The agency also affirmed the B short-term counterparty credit and ruAA- Russian national scale ratings for one of Russia's 10 largest banks. The outlook remains positive.
"The upgrade reflects Rosbank's improving commercial and financial profile," said S&P credit analyst Eugene Tarzimanov.
Experts said support from minority shareholder French group Societe Generale (19.99%), Rosbank's granular loan portfolio, and expectations of higher core profitability in the medium term, bolstered the bank's current ratings.
"We expect SocGen's operational and managerial support to intensify in the medium term, positively affecting Rosbank in areas such as funding, risk management, and IT," said Tarzimanov.
SocGen's commitment to Rosbank is relatively limited at present, he said, adding that a further ratings upside was likely if SocGen acquired a controlling stake in Rosbank, a move thought quite possible.
"We would also consider raising the ratings if the bank demonstrates its ability to withstand competitive pressure on profitability and maintains good asset quality," the expert said.
According to S&P, ratings downside might follow a significant reduction in SocGen's support, the bank's inability to control the quality of its rapidly growing loan portfolio, or its failure to reap financial benefits from its network.
Majority-owned by Russian financial holding Interros (69.85%), Rosbank is one of the largest privately owned banks in Russia and operates about 650 outlets, including 67 branches, in most Russian regions.
