Underwriting Agreement, dated September 19, 2019, among Interstate Power and Light Company and the underwriters named therein

Interstate Power and Light Company, an Iowa corporation (the “Company”), confirms its agreement (the “Agreement”) with J.P. Morgan Securities LLC (“J.P. Morgan”), MUFG Securities Americas Inc. (“MUFG”) and Wells Fargo Securities, LLC (“Wells Fargo”), and each of the other underwriters named on Schedule A hereto (collectively, the “Underwriters”, which term shall also include any underwriter substituted as hereinafter provided in Section 10 hereof), for whom J.P. Morgan, MUFG and Wells Fargo are acting as representatives (in such capacity, the “Representatives”), with respect to the issue and sale by the Company and the purchase by the Underwriters, acting severally and not jointly, of the respective principal amounts set forth on Schedule A of $300,000,000 aggregate principal amount of the Company’s 3.500% Senior Debentures due 2049 (the “Securities”). The Securities will be issued pursuant to an indenture dated as of August 20, 2003 (the “Base Indenture”) between the Company and The Bank of New York Mellon Trust Company, N.A. as successor trustee thereunder (the “Trustee”). The term “Indenture,” as used herein, includes the Base Indenture and the Officer’s Certificate (as defined in the Base Indenture) to be executed in connection with the offering of the Securities, establishing the form and terms of the Securities pursuant to Section 301 of the Base Indenture. The Securities are to be issued in book-entry form and will be registered in the name of Cede & Co. as nominee of The Depository Trust Company (“DTC”) pursuant to the blanket letter agreement, dated October 1, 2003, between the Company and DTC.

The Company understands that the Underwriters propose to make a public offering of the Securities as soon as the Representatives deem advisable after this Agreement has been executed and delivered.

The Company has filed with the Securities and Exchange Commission (the “Commission”) an automatic shelf registration statement on Form S-3 (No. 333-222076-02), including a base prospectus (the “Base Prospectus”), for the registration of certain securities, including the Securities, under the Securities Act of 1933, as amended (the “1933 Act”), and the offering thereof from time to time in accordance with Rule 415 of the rules and regulations of the Commission under the 1933 Act (the “1933 Act Regulations”), which automatic shelf registration statement became effective under the 1933 Act upon filing with the Commission. Promptly after execution and delivery of this Agreement, the Company will prepare and file a prospectus supplement relating to the Securities in accordance with the provisions of Rule 430B (“Rule 430B”) of the 1933 Act Regulations and paragraph (b) of Rule 424 (“Rule 424(b)”) of the 1933 Act Regulations. Any information included in such prospectus supplement that was omitted from the Registration Statement at the time it first became effective but that is deemed to be a part of and included in such registration statement pursuant to Rule 430B is referred to as “Rule 430B Information.” Such registration statement, at any given time, including the amendments thereto to such time, the exhibits and schedules thereto, at such time, and the Rule 430B Information, is referred to herein as the “Registration Statement.” The final prospectus supplement, together with the Base Prospectus, in the form first furnished to the Representatives by the Company for use in connection with the offering of the Securities, is referred to herein as the “Prospectus.” A “preliminary prospectus” shall be deemed to refer to any preliminary prospectus supplement, together with the Base Prospectus, used in connection with the offering of the Securities that omitted the Rule 430B Information. For the purposes of this Agreement, all references to the “Registration Statement,” the “Prospectus” or any preliminary prospectus shall also be deemed to include all documents incorporated therein by reference pursuant to Item 12 of Form S-3 under the 1933 Act at such time and the documents otherwise deemed to be a part thereof or included therein by the 1933 Act Regulations. For purposes of this Agreement, all references to the Registration Statement, Prospectus or preliminary prospectus or to any amendment or supplement to any of the foregoing shall be deemed to include any copy filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval system (“EDGAR”).

