Mitsubishi Chemical will offer 2,010 yen for each share it doesn't already own in Mitsubishi Tanabe, it said in a statement to the Tokyo Stock Exchange. That is a 50% premium to the drugmaker's closing price of 1,338 yen per share in Tokyo trading.

The chemical maker already held more than 56% of shares in Mitsubishi Tanabe, Japan's eighth largest drugmaker by revenue, according to Refinitiv data.

The Osaka-based pharma company was the product of a 2007 merger between Mitsubishi Pharma Corp and Tanabe Seiyaku. It focuses on autoimmune, diabetes, renal and central nervous system treatments.

(Reporting by Rocky Swift; Editing by Muralikumar Anantharaman)