This drugmaker has rallied $15 billion in 11 days

Celltrion's market cap added $15 billion this year as it rallied to a record high on January 15

After a 57 per cent stock rally in 11 trading days this year, one analyst has decided that now is the time to give South Korea’s Celltrion Inc. a sell rating.

Nomura Securities Co analyst Cara Song initiated coverage on both Celltrion and Celltrion Healthcare Co in a report dated January 16, recommending investors sell the stocks as both have been trading at a “significant premium” to their five-year historical average price-to-earnings ratio compared to their peers.

Incheon-based Celltrion’s rally nudged past Hyundai Motor Co, South Korea’s largest automaker, to become the third-biggest company by value on the country’s stock