November 30, 2020

State Street Bank and Trust Company

One Heritage Drive

North Quincy, Massachusetts 02171

Location Code: OHD0310

Attention:  Russell M. Donohoe

Re: Master Custodian Agreement – New Portfolios

Ladies and Gentlemen:

Please be advised that the undersigned Fund has established three (3) new series of shares to be known as:

American Century ETF Trust – American Century Quality Convertible Securities ETF

American Century ETF Trust – American Century Quality Preferred ETF

American Century ETF Trust – American Century Low Volatility ETF (the “New ETF Portfolios”).

In accordance with Section 18.6, the Additional Portfolios provision, of the Master Custodian Agreement dated as of July 29, 2011, (the “Custodian Agreement”) by and among each Fund party thereto and State Street Bank and Trust Company, the undersigned Fund hereby requests that your bank act as Custodian for the New ETF Portfolios under the terms of the Custodian Agreement. In connection with such request, the undersigned Fund hereby confirms to you, as of the date hereof, its representations and warranties set forth in Section 18.7 of the Custodian Agreement. Capitalized terms used herein without definition shall have the meanings ascribed to them in the Custodian Agreement.

Kindly indicate your acceptance of the foregoing by executing this letter agreement and returning a copy to the Fund.

        Sincerely,

        American Century Investment Management, Inc. on behalf of     

        American Century ETF Trust – American Century Quality Convertible Securities ETF

American Century ETF Trust – American Century Quality Preferred ETF

American Century ETF Trust – American Century Low Volatility ETF

            By:     /s/ Otis H. Cowan

                Otis H. Cowan

            Title:     Vice President, Duly Authorized

Agreed and Accepted:

STATE STREET BANK AND TRUST COMPANY

By:     /s/ Michael A. Foutes

Name:    Michael A. Foutes

Title:    Managing Director

Effective Date: November 30, 2020