Bain Capital is nearing a deal to buy Mitsubishi Chemical Group Corp.’s pharmaceutical unit, people familiar with the matter said, adding to a dealmaking boom in Japan.

U.S. private equity firm Bain Capital has bought Mitsubishi Tanabe Pharma in a deal worth 510 billion yen ($3.4 billion), saying it was encouraged by prospects of regulatory change for Japan's drug industry.

Bain Capital, a global private investment firm, has signed a definitive agreement to acquire Mitsubishi Tanabe Pharma Corporation (MTPC) from Mitsubishi Chemical Group Corporation. The investment values the business at approximately $3.3 billion.

The Japanese chemical company has agreed to sell its pharmaceutical business to Bain Capital for more than $3 billion, in a bid to focus on its key businesses.

Japan's Mitsubishi Chemical said on Friday it will sell pharmaceutical unit Tanabe Mitsubishi Pharma to U.S. private equity firm Bain Capital in a deal worth 510 billion yen ($3.36 billion) as it seeks to streamline its portfolio.