INTERSTATE POWER AND LIGHT COMPANY (an Iowa corporation) 3.100% SENIOR DEBENTURES DUE 2051 UNDERWRITING AGREEMENT Dated: November 16, 2021Underwriting Agreement • November 19th, 2021 • Interstate Power & Light Co • Electric & other services combined • New York
Interstate Power and Light Company, an Iowa corporation (the “Company”), confirms its agreement with Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC, MUFG Securities Americas Inc. and U.S. Bancorp Investments, Inc., and each of the other underwriters named in Schedule A hereto (collectively, the “Underwriters,” which term shall also include any underwriter substituted as hereinafter provided in Section 10 hereof), for whom Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC, MUFG Securities Americas Inc. and U.S. Bancorp Investments, Inc. 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 3.100% Senior Debentures due 2051 (the “Securities”). The Securities will be issued pursuant to an indenture dated as of August 20, 2003
