Exhibit 2.3





|Deutsche Bank Trust Company Americas
        Issuer Services - Depositary Receipts | 
|---------------------------------------------------------------------------------- | 



STRICTLY PRIVATE AND CONFIDENTIAL



June 2, 2016



ICICI Bank Limited

ICICI Bank Towers

Bandra-Kurla Complex

Mumbai 400 051

India



|Attention: | Mr. Rakesh Jha, Chief Financial Officer
        Mr. Anindya Banerjee, Senior General Manager
|---------- | --------------------------------------------------------------------------------------------



Dear Mr. Jha, Mr. Banerjee:



This supplemental letter agreement will supplement the letter
agreement executed by ICICI Bank Limited (“ICICI”) and by Deutsche Bank Trust Company Americas (“Deutsche
Bank”) dated November 4, 2011 (the “Original Letter Agreement”). All capitalized terms used but not
otherwise defined herein shall have the meaning given to such terms in the Original Letter Agreement. All provisions of the Original
Letter Agreement shall remain in full force and effect, except where expressly supplemented hereby.



In furtherance of the relationship between the parties and for
consideration the sufficiency of which is hereby acknowledged, Deutsche Bank will, for the term we act as depositary bank for your
Facility, provide you with an annual intensive depositary receipt training session in New York or London for one of your senior
management, or an employee nominated by the senior management, at a time regularly scheduled by us, and reimburse your properly
documented related travel costs, such costs estimated and capped at US$10,000



The terms and provisions of this supplemental letter agreement
shall be governed by and construed in accordance with the laws of the State of New York.



The parties are signing this supplemental letter agreement on
the date first set forth above.



Yours sincerely,



|/s/ Michael Fitzpatrick                                           |                     | /s/ Michael Curran
|----------------------------------------------------------------- | ------------------- | ------------------
|Name:                                                             | Michael Fitzpatrick |                   
|Title:                                                            | Vice President      |                   
|                                                                  |                     |                   
|For and on behalf of
        DEUTSCHE BANK TRUST COMPANY AMERICAS
|                                                                 
|                                                                  |                     |                   
|ACKNOWLEDGED BY:                                                  |                     |                   
|                                                                  |                     |                   
|ICICI BANK LIMTED                                                 |                     |                   
|                                                                  |                     |                   
|/s/ Anindya Banerjee                                              |                     |                   
|Name: Anindya Banerjee                                            |                     |                   
|Title: Senior General Manager                                     |                     |                   





Confidential