President Donald Trump in recent days slapped tariffs as high as 50% on dozens of countries, restoring the type of aggressive trade policy that sent stocks plummeting a few months ago. The new round of levies prompted little more than a shrug on Wall Street.

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.

"Other trading partners observing these threats will have the same mistrust of the negotiation process," experts argue.

While Mexico was spared from Trump's so-called "Liberation Day" tariff rollout on April 2, the 30% rate for the E.U. is 10 percentage points higher than what the president said he would apply to America's largest trading partner in April but lower than his mid-May threat of 50%.

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

S&P 500 futures lost 0.5%, while Nasdaq 100 futures dropped 0.6%. Futures for the Dow Jones Industrial Average fell 204 points, or 0.5%.

The EU – the United States' biggest trading partner – had been scheduled to impose "countermeasures" starting Monday at midnight in Brussels

President Donald Trump threatened new tariffs on more than 20 countries this week, but his justification for raising import taxes on Brazil stands out.