The US Treasury Department has found no evidence of manipulation of the yuan’s rate by China. President Trump has accused China of that several times. The country would keep the value of the currency artificially low, in order to stimulate exports.
Although according to a report from the ministry no evidence has been found for manipulation, China still remains on a kind of unofficial suspect list. Minister of Finance Mnuchin remains “particularly concerned” about the Chinese lack of transparency about the currency policy.
The United States and China are engaged in a trade war. The countries raise high tariffs on each other’s products. Trump wants to achieve, among other things, that the hundreds of billions of dollars of trade deficit with China will drop sharply. The value of the yuan has declined since the outbreak of this trade war, making Chinese products cheaper and thus even more favorable for import.