The U.S. government is sending a message to countries it believes are manipulating their currencies: We're watching you.

A Treasury report targets five countries in particular: China, Japan, Korea, Taiwan and Germany. Each meets at least two of the three criteria that "determine whether an economy may be pursuing foreign exchange policies that could give it an unfair competitive advantage against the United States."

At a time when currency devaluation has become a major tool used by multiple countries to stimulate growth, the U.S. is looking to protect its own interests. The report is an outgrowth of the Trade Facilitation and Trade Enforcement Act of 2015, a bipartisan effort aimed at stemming the global race to the bottom.

The criteria to determine whether a country should be on the "Monitoring List" of countries using unfair currency practices are: a trade surplus of larger than $20 billion, or 0.1 percent of U.S. GDP; a trade surplus with the U.S. that is more than 3 percent of that country's GDP; "persistent one-sided intervention," defined as purchases of foreign currency amounting to more than 2 percent of the country's GDP in a one-year period.

No country meets all three criteria, according to the report, though the five on the list meet at least two.