Tariffs may spike manufacturing costs for leading technology companies such as Apple and Nvidia that assemble and manufacture products outside the U.S.

US stocks whipsawed Tuesday after President Donald Trump made good on his threat to levy tariffs on Canada and Mexico, paving the way for a global trade war as leaders of both trading partners threatened retaliation.

U.S. stocks were down sharply Monday afternoon after U.S. President Donald Trump said 25% tariffs on Canada and Mexico will go into effect on Tuesday and reciprocal tariffs will start April 2, while the euro strengthened after European leaders agreed to draw up a Ukraine peace plan.

Enforcing the tariffs on Taiwan would be difficult, and they wouldn’t necessarily be enough to meaningfully increase semiconductor manufacturing in the United States, experts told WIRED.

CEO C.C. Wei credited President Donald Trump for the investments, which will include a new Arizona R&D center.