Apart from upgrading the rating to 'IND AA' from 'IND AA-', it also gave a stable outlook on the rating.
"The upgrade reflects an improvement in ING Vysya's credit profile as reflected in its stronger capitalisation levels and improving profitability buffers in the form of rising pre-provision operating profits (PPOP)," it said.
The rating agency said the ongoing economic gloom may have some impact on the bank's assets leading to a rise in delinquencies, but its high specific loan loss reserves and improving PPOP provide an adequate cushion.
The Bangalore-headquartered bank had a core Tier-I capital at 14.49 per cent as of December 2013, boosted by Rs 18.36 billion infusion in July 2013.
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It said the bank is likely to maintain an elevated Tier-I of over 11 per cent mainly in order to facilitate a smooth transition to the Basel III regime.
India Ratings also drew attention towards the high contribution (36.8 per cent) of the SME sector in the bank's total advances and added that it has been able to increase the yields from this segment, which shows it is able to price risk better.