SEOUL/HANOI (Reuters) -Shares in South Korean and Vietnamese steelmakers, major Asian exporters of the metal to the United States, dropped on Monday after U.S. President Donald Trump said he would double tariffs on imported steel and aluminium to 50%.

President Trump said at a rally in Pennsylvania on Friday that he is going to double tariffs on steel imports from 25% to 50%. The hike, the president said, "will even further secure the steel industry in the United States.

President Trump said Friday that tariffs on imported steel and aluminum would increase to 50% from 25%, effective Wednesday.

The so-called TACO trade will be tested as markets wait to see if Trump will actually follow through with his latest threat or if he will put it on hold soon.

It was another week of policy pivots, back-and-forth trade headlines, and economic data that did little to anchor investor expectations. In the midst of the chaos, one phrase kept surfacing across Wall Street: the "TACO" trade.

Amid court challenges, the White House asserts confidence in President Donald Trump's tariff strategy, emphasizing the administration's focus on maintaining fair trade practices.

Wells Fargo's Christopher Harvey thinks a 10% tariff could be split evenly between importers, corporations, and consumers.

Homebuilder stocks rallied on Thursday, in a sign that residential construction will benefit from the ruling striking down Trump's tariffs.