Reuters Market Eye - IPCA Laboratories Ltd shares plunge 15.7 percent to their lowest since September 2013.
Credit Suisse downgrades to "underperform" from "neutral", citing negative USFDA observations.
FDA's observations are on IPCA's Indore facility, Credit Suisse said.
Says two of these observations are critical, and could delay the recovery of U.S. sales for IPCA.
(Reporting by Indulal PM)
