, in or affecting the condition (financial or otherwise), earnings, business or properties of the Company and its subsidiaries taken as a whole, whether or not arising from transactions in the ordinary course of business, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any amendment or supplement thereto) the effect of which, in any case referred to in clause (i) or (ii) above, is, in the judgment of the Representatives, so material and adverse as to make it impractical or inadvisable to proceed with the offering or delivery of the Securities as contemplated by the Registration Statement (exclusive of any amendment thereof), the Disclosure Package and the Final Prospectus (exclusive of any amendment or supplement thereto).

(g) Subsequent to the Execution Time, there shall not have been any decrease in the rating of any of the Company’s debt securities by any “nationally recognized statistical rating organization” (as defined for purposes of Rule 436(g) under the Act) or any notice given of any intended or potential decrease in any such rating or of a possible change in any such rating that does not indicate an improvement in such rating.

(h) Prior to the Closing Date, the Company shall have furnished to the Representatives such further information, certificates and documents as the Representatives may reasonably request.

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 in writing or by telephone or facsimile confirmed in writing.

The documents required to be delivered by this Section 6 on the Closing Date shall be delivered at the office of ▇▇▇▇▇ & ▇▇▇▇▇▇▇ LLP, counsel for the Company, at ▇▇▇ ▇▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇.

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 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 reasonable 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.

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 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 the Base Prospectus, any Preliminary Prospectus, the Final Prospectus, any Issuer Free Writing Prospectus or the information contained in the final term sheet required to be prepared and filed pursuant to Section 5(b) hereto, 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) 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, to the same extent as the foregoing indemnity from the Company to each Underwriter, but only with respect 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 acknowledges that the statements set forth in the Preliminary Prospectus and the Final Prospectus in the third paragraph under the heading “Underwriting” related to concessions and reallowances and in the fifth and sixth paragraphs under the heading “Underwriting” related to stabilization and syndicate covering transactions constitute the only information furnished in writing by or on behalf of the several Underwriters for inclusion in any Preliminary Prospectus, the Final Prospectus or any Issuer Free Writing Prospectus.

(c) 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) or (b) 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) or (b) 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 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; it being understood and agreed that the indemnifying party shall not, in connection with any proceeding or related proceeding in the same jurisdiction, be liable for the fees and expenses of more than one separate counsel (in addition to any local counsel) for all indemnified parties. 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 includes an unconditional release of each indemnified party from all liability arising out of such claim, action, suit or proceeding.

(d) 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 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 the same) (collectively “Losses”) to which the Company 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 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

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 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 shall be deemed to be equal to the total net proceeds from the offering (before deducting expenses) received by it, 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 Final 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 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 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 (d).

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 principal amount of Securities set forth opposite their names in Schedule II hereto bears to the aggregate principal amount of Securities set forth opposite the names of all the remaining Underwriters) the Securities which the defaulting Underwriter or Underwriters agreed but failed to purchase; provided, however, that in the event that the aggregate principal amount of Securities which the defaulting Underwriter or Underwriters agreed but failed to purchase shall exceed 10% of the aggregate principal amount of Securities set forth in Schedule II 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 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 Final 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 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 delivery and payment (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 any Preliminary Prospectus or the Final Prospectus (exclusive of any amendment or supplement thereto).

11. Representations and Indemnities to Survive. The respective agreements, representations, warranties, indemnities and other statements of the Company or its officers 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 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 (a) if sent to the Representatives, will be mailed, delivered or telefaxed to (i) Citigroup Global Markets Inc., General Counsel (fax no.: (▇▇▇) ▇▇▇-▇▇▇▇), and confirmed to Citigroup Global Markets Inc. at ▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇, ▇▇▇▇▇, Attention: General Counsel; (ii) Mitsubishi UFJ Securities (USA), Inc., Capital Markets Group (fax no.: (▇▇▇) ▇▇▇-▇▇▇▇) and confirmed to Mitsubishi UFJ Securities (USA), Inc. at ▇▇▇▇ ▇▇▇▇▇▇▇▇, ▇▇▇▇ ▇▇▇▇▇, ▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇ ▇▇▇▇▇, Attention: Capital Markets Group, and (iii) ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. Incorporated, Investment Banking Division (fax no.: (▇▇▇) ▇▇▇-▇▇▇▇ and confirmed to ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. Incorporated at ▇▇▇▇ ▇▇▇▇▇▇▇▇, ▇▇▇▇ ▇▇▇▇▇, ▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇ ▇▇▇▇▇, Attention: Investment Banking Division, or (b) if sent to the Company, will be mailed, delivered or telefaxed to Integrys Energy Group, Inc., Vice President and Treasurer (fax no.: (▇▇▇) ▇▇▇-▇▇▇▇) and confirmed to it at ▇▇▇ ▇▇▇▇▇ ▇▇▇▇▇ ▇▇▇▇▇▇, ▇.▇. ▇▇▇ ▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇, ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇, attention Vice President and Treasurer.

