Report of Foreign Issuer (6-k)

FORM 6-K

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Report of Foreign Issuer

Pursuant to Rule 13a-16 or 15d-16 of
the Securities Exchange Act of 1934

For the month of August, 2017

Commission File Number: 001-15002

ICICI Bank Limited
(Translation of registrant’s name into English)

ICICI Bank Towers,
Bandra-Kurla Complex
Mumbai, India 400 051
(Address of principal executive office)

Indicate by check mark whether the registrant files or will file
annual reports under cover Form 20-F or Form 40-F.

Form 20-F X

Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K
in paper as permitted by Regulation S-T Rule 101(b)(1):

Yes

No X

Indicate by check mark if the registrant is submitting the Form 6-K
in paper as permitted by Regulation S-T Rule 101(b)(7):

Yes

No X

Indicate by check mark whether by furnishing the information
contained in this Form, the Registrant is also thereby furnishing the
information to the Commission pursuant to Rule 12g3-2(b)
under the Securities Exchange Act of 1934:

Yes

No X

If “Yes” is marked, indicate below the file number assigned to the registrant in
connection with Rule 12g 3-2(b): Not Applicable

Table of Contents

Item

1.	Release dated August 17, 2017

Rating Action: Moody's affirms Baa3 senior unsecured debt ratings of ICICI Bank's Bahrain branch

Global Credit Research - 17 Aug 2017

Singapore, August 17, 2017 -- Moody's Investors Service has affirmed the Baa3 foreign currency senior unsecured debt ratings of ICICI Bank Limited's Bahrain branch.

At the same time, Moody's has downgraded the provisional ratings on the foreign currency senior unsecured MTN program for the bank's Bahrain branch to (P)Ba2 from (P)Baa3, because the foreign currency bond ceiling for Bahrain is now at Ba2. The branch's counterparty risk assessment (CRA) has also been downgraded to Ba1(cr)/Not Prime(cr) from Baa3(cr)/P-3(cr), because Moody's downgraded the local currency country risk ceiling for Bahrain to Ba1.

All other ratings under the MTN program remain unchanged.

The outlook on all ratings, where applicable, is stable.

RATINGS RATIONALE

Moody's has affirmed the ratings on the outstanding foreign currency senior unsecured bonds issued by the Bahrain branch under the MTN program at Baa3, on the basis of an irrevocable and unconditional standby letter of credit (SBLC) on these outstanding bonds through ICICI's Dubai branch. The features of the SBLC satisfy the key criteria required to achieve full credit substitution. Consequently, the ratings of these instruments are in line with the Baa3 foreign currency senior unsecured ratings of the Dubai branch.

Moody's has also affirmed the foreign currency senior unsecured debt rating of the Bahrain branch, as the only bonds outstanding are those covered by the SBLC. The bank has indicated that they will not be issuing any more bonds out of the Bahrain branch.

The downgrading of the provisional ratings on the foreign currency senior unsecured MTN program for the bank's Bahrain branch to (P)Ba2 is solely on account of the foreign currency bond ceiling of Bahrain, which was downgraded to Ba2. Similarly, the downgrading of the branch's CRA to Ba1(cr)/NP(cr) is solely on account of the local currency country risk ceilings of Bahrain, which Moody's downgraded to Ba1.

No ratings for the other branches of ICICI Bank were affected.

BACKGROUND

ICICI Bank Limited is headquartered in Mumbai. As of June 2017, the bank reported standalone assets of INR7.61 trillion (approximately USD117.7 billion).

The methodologies used in these ratings were Banks published in January 2016, and Rating Transactions Based on the Credit Substitution Approach: Letter of Credit-backed, Insured and Guaranteed Debts published in May 2017. Please see the Rating Methodologies page on www.moodys.com for a copy of these methodologies.

