Financial markets, which have shown increasing insensitivity to tariff threats from the US, will face a test at the Monday open after President Donald Trump declared a 30% rate for the European Union and Mexico effective Aug.

President Donald Trump has posted two new letters on his social media platform announcing tariffs on the European Union and Mexico.

President Donald Trump posted letters to the leaders of Mexico and the European Union, saying they had not done enough to head off the new tariffs.

It shows that personal grudges rather than simple economics are a driving force in the U.S. leader’s use of tariffs.

The president also decided to send out letters as a way to keep the pressure up.

Trump slapped a 50% tariff on Brazil, and Brazilian President Luiz Inacio Lula da Silva said his country would respond.

President Donald Trump posted several more letters on social media on Wednesday, setting tariff rates ranging from 20% for products from the Philippines to 30% for products from Algeria, Iraq, Sri Lanka,

European Commission President Ursula von der Leyen said that there needed to be a “genuine rebalancing” in the China-Europe relationship.