INTERSTATE POWER AND LIGHT COMPANY (an Iowa corporation) 3.60% SENIOR DEBENTURES DUE 2029 UNDERWRITING AGREEMENT Dated: March 25, 2019Underwriting Agreement • April 1st, 2019 • Interstate Power & Light Co • Electric & other services combined • New York
Interstate Power and Light Company, an Iowa corporation (the “Company”), confirms its agreement (the “Agreement”) with Barclays Capital Inc. (“Barclays”), J.P. Morgan Securities LLC (“J.P. Morgan”) and Mizuho Securities USA LLC (“Mizuho”), 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 Barclays, J.P. Morgan and Mizuho 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 3.60% Senior Debentures due 2029 (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 Yo
