owned unit in the United States, Ohm Laboratories Inc, to supply medicine to the world's largest economy, said the source, who declined to be named due to the sensitivity of the issue.
Ranbaxy, in which Japan's Daiichi Sankyo Co owns a 63.5 per cent stake, said it had not received any communication from the FDA on the import ban on the Mohali factory.
"We are seeking information from the USFDA in this regard," the company said in a statement issued to the stock exchanges.
Daiichi Sankyo and the FDA office in New Delhi could not be reached for comment.
A spokesman at the FDA's Washington headquarters said the agency has been in touch with the company.
India is the biggest overseas source of drugs for the United States and is home to more than 150 FDA-approved plants, including facilities run by global players. Pharmaceutical exports from India to the United States rose nearly 32 per cent last year to $4.23 billion.
The ban on its Mohali factory comes after the company pleaded guilty in May to US felony charges related to drug safety and agreed to a record $500 million in fines. After falling more than 40 per cent in the months afterwards, the share price had started to inch back up.
But its shares plummeted again on Monday, sinking as much as 32.6 per cent. The stock ended down 30.3 per cent at Rs. 318.50 in the main Mumbai market that fell 0.2 per cent. It has lost more than half its value from its highest level in 2008.
"It is a big risk for them in the long term. Ranbaxy was moving up on hopes of launches from this facility but those expectations are dashed now," said Aneesh Srivastava, chief investment officer at IDBI Federal Life Insurance.
Brokerages including HSBC, Edelweiss and India's Anand Rathi Research downgraded Ranbaxy, saying regulatory issues would continue to hurt the company's turnaround plans.
HSBC said Ranbaxy had started shipping generic Lipitor, the widely used cholesterol-lowering medicine, from its Mohali plant in April last year but six months later it recalled some of the batches due to the potential presence of glass