The Wall Street Journal reported this Monday that Walgreens Boots Alliance Inc. (NASDAQ: WBA) has made a takeover approach to drug distributor AmerisourceBergen Corp. (NYSE: ABC). This move is expected to “boost profitability at the drugstore giant and insulate it against external threats in an increasingly competitive health-care landscape,” said Wall Street Journal.

Walgreens is the world’s largest drugstore chain with more than 13,000 in 11 countries. It is one of the world’s largest purchasers of prescription drugs, according to its website. Its brands include Walgreens, Duane Reade, Boots and beauty brands such as No7 and Soap & Glory. And Amerisource is one of the largest drug distributors in U.S.. In addition to supplying retail pharmacies, Amerisource also has a large specialty-drug business that distributes expensive medicines for cancer and other diseases directly to physicians and oncology clinics.

Even though representatives from both companies had no comments on this news, the report is not that shocking, since CVS Health is planning to acquire the health insurer Aetna at $69 billion. The idea behind this acquisition is the two companies can lower health costs by creating an integrated health system that combines pharmacy and health benefits with retail clinics, while Walgreens buying AmerisourceBergen could lower costs in a different way.

Except the threats from CVS Health, the fact that Amazon is entering health-care industry also gives anxiety to Walgreens. Amazon is now partnering with J.P. Morgan and Berkshire Hathaway to create a not-for-profit health-care company aimed at using technology to lower costs. That move, combined with chatter about other steps Amazon may take, have rocked health-related stocks.

According to Walgreens’s last quarterly securities filing, Walgreens owned about 56.9 million Amerisource shares, or about 26% of the company. As part of a pact with Amerisource, Walgreens can buy up to an additional 8.4 million shares in the open market, according to the filing.