Global rating agency Standard & Poor's has revised the ratings and outlook for five public sector banks Bank of India (BOI), Syndicate Bank of India and Indian Overseas Bank (BOI).

S&P lowered its long-term issuer credit rating on India-based Bank of  India (BOI) to 'BB+' from 'BBB-'. The outlook is stable. At the same time, we lowered our short-term rating on the bank to 'B' from 'A-3'. We also lowered our issue ratings on BOI's senior unsecured debt to 'BB+' from 'BBB-' and our long-term issue ratings on the bank's Basel II compliant hybrid notes (upper Tier 2 subordinated and hybrid Tier 1 notes) to 'B' from 'B+'.

"We downgraded BOI because we expect the bank's asset quality to remain weak over the next 12 months, following a recent deterioration," said S&P Global Ratings credit analyst Amit Pandey.

S&P lowered its long-term issuer credit rating on India-based Syndicate Bank to 'BB+' from 'BBB-'. The outlook is stable. At the same time, we lowered our short-term rating on the bank to 'B' from 'A-3'. We also lowered our issue ratings on Syndicate's senior unsecured debt to 'BB+' from 'BBB-'.

''We downgraded Syndicate because we expect the bank's asset quality to remain weak over the next 12 months, following a deterioration in the past two quarters,'' said Amit Pandey.

S&P lowered its long-term issuer credit rating on India-based Indian Overseas Bank (IOB) to 'BB' from 'BB+'. The short-term rating remains 'B'. The outlook on the long-term rating is stable. At the same time, we lowered our issue ratings on IOB's senior unsecured debt to 'BB' from 'BB+'. At the same time, we removed the ratings from CreditWatch, where we had placed them with negative implications on Feb. 16, 2016.

''We downgraded IOB because we expect the bank's asset quality to remain weak over the next 12 months, following a deterioration in the past few quarters,''said Amit Pandey.