September 2, 2015

September 2, 0000

Xxxxx Xxxxxx Bank and Trust Company

Xxxxxx Xxxxxx Building

000 Xxxxxxx Xxxxxx

Xxxxx Xxxxxx, Xxxxxxxxxxxxx 00000

Location Code: JQB5

Attention: Xxxxxxx X. Xxxxxxx

Re: Master Custodian Agreement - New Portfolios

Ladies and Gentlemen:

Please be advised that the undersigned Fund has established two (2) new series of shares to be known as American Century Asset Allocation Portfolios, Inc. - One Choice 2060 Portfolio and American Century Asset Allocation Portfolios, Inc. - One Choice 2060 Portfolio R6 (the “New 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 respective New Portfolios under the terms of the Custodian Agreement. In connection with such request, each 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 two copies of this letter agreement, returning one to the Fund and retaining one for your records.

Sincerely,

American Century Asset Allocation Portfolios, Inc. on behalf of One Choice 2060 Portfolio and One Choice 2060 Portfolio R6

By:     /s/ C. Xxxx Xxxx

Name: C. Xxxx Xxxx

Title: Vice President, Duly Authorized

Agreed and Accepted:

STATE STREET BANK AND TRUST COMPANY

By: /s/ Xxxxxx Xxxxx

Name: Xxxxxx Xxxxx

Title: Executive Vice President, Duly Authorized

Effective Date: September 30, 2015