REGULATORY DISCLOSURES

For ratings issued on a program, series or category/class of debt, this announcement provides certain regulatory disclosures in relation to each rating of a subsequently issued bond or note of the same series or category/class of debt or pursuant to a program for which the ratings are derived exclusively from existing ratings in accordance with Moody's rating practices. For ratings issued on a support provider, this announcement provides certain regulatory disclosures in relation to the credit rating action on the support provider and in relation to each particular credit rating action for securities that derive their credit ratings from the support provider's credit rating. For provisional ratings, this announcement provides certain regulatory disclosures in relation to the provisional rating assigned, and in relation to a definitive rating that may be assigned subsequent to the final issuance of the debt, in each case where the transaction structure and terms

have not changed prior to the assignment of the definitive rating in a manner that would have affected the rating. For further information please see the ratings tab on the issuer/entity page for the respective issuer on www.moodys.com.

For any affected securities or rated entities receiving direct credit support from the primary entity(ies) of this credit rating action, and whose ratings may change as a result of this credit rating action, the associated regulatory disclosures will be those of the guarantor entity. Exceptions to this approach exist for the following disclosures, if applicable to jurisdiction: Ancillary Services, Disclosure to rated entity, Disclosure from rated entity.

Regulatory disclosures contained in this press release apply to the credit rating and, if applicable, the related rating outlook or rating review.

Please see www.moodys.com for any updates on changes to the lead rating analyst and to the Moody's legal entity that has issued the rating.

Please see the ratings tab on the issuer/entity page on www.moodys.com for additional regulatory disclosures for each credit rating.

Srikanth Vadlamani

VP - Senior Credit Officer

Financial Institutions Group

Moody's Investors Service Singapore Pte. Ltd.

50 Raffles Place #23-06

Singapore Land Tower

Singapore 48623

Singapore

JOURNALISTS: 852 3758 1350

Client Service: 852 3551 3077

Gene Fang

Associate Managing Director

Financial Institutions Group

JOURNALISTS: 852 3758 1350

Client Service: 852 3551 3077

Releasing Office:

Moody's Investors Service Singapore Pte. Ltd.

50 Raffles Place #23-06

Singapore Land Tower

Singapore 48623

Singapore

JOURNALISTS: 852 3758 1350

Client Service: 852 3551 3077

CREDIT RATINGS ISSUED BY MOODY'S INVESTORS SERVICE, INC. AND ITS RATINGS AFFILIATES (“MIS”) ARE MOODY’S CURRENT OPINIONS OF THE RELATIVE FUTURE CREDIT RISK OF ENTITIES, CREDIT COMMITMENTS, OR DEBT OR DEBT-LIKE SECURITIES, AND MOODY’S PUBLICATIONS MAY INCLUDE MOODY’S CURRENT OPINIONS OF THE RELATIVE FUTURE CREDIT RISK OF ENTITIES, CREDIT COMMITMENTS, OR DEBT OR DEBT-LIKE SECURITIES. MOODY’S DEFINES CREDIT RISK AS THE RISK THAT AN ENTITY MAY NOT MEET ITS CONTRACTUAL, FINANCIAL OBLIGATIONS AS THEY COME DUE AND ANY ESTIMATED FINANCIAL LOSS IN THE EVENT OF DEFAULT. CREDIT RATINGS DO NOT ADDRESS ANY OTHER RISK, INCLUDING BUT NOT LIMITED TO: LIQUIDITY RISK, MARKET VALUE RISK, OR PRICE VOLATILITY. CREDIT RATINGS AND MOODY’S OPINIONS INCLUDED IN MOODY’S

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Moody’s Investors Service, Inc., a wholly-owned credit rating agency subsidiary of Moody’s Corporation (“MCO”), hereby discloses that most issuers of debt securities (including corporate and municipal bonds, debentures, notes and commercial paper) and preferred stock rated by Moody’s Investors Service, Inc. have, prior to assignment of any rating, agreed to pay to Moody’s Investors Service, Inc. for appraisal and rating services rendered by it fees ranging from $1,500 to approximately $2,500,000. MCO and MIS also maintain

policies and procedures to address the independence of MIS’s ratings and rating processes. Information regarding certain affiliations that may exist between directors of MCO and rated entities, and between entities who hold ratings from MIS and have also publicly reported to the SEC an ownership interest in MCO of more than 5%, is posted annually at www.moodys.com under the heading “Investor Relations — Corporate Governance — Director and Shareholder Affiliation Policy.”

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MJKK and MSFJ also maintain policies and procedures to address Japanese regulatory requirements.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorised.