The RBI likely sold dollars via state-run lenders as the rupee slid to a more than two-month low below 55.50, four traders said on Friday.
"They seem to have been there in small amounts starting 55.50," the head of forex and debt trading at a private bank said, referring to the Reserve Bank of India.
Two other state-run bank dealers and one foreign bank dealer also confirmed spotting large selling by state-run banks starting at 55.50.
At 1:03 p.m. (0733 GMT), the partially convertible rupee was at 55.34/35 to the dollar, after hitting 55.53, its weakest since September 11.