All references in this Agreement to financial statements and schedules and other information which are “contained,” “included” or “stated” (or other references of like import) in the Registration Statement, Prospectus or preliminary prospectus shall be deemed to mean and include all such financial statements and schedules and other information which are incorporated by reference in or otherwise deemed by 1933 Act Regulations to be a part of or included in, as of such applicable date, the Registration Statement, Prospectus or preliminary prospectus, as the case may be.

At the time the Registration Statement became effective (including without limitation any effective dates of any amendments thereto and each deemed effective date with respect to the Underwriters pursuant to Rule 430B(f)(2) of the 1933 Act Regulations) and at the Closing Time, the Registration Statement and any amendments and supplements thereto complied or will comply, as the case may be, in all material respects with the requirements of the 1933 Act and the 1933 Act Regulations and the Trust Indenture Act of 1939, as amended (the “1939 Act”) and the rules and regulations of the Commission under the 1939 Act (the “1939 Act Regulations”), and did not or will not, as the case may be, contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading and the Indenture complied and will comply in all material respects with the requirements of the 1939 Act. Neither the Prospectus nor any amendments or supplements thereto, at the time the Prospectus or any such amendment or supplement was issued and at the Closing Time included or will include an untrue statement of a material fact or omitted or will 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. The representations and warranties in this subsection shall not apply to statements in or omissions from the Registration Statement or Prospectus made in reliance upon and in conformity with information furnished to the Company in writing by any Underwriter through the Representatives expressly for use in the Registration Statement (or any amendment thereto) or Prospectus (or any amendment thereto), it being understood and agreed that the only such information consists of the information contained in Schedule E hereto.

Each preliminary prospectus and the prospectus filed as part of the Registration Statement as originally filed or as part of any amendment thereto, or filed pursuant to Rule 424 under the 1933 Act, complied when so filed in all material respects with the 1933 Act Regulations and each preliminary prospectus and the Prospectus delivered to the Underwriters for use in connection with this offering was identical to the electronically transmitted copies thereof filed with the Commission pursuant to EDGAR, except to the extent permitted by Regulation S-T.

As of the Applicable Time (as defined below), neither (x) the Issuer Free Writing Prospectus(es) (as defined below) listed on Schedule B and the Statutory Prospectus (as defined below), all considered together (collectively, the “General Disclosure Package”), nor (y) any individual Issuer Free Writing Prospectus, when considered together with the General Disclosure Package, will include 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.

At the time of filing the Registration Statement, at the earliest time thereafter that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2) of the 1933 Act Regulations) of the Securities and at the date hereof, the Company was not and is not an “ineligible issuer,” as defined in Rule 405.

As used in this subsection and elsewhere in this Agreement:

“Applicable Time” means 3:10 P.M. (Eastern time) on the date of this Agreement.

“Statutory Prospectus” as of any time means the prospectus relating to the Securities that is included in the Registration Statement immediately prior to that time, including any document incorporated by reference therein and any preliminary or other prospectus supplement deemed to be a part thereof.

“Issuer Free Writing Prospectus” means any “issuer free writing prospectus,” as defined in Rule 433 (“Rule 433”) of the 1933 Act Regulations, relating to the Securities that (i) is required to be filed with the Commission by the Company or (ii) is exempt from filing pursuant to Rule 433(d)(5)(i) because it contains a description of the Securities or of the offering that does not reflect the final terms, in each case in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g) or is exempt from filing pursuant to Rule 433(d)(8)(i) relating to road shows.

Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Securities or until any earlier date that the issuer notified or notifies the Representatives as described in the next sentence, did not, does not and will not include any information that conflicted, conflicts or will conflict with the information contained in the Registration Statement or the Prospectus, including any document incorporated by reference therein and any preliminary or other prospectus deemed to be a part thereof that has not been superseded or modified. If at any time following issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus included or would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances, not misleading, the Company has notified or will notify promptly the Representatives so that any use of such Issuer Free Writing Prospectus may cease until it is amended or supplemented. The foregoing two sentences do 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 expressly for use therein, it being understood and agreed that the only such information consists of the information contained in Schedule E hereto.

