Kotak has downgraded State Bank of India to 'accumulate' from 'buy' as the stock has risen too fast too quick belying the risk associated with its asset quality.

The stock has risen 15 percent last week, outperforming the broader market. Slippages remain at elevated levels run rate of 4 percent in the last two quarters and was "clearly negative in our view," Kotak Securities said in a note.

"Its 9 percent loan book is under stress (gross NPA at 4.6 percent and restructured book at 4.3 percent), which could be the potential risk," it added. At 11.46 a.m the stock was down 4.28 percent at 2,348.05 rupees.