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. No fiduciary duty. The Company hereby acknowledges that (a) the purchase and sale of the Securities pursuant to this Agreement is an arm’s-length commercial transaction between the Company, on the one hand, and the Underwriters and any affiliate through which it may be acting, on the other, (b) the Underwriters are acting as principal and not as an agent or fiduciary of the Company and (c) the Company’s engagement of the Underwriters in connection with the offering and the process leading up to the offering is as independent

contractors and not in any other capacity. Furthermore, the Company agrees that it is solely responsible for making its own judgments in connection with the offering (irrespective of whether any of the Underwriters has advised or is currently advising the Company on related or other matters). The Company agrees that it will not claim that the Underwriters have rendered advisory services of any nature or respect, or owe an agency, fiduciary or similar duty to the Company, in connection with such transaction or the process leading thereto.

15. Integration. This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Underwriters, or any of them, with respect to the subject matter hereof.

16. 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.

17. Waiver of Jury Trial. The Company and the Underwriters each hereby irrevocably waive, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby.

18. 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.

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

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

“Act” shall mean the Securities Act of 1933, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Base Prospectus” shall mean the base prospectus referred to in paragraph 1(a) above contained in the Registration Statement at the Execution Time.

“Business Day” shall mean any day other than a Saturday, a Sunday or a legal holiday or a day on which banking institutions or trust companies are authorized or obligated by law to close in New York City or Chicago, Illinois.

“Commission” shall mean the Securities and Exchange Commission.

“Disclosure Package” shall mean (i) the Base Prospectus, (ii) the Preliminary Prospectus used most recently prior to the Execution Time, (iii) the Issuer Free Writing Prospectuses, if any, identified in Schedule III hereto, (iv) the final term sheet prepared and filed pursuant to Section 5(b) hereto, if any, and (v) any other Free Writing Prospectus that the parties hereto shall hereafter expressly agree in writing to treat as part of the Disclosure Package.

“Effective Date” shall mean each date and time that the Registration Statement and any post-effective amendment or amendments thereto became or becomes effective.

“Exchange Act” shall mean the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Execution Time” shall mean the date and time that this Agreement is executed and delivered by the parties hereto.

“Final Prospectus” shall mean the prospectus supplement relating to the Securities that is first filed pursuant to Rule 424(b) after the Execution Time, together with the Base Prospectus.

“Free Writing Prospectus” shall mean a free writing prospectus, as defined in Rule 405.

“Issuer Free Writing Prospectus” shall mean an issuer free writing prospectus, as defined in Rule 433.

“Preliminary Prospectus” shall mean any preliminary prospectus supplement to the Base Prospectus referred to in paragraph 1(a) above which is used prior to the filing of the Final Prospectus, together with the Base Prospectus.

“Registration Statement” shall mean the registration statement referred to in paragraph 1(a) above, including exhibits and financial statements and any prospectus supplement relating to the Securities that is filed with the Commission pursuant to Rule 424(b) and deemed part of such registration statement pursuant to Rule 430B, as amended on each Effective Date and, in the event any post-effective amendment thereto becomes effective prior to the Closing Date, shall also mean such registration statement as so amended.

“Rule 158”, “Rule 163”, “Rule 164”, “Rule 172”, “Rule 405”, “Rule 415”, “Rule 424”, “Rule 430B” and “Rule 433” refer to such rules under the Act.

“Trust Indenture Act” shall mean the Trust Indenture Act of 1939, as amended and the rules and regulations of the Commission promulgated thereunder.

“Well-Known Seasoned Issuer” shall mean a well-known seasoned issuer, as defined in Rule 405.

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 and the several Underwriters.

Very truly yours,

INTEGRYS ENERGY GROUP, INC.

By: /s/ ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇

Name: ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇

Title: Vice President and Treasurer

The foregoing Agreement is

hereby confirmed and accepted

as of the date specified in

Schedule I hereto.

CITIGROUP GLOBAL MARKETS INC.

MITSUBISHI UFJ SECURITIES (USA), INC.

▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & CO. INCORPORATED

By CITIGROUP GLOBAL MARKETS INC.

By: /s/ ▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇

Name: ▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇

Title: Managing Director

For themselves and the other

several Underwriters, if any,

named in Schedule II to the

foregoing Agreement.

SCHEDULE I

Underwriting Agreement dated November 9, 2010

Registration Statement No. 333-158218

Representatives: Citigroup Global Markets Inc.,

Mitsubishi UFJ Securities (USA), Inc., and

▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. Incorporated

Title, Purchase Price and Description of Securities:

Title: 4.170% Senior Notes Due November 1, 2020

Principal amount: $250,000,000

Purchase price, net of underwriting commission

(include accrued interest or amortization, if

any): $248,217,500

Sinking fund provisions: None

Redemption provisions: The Securities will be redeemable at the option of the Company, in whole at any time or in part from time to time, at a redemption price equal to the greater of (1) 100% of principal or (2) the sum of the present values of the remaining scheduled payments of principal and interest on the Securities which the Company redeems, discounted to the date of redemption on a semi-annual basis, assuming a 360-day year consisting of twelve 30-day months, at the Treasury Yield (as defined in the Final Prospectus and the Supplemental Indenture) plus 0.250 of one percent (0.250%), plus, in each case, accrued and unpaid interest to the date of redemption.

Other provisions: The Supplemental Indenture will provide that the holders of the Securities as of December 1, 2010, as holders of the then “covered debt” under the Existing RCC, will irrevocably consent to certain amendments to the Existing RCC, effective as of December 1, 2010, the date on which the Securities will become “covered debt” under the Existing RCC, as more fully described in the Preliminary Prospectus and Final Prospectus.

Closing Date, Time and Location: November 15, 2010 at 10:00 a.m. at the offices of ▇▇▇▇▇ & Lardner LLP at ▇▇▇ ▇▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇.

Type of Offering: Non-delayed

Date referred to in Section 5(h) after which the Company may offer or sell debt securities issued or guaranteed by the Company without the consent of the Representative(s): November 15, 2010.

Modification of items to be covered by the letter from

Deloitte & Touche LLP delivered pursuant to

Section 6(e) at the Execution Time: None.

SCHEDULE II

Underwriters	Principal Amount of Securities to be Purchased
Citigroup Global Markets Inc.	$	70,834,000
Mitsubishi UFJ Securities (USA), Inc..		70,833,000
▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. Incorporated		70,833,000
Mizuho Securities USA Inc.		12,500,000
Scotia Capital (USA) Inc.		12,500,000
U.S. Bancorp Investments, Inc.		12,500,000
Total	$	250,000,000

SCHEDULE III

[List of any FWPs included in the Disclosure Package to be inserted]

None, other than the Final Term Sheet included as Schedule IV

SCHEDULE IV

INTEGRYS ENERGY, INC.

FINAL TERM SHEET

Dated November 9, 2010

4.170% Senior Notes Due 2020

Issuer:	Integrys Energy Group, Inc.
Security:	4.170% Senior Notes Due 2020
Size:	$250,000,000
Maturity Date:	November 1, 2020
Coupon:	4.170%
Interest Payment Dates:	May 1 and November 1, commencing May 1, 2011
Price to Public:	99.937%
Benchmark Treasury:	2.625% due August 15, 2020
Benchmark Treasury Price:	99-31+
Benchmark Treasury Yield:	2.628%
Spread to Benchmark Treasury:	+ 155 basis points
Yield:	4.178%
Make-Whole Call:	T + 25 basis points
Expected Settlement Date:	November 15, 2010
CUSIP / ISIN:	45822P AA3 / US45822PAA30
Joint Book-Running Managers:	Citigroup Global Markets Inc. Mitsubishi UFJ Securities (USA), Inc. ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. Incorporated
Co-Managers:	Mizuho Securities USA Inc. Scotia Capital (USA) Inc. U.S. Bancorp Investments, Inc.

The issuer has filed a registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You may get these documents for free by visiting ▇▇▇▇▇ on the SEC Web site at ▇▇▇.▇▇▇.▇▇▇. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling Citigroup Global Markets Inc. toll free at 1-877-858-5407 or Mitsubishi UFJ Securities (USA), Inc. toll free at ▇-▇▇▇-▇▇▇-▇▇▇▇, or ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. Incorporated toll free at 1-866-718-1649.

INTEGRYS ENERGY GROUP, INC. Underwriting Agreement

Document Metadata

Document Metadata

Table of Contents