The Justice Department (DOJ) is nearly a year into a major sweep of the pharmaceutical industry for Foreign Corrupt Practices Act (FCPA) violations. Although the investigation has been low-profile so far–no charges have yet been filed–the effort has the potential to change the way drug and medical device companies do business.

“This is a huge deal because of the number of clinical trials run abroad and the percentage of drugs that are approved in the U.S. that derive from those trials,” says Glen Donath, a partner at Katten Muchin Rosenman.

Merck disclosed in an August SEC filing that it was under investigation. Eli Lilly previously made a similar disclosure. Many other major companies, including AstraZeneca, Baxter, Bristol-Myers Squibb, GlaxoSmithKline and Pfizer, have at least received letters of inquiry from the Justice Department about their practices abroad. This is probably just the tip of the iceberg, FCPA experts warn.