(A)The documents incorporated or deemed to be incorporated by reference in the Registration Statement, the Statutory Prospectus and the Prospectus, at the time they were or hereafter are filed with the Commission, complied or will comply, as the case may be, in all material respects with the requirements of the 1934 Act and the rules and regulations of the Commission thereunder (the “1934 Act Regulations”), as applicable, and, when read together with the other information in the Registration Statement, the Statutory Prospectus and the Prospectus, did not or will not, as the case may be, contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading.

(B)The description of regulatory matters to which the Company is subject, as disclosed in the Company’s filings with the Commission under the 1934 Act and the 1934 Act Regulations and as incorporated by reference into the Registration Statement, is true and correct in all material respects, except to the extent such description in any specific filing has been superseded, updated or supplemented by such description in a subsequent filing under the 1934 Act or the 1934 Act Regulations made prior to the date hereof or by such description in the Statutory Prospectus and the Prospectus.

and Instruments except for such conflicts, breaches or defaults or liens, charges or encumbrances that, singly or in the aggregate, would not result in a Material Adverse Effect, nor will such action result in any violation of the provisions of (I) the articles of incorporation or bylaws, each as amended, of the Company or any of its subsidiaries or (II) any applicable law, statute, rule, regulation, judgment, order, writ or decree of any government, government instrumentality or court, domestic or foreign, having jurisdiction over the Company or any of its subsidiaries or any of their assets, properties or operations, except for any such violations with respect to this clause (II) as would not, individually or in the aggregate, result in a Material Adverse Effect. As used herein, a “Repayment Event” means any event or condition which gives the holder of any note, debenture or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of its subsidiaries.

The Company together with its consolidated subsidiaries employs disclosure controls and procedures that are designed to ensure that information required to be disclosed by the Company in the reports that it files or submits under the 1934 Act is recorded, processed, summarized and reported, within the time periods specified in the Commission’s rules and forms, and is accumulated and communicated to the Company’s management, including its principal executive officer or officers and principal financial officer or officers, as appropriate, to allow timely decisions regarding disclosure.

(xxiv)Cybersecurity.. The Company and its subsidiaries’ information technology assets and equipment, computers, systems, networks, hardware, software, websites, applications, and databases (collectively, “IT Systems”) are adequate for, and operate and perform in all material respects as required in connection with the operation of the business of the Company and its subsidiaries as currently conducted, free and clear of all material bugs, errors, defects, Trojan horses, time bombs, malware and other corruptants. The Company and its subsidiaries have implemented and maintained commercially reasonable controls, policies, procedures, and safeguards to maintain and protect their material confidential information and the integrity, continuous operation, redundancy and security of all IT Systems and data (including all personal, personally identifiable, sensitive, confidential or regulated data (“Personal Data”)) used in connection with their businesses, and there have been no breaches, violations, outages or unauthorized uses of or accesses to same, except for those that have been remedied without material cost or liability or the duty to notify any other person, nor any incidents under internal review or investigations relating to the same. The Company and its subsidiaries are presently in material compliance with all applicable laws or statutes and all judgments, orders, rules and regulations of any court or arbitrator or governmental or regulatory authority, internal policies and contractual obligations relating to the privacy and security of IT Systems and Personal Data and to the protection of such IT Systems and Personal Data from unauthorized use, access, misappropriation or modification.

(xxv)Foreign Corrupt Practices Act. Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee, affiliate or other person acting on behalf of the Company or any of its subsidiaries is aware of or has taken any action, directly or indirectly, that could result in a violation or a sanction for violation by such persons of the Foreign Corrupt Practices Act of 1977, as amended, or the rules or regulations thereunder; and the Company and its subsidiaries have instituted and maintain policies and procedures to ensure compliance therewith. Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee, affiliate or other person acting on behalf of the Company or any of its subsidiaries will use any part of the proceeds of the offering, directly or indirectly, in violation of the Foreign Corrupt Practices Act of 1977, as amended, or the rules or regulations thereunder.

(xxvi)Money Laundering Laws. The operations of the Company and its subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements, including any money laundering statutes and the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator is pending or, to the best knowledge of the Company, threatened against the Company or any of its subsidiaries with respect to the Money Laundering Laws.

(xxvii)OFAC. Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee, affiliate or other person acting on behalf of the Company or any of its subsidiaries (i) is, or is controlled or 50% or more owned by or is acting on behalf of, an individual or entity that is currently the subject of any sanctions administered or enforced by the United States (including any administered or enforced by the Office of Foreign Assets Control of the U.S. Department of the Treasury, the U.S. Department of State or the Bureau of Industry and Security of the U.S. Department of Commerce), the United Nations Security Council, the European Union, the United Kingdom (including sanctions administered or enforced by Her Majesty’s Treasury) or other relevant sanctions authority (collectively, “Sanctions”), (ii) is located, organized or resident in a country or territory that is, or whose government is, the subject of Sanctions that broadly prohibit dealings with that country or territory (the “Sanctioned Countries”) or (iii) will, directly or indirectly, use the proceeds of this offering, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other individual or entity in any manner that would result in a violation of any Sanctions by, or could result in the imposition of Sanctions against, any individual or entity (including any individual or entity participating in the offering, whether as underwriter, advisor, investor or otherwise). The Company and its subsidiaries (as of the date hereof) have not knowingly engaged in, are not now knowingly engaged in and will not knowingly engage in any dealings or transactions with any person that at the time of the dealing or transaction is or was the subject or the target of Sanctions or with any of the Sanctioned Countries, in each case if such dealing or transaction is prohibited by law.

(xxviii)No Price Stabilization or Manipulation. The Company has not taken, directly or indirectly, any action designed to or that could reasonably be expected to cause or result in any stabilization or manipulation of the price of the Securities.

(b)Officer’s Certificates. Any certificate signed by any officer of the Company or any of its subsidiaries delivered to the Representatives or to counsel for the Underwriters shall be deemed a representation and warranty by the Company to each Underwriter as to the matters covered thereby.

Payment shall be made to the Company by wire transfer of immediately available funds to a bank account designated by the Company, against delivery to the Representatives for the respective accounts of the Underwriters of certificates for the Securities to be purchased by them. It is understood that each Underwriter has authorized the Representatives, for its account, to accept delivery of, receipt for, and make payment of the purchase price for, the Securities that it has agreed to purchase.

Underwriters such number of copies of such amendment or supplement as the Underwriters may reasonably request.

SECTION 5.Conditions of Underwriters’ Obligations. The obligations of the several Underwriters hereunder are subject to the accuracy in all material respects of the representations and warranties of the Company contained in Section 1 hereof or in certificates of any officer of the Company or any subsidiary of the Company delivered pursuant to the provisions hereof, to the performance in all material respects by the Company of its covenants and other obligations hereunder, and to the following further conditions:

provided, however, that this indemnity shall not apply to any loss, liability, claim, damage or expense to the extent arising out of any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives expressly for use in the Registration Statement (or any amendment thereto), or any preliminary prospectus, Issuer Free Writing Prospectus or the Prospectus (or any amendment or supplement thereto), it being understood and agreed that the only such information consists of the information contained in Schedule E hereto.

not (except with the consent of the indemnified party) also be counsel to the indemnified party. In no event shall the indemnifying parties be liable for fees and expenses of more than one counsel (in addition to any local counsel) separate from their own counsel for all indemnified parties in connection with any one action or separate but similar or related actions in the same jurisdiction arising out of the same general allegations or circumstances. In addition, the indemnifying party shall be entitled, to the extent that it wishes, jointly with any other similarly notified indemnifying party, to assume the defense of any claim or action brought against an indemnified party with counsel reasonably satisfactory to the indemnified party. After notice from the indemnifying party to the indemnified party of its election to assume the defense of such claim or action, the indemnifying party shall not be liable to the indemnified party under this Section 6 for any legal or other expenses subsequently incurred by the indemnified party in connection with the defense thereof other than reasonable costs of investigation; provided, however, that the Representatives shall have the right to employ one counsel (in addition to local counsel) to represent them and those other Underwriters and their respective officers, employees and controlling persons who may be subject to liability arising out of any claim in respect of which indemnity may be sought by the Underwriters against the Company under this Section 6 if, in the reasonable judgment of the Representatives, either (i) there is an actual or potential conflict between the position of the Company on the one hand and the Underwriters on the other hand or (ii) there may be defenses available to it or them that are different from or additional to those available to the Company (in any of which events the Company shall not have the right to direct the defense of such action on behalf of the Representatives with respect to such different defenses), in any of which events such reasonable fees and expenses shall be borne by the Company. No indemnifying party shall, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever in respect of which indemnification or contribution could be sought under this Section 6 or Section 7 hereof (whether or not the indemnified parties are actual or potential parties thereto), unless such settlement, compromise or consent (A) includes an unconditional release of each indemnified party from all liability arising out of such litigation, investigation, proceeding or claim and (B) does not include a statement as to or an admission of fault, culpability or a failure to act by or on behalf of any indemnified party.

SECTION 7.Contribution. If the indemnification provided for in Section 6 hereof is for any reason unavailable to or insufficient to hold harmless an indemnified party in respect of any losses, liabilities, claims, damages or expenses referred to therein, then each indemnifying party shall contribute to the aggregate amount of such losses, liabilities, claims, damages and expenses incurred by such indemnified party, as incurred, (a) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other hand from the offering of the Securities pursuant to this Agreement or (b) if the allocation provided by clause (a) is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (a) above but also the relative fault of the Company on the one hand and of the Underwriters on the other hand in connection with the statements or omissions, which resulted in such losses, liabilities, claims, damages or expenses, as well as any other relevant equitable considerations.

The relative benefits received by the Company on the one hand and the Underwriters on the other hand in connection with the offering of the Securities pursuant to this Agreement shall be deemed to be in the same respective proportions as the total net proceeds from the offering of the Securities pursuant to this Agreement (before deducting expenses) received by the Company and the total underwriting discount received by the Underwriters, in each case as set forth on the cover of the Prospectus, bear to the aggregate initial public offering price of the Securities as set forth on such cover.

The relative fault of the Company on the one hand and the Underwriters on the other hand shall be determined by reference to, among other things, whether any such untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material fact relates to information supplied by the Company or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 7 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to above in this Section 7. The aggregate amount of losses, liabilities, claims, damages and expenses incurred by an indemnified party and referred to above in this Section 7 shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in investigating, preparing or defending against any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever based upon any such untrue or alleged untrue statement or omission or alleged omission.

Notwithstanding the provisions of this Section 7, no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Securities underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of any such untrue or alleged untrue statement or omission or alleged omission.

No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the 1933 Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation.

For purposes of this Section 7, each person, if any, who controls an Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act shall have the same rights to contribution as such Underwriter, and each director of the Company, each officer of the Company who signed the Registration Statement, and each person, if any, who controls the Company within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act shall have the same rights to contribution as the Company. The Underwriters’ respective obligations to contribute pursuant to this Section 7 are several in proportion to the principal amount of Securities set forth opposite their respective names in Schedule A hereto and not joint.

SECTION 8.Representations, Warranties and Agreements to Survive Delivery. All representations, warranties and agreements contained in this Agreement or in certificates of officers of the Company or any of its subsidiaries submitted pursuant hereto, shall remain operative and in full force and effect, regardless of any investigation made by or on behalf of any Underwriter or controlling person, or by or on behalf of the Company, and shall survive delivery of and payment for the Securities to the Underwriters.

