The rating on the proposed issue of renminbi-denominated senior unsecured notes reflects the "long-term counterparty credit rating" on the bank, S&P said in a statement.
"The proposed notes will constitute direct, unconditional, unsecured, and unsubordinated obligations of ICICI Bank," it said.
The proposed notes having 3-year maturity would be listed on the Singapore stock exchange.
Meanwhile another global rating agency, Moody's has assigned a Baa2 rating to ICICI Bank's proposed issuance of senior unsecured notes under its USD 5 billion Global Medium Term Note (GMTN) program.
"The ratings capture the bank's solid franchise as the second largest commercial bank in India as well as its strong capitalisation, liquidity, and earnings profile," Moody's said in a statement.
The ratings also reflect the bank's high borrower concentration in the form of its mandatory government securities portfolio, its weaker asset quality when compared to its Indian private sector peer banks and the difficult operating environment currently prevailing in India, including the intense competition it faces in its domestic markets, it added.