IPCA Laboratories Ltd shares plunged 15.7 per cent to their lowest since September 2013.
Credit Suisse downgraded the stock to "underperform" from "neutral", citing negative USFDA observations. FDA's observations are on IPCA's Indore facility, Credit Suisse said.
It said two of these observations are critical, and could delay the recovery of US sales for IPCA.
IPCA shares were trading down 10.37 per cent at Rs 668.90 as of 10.25 am.
Copyright: Thomson Reuters 2014