Exhibit (k.4)

November 14, 2014

State Street Bank and Trust Company

200 Newport Ave

North Quincy, MA 02171

Attention: Matthew H. Malkasian, Senior Vice President

Ladies and Gentlemen:

Please be advised that the undersigned Fund has been incorporated and registered as a management investment company under the Investment Company Act of 1940, as amended.

In accordance with Sections 8.5 (the additional funds provision) of the Master Services Agreement dated as of March 15, 2004, by and among each registered investment company party thereto and State Street Bank and Trust Company (as amended, modified or supplemented from time to time, the “Master Services Agreement”), the Fund hereby requests that your bank perform accounting and fund administration services for it under the terms of the Master Services Agreement.

In connection with such request the Fund: (i) confirms to you, as of the date hereof, its representations and warranties set forth in Section 4.2 of the Master Services Agreement; and (ii) for the avoidance of doubt, acknowledges and confirms to State Street that the letter agreement dated March 31, 2006 (“Third Side Letter”) by and among the Funds and State Street shall also apply to the Fund and the Fund agrees to be bound by all of the terms and conditions of the Third Side Letter.

Attached as Appendix A hereto is a replacement of “Appendix A” to the Agreement, effective as of the date set forth below.

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.

Agreed and Accepted:

STATE STREET BANK AND TRUST COMPANY

Effective Date: November 14, 2014

Appendix A

APPENDIX A

TO

MASTER SERVICES AGREEMENT

MANAGEMENT INVESTMENT COMPANIES REGISTERED WITH THE SEC AND PORTFOLIOS THEREOF, IF ANY

CALAMOS ADVISORS TRUST