SECTION 10.Default by One or More of the Underwriters. If one or more of the Underwriters shall fail at the Closing Time to purchase the Securities which it or they are obligated to purchase under this Agreement (the “Defaulted Securities”), the Representatives shall have the right, within 24 hours thereafter, to make arrangements for one or more of the non-defaulting Underwriters, or any other underwriters, to purchase all, but not less than all, of the Defaulted Securities in such amounts as may be agreed upon and upon the terms herein set forth; if, however, the Representatives shall not have completed such arrangements within such 24-hour period, then:

No action taken pursuant to this Section 10 shall relieve any defaulting Underwriter from liability in respect of its default.

In the event of any such default which does not result in a termination of this Agreement, either the Representatives or the Company shall have the right to postpone the Closing Time for a period not exceeding seven days in order to effect any required changes in the Registration Statement or Prospectus or in any other documents or arrangements. As used herein, the term “Underwriter” includes any person substituted for an Underwriter under this Section 10.

SECTION 11.Certain Agreements of the Underwriters. Each Underwriter hereby represents and agrees that:

SECTION 12.Notices. All notices and other communications hereunder shall be in writing and shall be deemed to have been duly given if mailed or transmitted by any standard form of telecommunication. Notices to the Underwriters shall be directed to the Representatives at:

and notices to the Company shall be directed to it at 4902 North Biltmore Lane, Madison, Wisconsin 53718, attention of Barbara Tormaschy, Vice President and Treasurer, or her successor (telephone: (608) 458-3114; facsimile: (608) 458-0130).

SECTION 13.Parties. This Agreement shall inure to the benefit of and be binding upon each of the Underwriters and the Company and their respective successors. Nothing expressed or mentioned in this Agreement is intended or shall be construed to give any person, firm or corporation, other than the Underwriters and the Company and their respective successors and the controlling persons and officers and directors referred to in Sections 6 and 7 and their heirs and legal representatives, any legal or equitable right, remedy or claim under or in respect of this Agreement or any provision herein contained. This Agreement and all conditions and provisions hereof are intended to be for the sole and exclusive benefit of the Underwriters and the Company and their respective successors, and said controlling persons and officers and directors and their heirs and legal representatives, and for the benefit of no other person, firm or corporation. No purchaser of Securities from any Underwriter shall be deemed to be a successor by reason merely of such purchase.

SECTION 14.No Fiduciary Duty. The Company hereby acknowledges that the Underwriters will be acting pursuant to a contractual relationship on an arm’s length basis and in no event do the parties intend that the Underwriters act or be responsible as a fiduciary to the Company, its management, stockholders, creditors or any other person. The Company and the Underwriters each hereby expressly disclaim any fiduciary relationship and agree they are each responsible for making their own independent judgments with respect to any transactions entered into between them.

SECTION 15.GOVERNING LAW AND TIME. THIS AGREEMENT AND ALL DISPUTES, CONTROVERSIES OR CLAIMS ARISING OUT OF OR RELATING TO THIS AGREEMENT OR A BREACH HEREOF SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK. EXCEPT AS OTHERWISE SET FORTH HEREIN, SPECIFIED TIMES OF DAY REFER TO NEW YORK CITY TIME.

SECTION 16.Patriot Act. In accordance with the requirements of the USA Patriot Act (Title III of Pub. L, 107-56 (signed into law October 26, 2001)), the Underwriters are required to obtain, verify and record information that identifies their clients, which may include the name and address of their clients, as well as other information that will allow the Underwriters to properly identify their clients.

SECTION 17.Recognition of the U.S. Special Resolution Regimes.

For purposes of this Section 17:

“BHC Act Affiliate” has the meaning assigned to the term “affiliate” in, and shall be interpreted in accordance with, 12 U.S.C. § 1841(k).

“Covered Entity” means any of the following:

“Default Right” has the meaning assigned to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable.

