From the Document: "On August 4, China's central bank allowed its currency, the yuan, to depreciate to an 11-year low, breaking the politically sensitive threshold of seven yuan to one U.S. dollar (Figure 1). A depreciation of the yuan against the U.S. dollar makes Chinese exports less expensive in global markets. Some analysts speculate the depreciation is designed to offset and retaliate against U.S. tariffs on Chinese imports, coming four days after President Trump announced his intent to impose an additional 10% tariff on $300 billion of Chinese imports on September 1. There are differing views on the causes of yuan's movements, however, as discussed below. On August 5, Treasury Secretary Mnuchin, under the auspices of President Trump, determined that China is manipulating its currency. Although some policymakers have called for this designation for years and Donald Trump made it a central issue in his presidential campaign, the Treasury Department had not labeled a country as a currency manipulator in 25 years."
CRS Insight, IN11154
Congressional Research Service: https://crsreports.congress.gov/