From the Background: "The United States, a major source of, and destination for, foreign direct investment (FDI), is party to binding international investment agreements (IIAs) with over 50 countries. Taking the form of bilateral investment treaties (BITs) and investment chapters in free trade agreements (FTAs), these IIAs reduce FDI restrictions, ensure nondiscriminatory treatment of both investors and investment, and balance investment protections against other policy interests (such as safeguarding a host government's right to regulate in the public interest). While some World Trade Organization (WTO) agreements address investment issues in a limited manner, IIAs have been the primary tools for promoting investment and protecting investors. As of January 2021, more than 3,300 IIAs were concluded globally--forming a complex, overlapping network of investment rules."
CRS In Focus, IF10052
Congressional Research Service: https://crsreports.congress.gov/