WASHINGTON: None of the United States’ major trading partners has been designated as manipulating its currency — including China — the Treasury Department said Friday, although Switzerland was added to a “monitoring list.”

China also warrants close observation, the Treasury added in a biannual report to Congress, over its failure to publish information on foreign exchange interventions and a “broader lack of transparency around key features of its exchange rate mechanism.”

The report looks at countries with big trade surpluses that actively intervene in foreign exchange markets to gain trade advantages.

“Most foreign exchange intervention by US trading partners last year was in the form of selling dollars, actions that served to strengthen their currencies,” said Treasury Secretary Janet Yellen in a statement.