“U.S. Special Resolution Regime” means each of (i) the Federal Deposit Insurance Act and the regulations promulgated thereunder and (ii) Title II of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations promulgated thereunder.

SECTION 18.Effect of Headings. The Article and Section headings herein and the Table of Contents are for convenience only and shall not affect the construction hereof.

SECTION 19.Counterparts. This Agreement may be executed in one or more counterparts and, if executed in more than one counterpart, the executed counterparts shall constitute a single instrument.

If the foregoing is in accordance with your understanding of our agreement, please sign and return to the Company a counterpart hereof, whereupon this instrument, along with all counterparts, will become a binding agreement between the Underwriters and the Company in accordance with its terms.

INTERSTATE POWER AND LIGHT COMPANY

CONFIRMED AND ACCEPTED,

as of the date first above written:

J.P. MORGAN SECURITIES LLC

By: /s/ Som Bhattacharyya

MUFG SECURITIES AMERICAS INC.

By: /s/ Richard Testa

WELLS FARGO SECURITIES, LLC

By: /s/ Carolyn Hurley

1.    The initial public offering price of the Securities shall be 99.668% of the principal amount thereof, plus accrued interest, if any, from the date of issuance.

2.    The purchase price to be paid by the Underwriters for the Securities shall be 98.793% of the principal amount thereof.

3.    The interest rate on the Securities shall be 3.500% per annum.

4.    At any time prior to March 30, 2049 (the “Par Call Date”), the Securities will be redeemable as a whole or in part, at the Company’s option, at a redemption price equal to the greater of (i) 100% of the principal amount of such Securities and (ii) the sum, as determined by the Independent Investment Banker and delivered to the Trustee, of the present values of the remaining scheduled payments of principal and interest thereon that would be due if the Securities matured on the Par Call Date (exclusive of interest accrued to the date of redemption) discounted to the redemption date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 20 basis points, plus in each case accrued and unpaid interest, if any, to, but excluding, the redemption date. On or after the Par Call Date, the Securities will be redeemable as a whole or in part, at the Company’s option, at a redemption price equal to 100% of the principal amount of the Securities being redeemed plus accrued and unpaid interest, if any, to, but excluding, the redemption date.

“Comparable Treasury Issue” means the United States Treasury security or securities selected by an Independent Investment Banker as having an actual or interpolated maturity comparable to the remaining term of the Securities (assuming for this purpose that the Securities matured on the applicable Par Call Date) to be redeemed that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of a comparable maturity to the remaining term of such Securities.

“Comparable Treasury Price” means, with respect to any redemption date, (A) the average of the Reference Treasury Dealer Quotations for such redemption date, after excluding the highest and lowest such Reference Treasury Dealer Quotations, or (B) if the Independent Investment Banker obtains fewer than four such Reference Treasury Dealer Quotations, the average of all such quotations.

“Independent Investment Banker” means one of the Reference Treasury Dealers appointed by the Company.

“Reference Treasury Dealer” means each of (i) J.P. Morgan Securities LLC, (ii) Wells Fargo Securities, LLC and (iii) a primary treasury dealer selected by MUFG Securities Americas Inc., or their affiliates, which are primary United States government securities dealers and (iv) one other leading primary U.S. government securities dealer located in the United States (a “Primary Treasury Dealer”) reasonably selected by us, and such Primary Treasury Dealer’s successors that we specify from time to time; provided, however, that if any of the foregoing or their affiliates cease to be a Primary Treasury Dealer, we will substitute therefor another Primary Treasury Dealer.

“Reference Treasury Dealer Quotations” means, with respect to each Reference Treasury Dealer and any redemption date, the average, as determined by the Independent Investment Banker, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Independent Investment Banker by the Reference Treasury Dealers at 3:30 P.M. New York time on the third business day preceding such redemption date.

“Treasury Rate” means, with respect to any redemption date, the rate per annum equal to the semiannual equivalent yield to maturity or interpolated (on a day count basis) of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for such redemption date.