The Wall Street Journal reported Tuesday that Walgreens CEO Stefano Pessina reached out to AmerisourceBergen with the potential deal. Walgreens already owns about 26 percent of the company.
AmerisourceBergen jumped more than 13 percent, to $102.65 in premarket trading on Tuesday morning, Walgreen slipped 1.6 percent, to $67.40.
Walgreens Boots Alliance is the nation's largest drugstore operator. Control of AmerisourceBergen would provide the company with a tight grip on its supply chain. Walgreens is facing increased competition both from inside the sector and potentially imposing new rivals like Amazon (AMZN).