WASHINGTON (Reuters) -The U.S. Treasury Department on Friday said Vietnam, Switzerland and Taiwan tripped its thresholds for possible currency manipulation under a 2015 U.S. trade law, but refrained from formally branding them as manipulators. In the first semi-annual foreign exchange report issued by Treasury Secretary Janet Yellen, the Treasury said it will commence “enhanced engagement” with Taiwan and continue such talks with Vietnam and Switzerland after the Trump administration labeled the latter two as currency manipulators in December. Treasury said Taiwan, Vietnam and Switzerland exceeded its 2015 currency thresholds during 2020 - a more than $20 billion bilateral trade surplus with the United States, foreign currency intervention exceeding 2% of gross domestic product and a global current account surplus exceeding 2% of GDP. Despite this finding, Treasury said there is insufficient evidence under an earlier 1988 law to conclude that Vietnam, Switzerland, or Taiwan are manipulating their exchange rates to gain a trade advantage or prevent balance of payments adjustments. “For calendar year 2020, we have not made a finding regarding the manipulation designation,” a Treasury official told reporters, adding: “We don’t view this as a mixed message.” The move takes some pressure off of Switzerland and Vietnam by lifting the manipulator designation at least for the next six months. The Swiss National Bank denied that it manipulates the Swiss franc and said the report will not alter its monetary policy. “In view of the economic situation and the ongoing high value of the Swiss franc, the SNB remains ready to intervene in the foreign exchange market if necessary,” the Swiss central bank said in a statement. An official with Taiwan’s central bank said the U.S. decision against applying the manipulator label showed that there was continued good communication between Taipei and Washington on the issue and that U.S. authorities understood Taiwan’s “special situation.”Taiwan’s tech-focused exports to the United States, including laptop computers and semiconductors, soared in 2020 due to the work-from-home boom sparked by the coronavirus pandemic. No immediate reaction was available from Vietnam. COVID-19 EFFECTS A Treasury official said it was possible for countries to meet the tests under the “mechanical” 2015 law and not be manipulating their currency to boost exports. He said the report’s findings took into account the massive trade and capital flow distortions of the pandemic and the fiscal and monetary policy choices governments took to respond to it. Without the pandemic, the “results would have likely been quite a bit different,” including for the three economies that hit the engagement triggers, the official added. Treasury’s report also said the COVID-19 crisis was likely to continue to affect current account positions over the next year as recoveries accelerated in some economies and lagged in others, adding that these changes were cause for concern. “Treasury is working tirelessly to address efforts by foreign economies to artificially manipulate their currency values that put American workers at an unfair disadvantage,” Yellen said in a statement. Slideshow ( 3 images ) The enhanced engagement includes formal talks to urge Vietnam, Switzerland and Taiwan to develop plans with specific actions to address underlying causes of currency undervaluation and external imbalances, Treasury said in a statement. The talks also will help Treasury determine the reasons for the three trading partners to make substantial currency market interventions. For Taiwan, Treasury said it would initiate enhanced engagement in line with the Trade Facilitation and Trade Enforcement Act of 2015. It expects those talks to help determine if Taiwan manipulated its currency under the 1988 law.