CRISIL has assigned its 'AA-/Stable' rating to the Rs 25 billion additional Tier I bond issue (under Basel III) of IDBI Bank. It has reaffirmed its ratings on the bank's existing debt instruments at 'AA+/AA/FAAA/Stable/A1+'.

CRISIL believes that IDBI Bank will continue to receive strong support from GoI and will maintain its current scale of operations and market position, over the medium term.

''The outlook may be revised to 'Positive' if the bank significantly improves its resource and earnings profiles, without adversely affecting its asset quality. Conversely, the outlook may be revised to 'Negative' if there is a significant and sustained decline in IDBI Bank's asset quality and earnings profile,'' said CRISIL.

Shares of the bank declined Rs 3.9, or 5.46%, to settle at Rs 67.55. The total volume of shares traded was 858,373 at the BSE (Wednesday).